Synthesis and conformational analysis of poly(phenylacetylene)s with serinol-tethered carbohydrate appendages

Article abstract of DOI:10.1016/j.carres.2019.06.002

We synthesized phenylacetylenes containing β-lactoside, β-cellobioside, or β-maltoside, and polymerized them to produce the corresponding poly (phenylacetylene)s. In these poly (phenylacetylene)s, the pendent carbohydrates were tethered to the mainchains

Full text of DOI:10.1016/j.carres.2019.06.002

Accepted Manuscript
Synthesis and conformational analysis of poly(phenylacetylene)s with serinol-tethered
carbohydrate appendages
Kana Masubuchi, Masakiyo Maehata, Chieko Suzuki, Ryoji Matsuoka, Maki
Sekiguchi, Naoto Chigira, Yoshitsugu Amano, Mayu Inokuchi, Qintong Li, Teruaki
Hasegawa
PII:
S0008-6215(19)30123-5
https://doi.org/10.1016/j.carres.2019.06.002
CAR 7723
DOI:
Reference:
To appear in: Carbohydrate Research
Received Date: 28 February 2019
Revised Date: 17 May 2019
Accepted Date: 3 June 2019
Please cite this article as: K. Masubuchi, M. Maehata, C. Suzuki, R. Matsuoka, M. Sekiguchi, N.
Chigira, Y. Amano, M. Inokuchi, Q. Li, T. Hasegawa, Synthesis and conformational analysis of
poly(phenylacetylene)s with serinol-tethered carbohydrate appendages, Carbohydrate Research (2019),
doi: https://doi.org/10.1016/j.carres.2019.06.002.
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ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT
Title:
Synthesis and conformational analysis of poly(phenylacetylene)s with serinol-tethered
carbohydrate appendages
Authors:
a
a
a
b
Kana Masubuchi , Masakiyo Maehata , Chieko Suzuki , Ryoji Matsuoka , Maki
a
b
b
a
a
Sekiguchi , Naoto Chigira , Yoshitsugu Amano , Mayu Inokuchi , Qintong Li and
a
c
Teruaki Hasegawa , , ∗
Affiliations:
a
Faculty of Life Sciences, Toyo University, 1-1-1 Izumino, Itakura-machi, Ora-gun,
Gumma 374-0193, Japan,
b
Graduate School of Life Sciences, Toyo University, 1-1-1 Izumino, Itakura-machi,
Ora-gun, Gumma 374-0193, Japan,
c
Bio-Nano Electronics Research Centre, Toyo University, 2100 Kujirai, Kawagoe,
Saitama 350-8585, Japan.
∗
Corresponding author
E-mail address: t-hasegawa@toyo.jp
Abstract:
We synthesized phenylacetylenes containing β-lactoside, β-cellobioside, or
β-maltoside,
and
polymerized
them
to
produce
the
corresponding
poly(phenylacetylene)s. In these poly(phenylacetylene)s, the pendent carbohydrates
were tethered to the mainchains by serinol spacers. Because similar glycosyl serinol
units are found in the natural glycosphingolipids in cell membranes, the densely packed
carbohydrate clusters along the poly(phenylacetylene) mainchains act as molecular
mimics of cell surface glycoclusters. We analyzed the conformation of the glycosylated
poly(phenylacetylene)s using circular dichroism spectroscopy, and found that the spatial
carbohydrate packing within the glycoclusters changed on the addition of salts.
Key words:

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carbohydrate–carbohydrate interaction
spatial carbohydrate packing
glycocluster
poly(phenylacetylene)
helical structure
helix–coil transition
1
. Introduction
The glycosphingolipids (GSLs) in cell membranes aggregate laterally to form
GSL-enriched microdomains that present densely packed carbohydrate clusters
glycoclusters) on their surfaces (Fig. 1-(a)). [1] These cell surface glycoclusters play an
(
essential role in cell–cell adhesion via multivalent carbohydrate–carbohydrate
interactions (CCIs), wherein clustered GSLs on the surface of one cell recognize those
X
X
on the surface of an adjacent cell in a specific manner. [2,3] For example, Le –Le
interactions [4] and G 3–Gg3 interactions [5,6] induce compaction of blastomeres and
M
X
migration of cancer cells, respectively (See Chart S1 for the structures of Le , G 3, and
M
Gg3). These two examples of CCIs show that a clearer understanding of the
mechanisms behind CCIs would provide essential clues about human embryogenesis,
and facilitate the design of new drugs for preventing unfavorable cell–cell adhesion.
However, little molecular-level information has been obtained thus far concerning CCIs.
In particular, no information is available concerning detailed structures of glycoclusters
(e.g., spatial packing of carbohydrate units). The structural diversity of GSLs, the
multicomponent and fluidic nature of cell membranes, and the dynamic fluctuation of
their GSL levels, all combined together, makes it quite difficult to investigate CCIs in a
detailed and quantitative manner.
To circumvent these difficulties and to access molecular-level information on CCIs,
well-designed molecular mimics are vital in this field of research. [7–22] Molecular
mimics of cell surface glycoclusters thus far developed include synthetic polymers,
[
[
7,8] dendrimers, [9] peptides, [10,11] foldamers, [12] cyclodextrins, [13] liposomes,
14,15] and silica nanoparticle, [16–18] all having densely packed carbohydrate
appendages. Previous studies using these molecular mimics have revealed the unique
ion selectivity of CCIs; certain metal cations are required to induce CCIs. For example,
X
X
2+
Le –Le interactions were demonstrated by the Ca -induced aggregation of gold

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X
X
3
nanoparticles (GNPs) carrying multiple Le trisaccharides (Le , see Chart S1). [19]
Similar GNP-based systems carrying multiple lactoside units (Lac, see Chart S1) were
2
+
also used for probing Ca -induced Lac–Lac interactions. [20] It should be noted that
Lac is the carbohydrate unit of lactosylceramide (LacCer), which is one of the most
abundant GSLs in the cell membranes, and it is a common structural motif of various
X
2+
GSLs (e.g., Le , G 3, and Gg3). The Ca -induced Lac–Lac interactions were also
M
2
+
demonstrated using a polyfluorene with multiple Lac appendages; Ca induced
+
+
2+
association of the Lac-appended polyfluorene more efficiently than K , Na , Mg , or
2
+
Ba . [19] Dendrimers containing multiple Lac units interacted with lipid monolayers of
G 3 at an air–water interface on aqueous CaCl , thereby demonstrating Lac–G 3
M
2
M
2
+
interactions mediated by Ca . [9]
As these previous works have exemplified, researchers in this field commonly
2
+
believe the followings: (1) the specific metal cations (e.g., Ca in most cases) function
as molecular glue joining two carbohydrate units together; and (2) the formation of
multiple carbohydrate–cation–carbohydrate complexes is the main driving force for
inducing CCIs. Conversely, little attention has been paid to effects of ions on the spatial
packing of the carbohydrate units (hereafter referred to as glycopacking) within the
glycoclusters. In fact, only few studies have been carried out to reveal glycopacking of
the artificial glycoclusters. For example, Sasaki et al. developed glycosylated
oligopeptides as the molecular mimics of the cell surface glycoclusters, and used them
for investigating the effects of cations on the glycopacking. [10] Note that, in this
previous work, no attention was paid to the effects of anions on the glycopacking.
Fig. 1 Illustration of cell surface glycoclusters (a) and PPA-sugars as CD-active
molecular mimics of cell surface glycoclusters (b).

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During our series of investigations into the mechanism underlying CCIs, we recently
2
+
developed tris-bipyridine ferrous complexes ([Febpy ] ) with multiple carbohydrate
3
appendages (metalloglycoclusters) [23,24]. The most advantageous feature of the
2
+
metalloglycoclusters was their [Febpy3] core with the reversible N-Fe bonds. Each
metalloglycocluster comprised two diastereomers with right- and left-handed helical
2
+
[
Febpy ] cores (∆- and Λ-isomers, respectively), which were interconverted in water
3
at ambient temperature. Because the glycopacking of the metalloglycoclusters strongly
2
+
affect the ∆:Λ ratio of the [Febpy ] cores, the metalloglycoclusters act as molecular
3
probes for detecting the glycopacking changes within the glycoclusters. We conducted
circular dichroism (CD) spectroscopy measurements on the metalloglycoclusters and
found that the ∆:Λ ratios were changed on additions of the salts, thereby demonstrating
the considerable impact of the salt on the glycopacking. It should be emphasized that in
2
+
+
2+
+
-
-
this previous work, not the cations (Ca , Na , Mg , or K ) but the anions (Cl , NO , or
3
2
-
SO ) had a critical effect on the glycopacking.
4
Although the previous research using the metalloglycoclusters demonstrated that the
glycopacking changes were mainly anion-dependent, the mechanism by which anions
affect the glycopacking remained unclear. There were some weak points in the design of
2
+
the metalloglycoclusters: (1) the divalent positive charges of the [Febpy ] cores; and
3
2
+
(2) the phenyl spacers that connected the carbohydrate appendages to the [Febpy3]
cores. The former aspect of design should present attractive and repulsive forces to the
anions and the cations, respectively. They should result in an overestimation and an
underestimation of the effects of anions and cations, respectively. The latter aspect of
design also exemplifies the structural difference between the metalloglycoclusters and
the natural GSLs on cell surfaces. Together, these weak points reduce the validity of the
metalloglycoclusters as molecular mimics of cell surface glycoclusters and the
reliability of our new finding that the anions play substantial roles to change the
glycopackings.
Chart 1. Structures of (left) the natural GSLs and (right) the PPA-sugars.

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To overcome these weak points, we recently developed new artificial glycoclusters
with poly(phenylacetylene) (PPA) mainchains (PPA-sugars) as molecular mimics, and
used them to investigate the glycopacking changes mediated by salts (Fig. 1-(b)). It is
known that PPAs adopt right- (P) and left-handed (M) helical structures that
interconvert in a polar solvent at ambient temperature [25]. Because PPAs have no
charge, it is possible to elucidate the effect of various ions more precisely using
PPA-sugars. Moreover, the PPA-sugars have serinol spacers that are similar to those of
the natural GSLs in the cell membranes (Chart 1). Herein, we report the protocols for
preparing the PPA-sugars, and their salt-induced conformational changes.
2
2
. Results and Discussion
.1. Synthesis of PPA-sugars
We treated commercially available 4-ethynylbenzoic acid (1) with SOCl to produce
2
4
-ethynylbenzoyl chloride (2), then coupled it with methyl-
-serine unit via an amide linkage (3)
Scheme 1). Subsequent glycosylation with per-acetylated lactose (AcLac) yielded
L-serine to produce
phenylacetylene conjugated with a methyl-
L
(
phenylacetylene containing per-acetylated Lac (PA-LacAc, Scheme 2). We also
synthesized similar compounds containing per-acetylated cellobioside (PA-CelAc) and
per-acetylated maltoside (PA-MalAc) via similar synthetic procedures using
per-acetylated cellobiose (AcCel) and per-acetylated maltose (AcMal), respectively.
The glycosylated phenylacetylenes were then treated with NaBH to convert the methyl
4
esters into the hydroxymethyl groups. Subsequent deacetylation with NaOMe produced
phenylacetylene monomers containing Lac, Cel, and Mal units with serinol spacers
(PA-Lac, PA-Cel, and PA-Mal, respectively). The chemical compositions of these
1
monomers were confirmed by their proton nuclear magnetic resonance ( H NMR),
1
3
carbon-13 NMR ( C NMR), infrared (IR), and high-resolution electrospray ionization
time-of-flight mass (HR ESI-TOF MS) spectra.

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Scheme 1. Reaction conditions: i) SOCl , room temperature (rt), 1 day, ii)
2
methyl-L-serine, Et N, tetrahydrofuran (THF), water, 1 h, 75% (2 steps).
3
Scheme 2. Reaction conditions: i) per-acetated sugars, BF OEt , CH Cl , under N , rt,
3
2
2
2
2
2
.5–7.0 h, 61–90%, ii) NaBH , THF, water, 0 ºC, 10–15 h, iii) NaOMe, MeOH, rt,
4
overnight, 61–78% (2 steps), iv) [Rh(nbd)Cl] , Et N, DMF, under N , rt, 3–5 h, 57–
2
3
2
9
0%.
We then polymerized the monomers in N,N-dimethylformamide (DMF) containing
Rh(nbd)Cl] as a catalyst to produce the corresponding polymers containing multiple
[
2
copies of Lac, Cel, and Mal appendages along their mainchains (PPA-Lac, PPA-Cel,
and PPA-Mal, respectively). The resulting PPA-sugars were readily soluble in water.
According to size exclusion chromatography (SEC) analysis using SB-804 HQ (Shodex,
Japan; Pullulan Standard), the number-average molecular weights (Mn) of PPA-Lac,
4
4
4
PPA-Cel, and PPA-Mal were 6.8 × 10 , 1.7 × 10 , and 2.3 × 10 , respectively (Fig. S1).
Pale yellow aqueous solutions of PPA-Lac, PPA-Cel, and PPA-Mal had almost identical
UV-vis spectra with predominant peaks at 274 nm accompanied by broad shoulders
around 400 nm (Fig. 2 and Fig. S2). The broad shoulders were attributable to the
conjugated mainchains of the PPA-sugars, proving their successful preparation. It is

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widely recognized that PPAs of different conjugated lengths sometimes have different
UV-vis spectra. Therefore, the almost identical UV-vis spectra of these PPA-sugars
indicated that their helical contents (i.e., [P helix] + [M helix]) were almost the same. It
should also be noted that the aqueous PPA-sugars caused no light scattering, as
supported by the almost zero absorption in the long wavelength region (ca. 700–800
nm). These data clearly demonstrate the high solubility of the PPA-sugars in water.
1
Although the PPA-sugars were highly soluble in water, the H NMR spectra of the
PPA-sugars in D O were highly broadened, possibly because of the densely packed
2
glycosyl serinol appendages along the mainchains (see Supporting Information). The
1
highly broadened H NMR spectra of the PPA-sugars strongly hindered their structural
and conformational analysis through the NMR spectroscopy measurements. For
example, it is widely believed that the PPA derivatives obtained by the polymerization
using [Rh(nbd)Cl] as a catalyst have cis-transoidal structures along the mainchains and
2
1
they show characteristic H signals at 5–7 ppm. [26] However, in the cases of the
1
PPA-sugars in this work, only broad signals were observed at this region of their H
NMR spectra.
Fig. 2. UV-vis spectra of the PPA-sugars. [PPA-sugars] = 5.56 mM, d = 0.2 mm, rt, in
water.
2
.2. CD spectra of the PPA-sugars in pure water
Although the PPA-sugars had almost identical UV-vis spectra, their CD spectra
differed depending on their carbohydrate units. For example, PPA-Lac had a CD
spectrum with a positive–negative–positive CD pattern composed of three peaks
centered at 378, 308, and 272 nm, respectively (Fig. 3). This CD pattern was quite

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similar to those of the helical PPAs carrying chiral pendent groups reported by Yashima
et al., suggesting that PPA-Lac also adopted a cis-transoidal structure with a helical
conformation. [25] Although this CD spectrum offered no decisive information on the
sense of the helix (i.e., P or M helix) in PPA-Lac, our molecular dynamics (MD)
calculation indicated that the P helix was a stable conformer of PPA-Lac (see the
following section for details). Therefore, we will discuss the conformation of
PPA-sugars based on an assumption that the positive–negative–positive CD pattern is
indicative of the P helical structure.
Although PPA-Cel had a similar positive–negative–positive CD pattern, its peak
intensities were lower than those of PPA-Lac. The lower CD intensities of PPA-Cel
indicated a smaller diastereomer excess (i.e., [P helix] - [M helix]) than that of PPA-Lac.
Note that the structures of PPA-Lac and PPA-Cel differed only in the C4 configurations
in their non-reducing terminal carbohydrates (i.e., the axial hydroxy group of the former
and the equatorial one of the latter). It was quite surprising that such small structural
difference located remotely from the PPA mainchains clearly affected their CD spectra.
It is also quite interesting to compare the CD spectra of PPA-Cel and PPA-Mal. As
shown in Fig. 3, PPA-Mal had a negative–positive–negative CD pattern, although the
negative band in the wavelength region below 300 nm had no clear peak. This CD
spectrum indicated that PPA-Mal had the opposite helix sense to that of PPA-Cel. Given
our assumption that PPA-Lac and PPA-Cel adopt the P helical structure, the CD
spectrum of PPA-Mal indicates a M helical structure. The opposite helix senses of
PPA-Cel and PPA-Mal were quite interesting if we considered the fact that these
polymers differed only in the anomeric configuration of their non-reducing terminal
glucosides (βGlc for PPA-Cel and αGlc for PPA-Mal). Note again that the non-reducing
terminal glucosides located remotely from the polymer mainchain and the PPA-sugars
have other chiral sources (e.g., the L-serinol spacers and the reducing βGlc terminals) as
their common structural motif located in close proximity to the mainchain. Given the
design concept of PPA-sugars, these findings suggest that the carbohydrate units in
GSLs are the main structural factors that induce specific glycopacking within the
glycoclusters on cell surfaces.

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Fig. 3. CD spectra of the PPA-sugars. [PPA-sugars] = 5.56 mM, d = 1.0 mm, rt, in
water.
2
.3. MD simulation
As described in the previous section, the CD spectral analysis of the PPA-sugars
revealed their helical structures. It was also indicated that the helix sense of PPA-Mal
was opposite to those of PPA-Lac and PPA-Cel. However, it was impossible to tell from
the CD spectra whether the PPA-sugars adopted P or M helices. In an attempt to clarify
the senses of the helices in the PPA-sugars, we conducted MD simulations on PPA-Lac,
a representative of the PPA-sugars, as follows. Briefly, before starting the MD
simulation, we created a P helical 12-mer of polyacetylene (i.e., H-(CH -CH=CH) -H)
2
12
with no pendent group, and conducted a molecular mechanics (MM) calculation (force
field: CHARMM) on this P helical 12-mer. The stable P helix obtained from the MM
calculation had no disordered (e.g., random coil-like) structure along its helical
mainchain (Fig, 4-(a)). We then reversed the spatial coordinates of each atom of this P
helical 12-mer with respect to the z-axis (i.e., from (x, y, z) = (a, b, c) to (-a, -b, c)) and
constructed another 12-mer that adopted the stable M helical structure. Note that these P
and M helical 12-mers were mirror images of each other, and therefore had identical
potential energies. We then attached lactosyl serinol units tethered with phenyl spacers
to every third carbon atom of the polymer chains (i.e., H-(CH -CR=CH) -H, R =
2
12
pendent lactosyl serinols with phenyl spacers), thereby constructing 12-mers of
PPA-Lac with P and M helices (Fig. 4-(b)). Note that these 12-mers were diastereomers
of each other owing to different combinations of the opposite chirality of their
mainchains (i.e., P and M helices) and the identical chirality of their pendent groups (i.e.,
lactosyl serinol units). Because of this diastereomeric nature, these two 12-mers had

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different glycopackings and different potential energies.
We then conducted MD simulations (300 K, implicit solvent model,
ε = 80, 6000 ps
equilibration, 5000 ps dynamics, CHARMM) on these two 12-mers, and found that the
average potential energies during the dynamics step were 96.9 and 100.2 kcal/molresidue
for the P and M helices, respectively (Fig. 4-(c)). The lower potential energy of the P
helix than that of the M helix suggests that PPA-Lac preferentially adopts the P helical
structure in water. Note that the 12-mers of P and M helical PPA-Lac retained their
original helix senses throughout the MD simulations, and we observed no helix
inversion. The exceptions were the terminal regions; the conformations in these regions
gradually changed into random coil-like structures during the MD simulations (Fig.
4
-(d)).
Fig. 4 (a) Stable P helix of polyacetylene (12-mer) having no pendent group produced
by the MM calculation, (b) P helix of PPA-Lac (12-mer) before the MD simulation, (c)
time-course of potential energies of P and M helical PPA-Lac during the MD simulation,
and (d) the most stable P helix of PPA-Lac (12-mer) during the MD simulation (See Fig.
S3 for the colored version of these pictures).

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2
.4. Time-dependent CD spectral changes of PPA-sugars
As described in Section 2.2, we conducted the CD spectroscopy measurements on
the sample solutions prepared using the fresh stock solutions of the PPA-sugars.
However, during our research, we found that the CD spectrum of each PPA-sugar varied
depending on how long its stock solution had been stored. For example, if we prepared
the PPA-Lac samples using the stock solutions that had been stored for different periods,
the CD signals weakened as the period of storage increased (Fig. 5-(a)). It should be
noted that in contrast to the evident CD spectral changes during the storage, PPA-Lac
exhibited only negligible UV-vis spectral changes with different storage periods.
Furthermore, we detected no light scattering due to aggregation, even in a PPA-Lac
sample prepared using a stock solution that had been stored for 25 days. The almost
identical UV-vis spectra implied that the total helical content of PPA-Lac did not change
during the storage, and the weakened CD signals arose from lower diastereomer excess.
We observed similar CD spectral changes for PPA-Cel and PPA-Mal; the former and the
latter still had positive–negative–positive and negative–positive–negative CD patterns,
respectively, but the signals became weaker with the increasing storage periods. These
CD spectral changes during the storage lasted for at least 3–4 weeks, indicating that
PPA-sugars underwent prolonged conformational changes in water (Fig. 5-(b)).
Fig. 5 (a) Time-dependent CD spectral changes of PPA-Lac, and (b) plots of CD
intensities of the PPA-Lac (open circles), PPA-Cel (open squares), and PPA-Mal (open
triangles) at 378 nm against periods of storage of the stock solutions used for the sample
preparations. The samples were incubated for overnight after their preparations and then,
subjected to the CD spectroscopy measurements. [PPA-sugars] = 5.56 mM, d = 1.0 mm,
rt, in water.

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2
.5. Salt-induced CD spectral changes of PPA-sugars
As mentioned above, the conformations of the PPA-sugars gradually changed in
water. These conformational changes reduced the reproducibility of the CD spectra, and
therefore greatly hindered quantitative evaluation of the salt-induced conformational
changes of the PPA-sugars. To avoid this problem, we simultaneously prepared sample
solutions of the PPA-sugars with and without salts using the stock solutions that had
been stored for identical periods, and conducted CD spectroscopy measurements of
those solutions. By following this protocol, we were able to ignore the effect of storage
on the stock solutions, and assess the effects of the salts on the conformations of the
PPA-sugars, as detailed below.
Interestingly, PPA-Lac exhibited a different CD spectral response to the different
salts. For example, CaCl and MgCl weakened and enhanced the CD signals of
2
2
PPA-Lac, respectively (Fig. 6-(a)). In contrast to CaCl and MgCl , NaCl had a
2
2
negligible effect on the CD signals of PPA-Lac. Because all these salts (CaCl , MgCl ,
2
2
-
and NaCl) had Cl as the common anion, these CD spectral responses indicate
cation-induced conformational changes of PPA-Lac. It should be, however, emphasized
that not only the cations but also the anions affected the conformation of PPA-Lac. This
is clearly indicated by the different CD spectra of PPA-Lac obtained using CaCl and
2
2
+
Ca(NO ) . Because these salts had Ca as the common cation, the different CD spectral
3
2
-
-
responses clearly indicate that Cl and/or NO also played a substantial role in the CD
3
spectral changes exhibited by PPA-Lac.

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Fig. 6 (a) Relative CD spectra of PPA-Lac in the presence and the absence of the salts
whose intensities were normalized based on the CD374 signal of the PPA-Lac aqueous
solution ([salts] = 0 M) (See Fig. S4 for the colored version of this graph), and relative
CD intensities (374 nm) of (b) PPA-Lac, (c) PPA-Cel, and (d) PPA-Mal in the presence
of various salts compared to the CD intensities of the corresponding PPA-sugars without
salts. [PPA-sugars] = 5.56 mM, d = 1.0 mm, rt, in water.
The salt-induced conformational changes of PPA-Lac were assessed in more detail
by the similar CD spectroscopy measurements with varying salt concentrations (Fig.
6
-(b)). We thereby found that the conformational change of PPA-Lac had unique
concentration dependency towards the salts. For example, CaCl did not change the CD
2
signal intensities of PPA-Lac when CaCl concentration ([CaCl ]) was lower than 1.00
2
2
M. However, CaCl clearly lowered the CD signals of PPA-Lac with increasing [CaCl ]
2
2
when [CaCl ] was higher than 1.00 M. The nitrate salts (e.g., NaNO and Ca(NO ) )
2
3
3 2
also weakened the CD intensities, but the concentration dependencies of the nitrates

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differed from that of CaCl ; the CD signals were lowered by the nitrate salts with
2
increasing their concentrations even when the concentration of the nitrate salts were
lower than 1.00 M. The conformational change of PPA-Lac also had unique
concentration dependency towards MgCl ; the CD signals of PPA-Lac were enhanced
2
with increasing [MgCl ] when [MgCl ] were lower than 1.00 M while they were
2
2
weakened with increasing [MgCl ] when [MgCl ] were higher than 1.00 M. We also
2
2
assessed the effect of Na SO on the CD spectrum of PPA-Lac and found that the CD
2
4
spectrum changed only slightly in the presence of Na SO . Note that we could not
2
4
assess the effect of Na SO with its concentrations higher than 0.75 M due to its limited
2
4
water solubility.
Interestingly, different PPA-sugars showed different CD spectral responses towards
the salts. For example, MgCl slightly lowered the CD signals of PPA-Cel and PPA-Mal.
2
The lowered CD signals were clear contrast to the enhanced CD signal of PPA-Lac in
the presence of MgCl . These data clearly indicated that C4 configurations of their
2
non-reducing terminal carbohydrates (axial, equatorial, and equatorial for PPA-Lac,
2
+
PPA-Cel and PPA-Mal, respectively) played important roles for the Mg -induced
conformational changes. Another informative difference among the CD spectral
responses of the PPA-sugars was their different CD spectral changes with the nitrate
salts; the nitrate salts lowered the CD signals of PPA-Lac and PPA-Cel more
significantly than that of PPA-Mal. These data may indicate that the anomeric
configurations of the non-reducing terminal carbohydrates (i.e., β-, β-, and
α-configurations for PPA-Lac, PPA-Cel, and PPA-Mal, respectively) play an important
-
role for the NO -induced conformational changes.
3
3
. Conclusions
We synthesized the PPAs containing β-lactosides, β-cellobiosides, and β-maltosides,
and conducted their circular dichroic spectroscopy measurements in the presence and
the absence of the salts. Each of the glycosylated PPAs showed characteristic circular
2
+
2+
-
dichroic spectral responses towards the specific ions (Mg , Ca , and NO ). The
3
glycosylated PPAs have the serinol spacers connecting the pendent carbohydrates to the
mainchains and their densely packed carbohydrates reasonably mimicked the cell
surface glycoclusters composed of GSLs. In addition, their PPA mainchains acted as
circular dichroic probes for monitoring the spatial carbohydrate packings along their

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strands. Therefore, the salt-induced conformational changes herein reported implied the
important roles of the specific cations and anions for the spatial carbohydrate packings
within the cell surface glycoclusters. However, the minimum salt-concentrations (~200
mM) required for the glycopacking changes of the PPA-sugars were much higher than
+
2+
their physiological concentrations (e.g., normal serum Na and Ca concentrations are
ca. 140 mM and ca. 2.3 mM, respectively). Further investigation is thus required to
reach the final conclusion of the relationship between the salts and the glycopacking of
the cell surface glycoclusters.
4
. Experimental
4
.1. General
1
13
H and C NMR spectra were acquired on a JEOL AL300 spectrometer (JEOL
Resonance, Ltd., Japan) in CDCl or D O. Chemical shifts were reported in ppm (δ)
3
2
relative to TMS or internal references such as HOD. Matrix-assisted laser desorption
ionization time-of-flight (MALDI-TOF) mass spectra were recorded on a SHIMAZU
AXIMA–CFR+ (SHIMAZU, Ltd., Japan) or SHIMAZU AXIMA–Confidence
(SHIMAZU, Ltd., Japan). IR spectra were recorded on a JASCO FT/IR–4100 Fourier
transform infrared spectrometer (JASCO Co., Ltd., Japan). UV–vis spectra were
recorded on a V–630 UV-visible spectrophotometer (JASCO Co., Ltd., Japan) equipped
with a one-drop accessory (SAH–769). Circular dichroism (CD) spectra were acquired
on a JASCO J-820 spectropolarimeter (JASCO Co., Ltd., Japan) using a micro sampling
disk (MSD–462). Silica gel 60 N (spherical, neutral, particle size 63–210 µm) for
column chromatography was purchased from Kanto Chemical Co., Inc., Japan. Thin
®
layer chromatography (TLC) was carried out with Whatman TLC glass plates (Partisil
K6F) pre-coated with silica gel (60 Å) with a fluorescent indicator (λ = 254 nm).
Dialysis Membranes for dialysis were purchased from Fisher Scientific Co., Ltd. (USA).
Cellobiose, 4-ethynylbenzoic acid, tetrahydrofurane, BF OEt , and sodium methoxide
3
2
were purchased from FUJIFILM Wako Pure Chemical Co. (Japan). Anhydrous MgSO4
was purchased from SHOWA Chemical Co., Ltd. (Japan). Sodium hydrogen carbonate
was purchased from AGC Chemicals Co., Ltd. (Japan). L-Serine was purchased from
the Tokyo Chemical Industry Co. Ltd. (Japan). Thionyl chloride, chloroform, lactose
monohydrate, maltose, triethylamine, and sodium methoxide were purchased from the
Kanto Chemical Co. (Japan). Dichloromethane, methanol, and toluene were purchased

ACCEPTED MANUSCRIPT
from GODO Co., Ltd. (Japan). All these chemicals and materials were used without
purification.
4
.2. Methyl-L-serine (SerMe)
To -serine (4.02 g) in MeOH (50 ml), thionyl chloride (2.7 ml) was added and the
L
resultant mixture was refluxed with magnetic stirring for overnight. The mixture was
then evaporated to dryness and the residue was re-dissolved into MeOH (25 ml).
Toluene (25 ml) was then added to the mixture and the mixture was slowly stirred by
shaking the vessel with hands at every tens minutes until precipitate formed. The
precipitate was retrieved through filtration and dried in vacuo to give the titled
1
compound (SerMe) as white powder in 32% yield. The product showed H NMR
spectrum that was identical to that in the literature [27].
4
.3. 4-Ethynylbenzoyl chloride (2)
To 4-ethynylbonzoic acid (207 mg), thionyl chloride (10 ml) was added and the
resultant heterogeneous mixture was magnetically stirred at ambient temperature for 1
day. The reaction mixture was then evaporated to dryness. 4-Ethynylbenzoyl chloride
was thereby obtained as the brownish orange solid and it was used immediately to the
following reaction.
4
.4. N-p-Ethynylbenzoyl-serine methyl ester (PA-Ser, 3)
To a THF solution (50 ml) containing methyl- -serine (220 mg), water (5 ml) and
L
Et N (1 ml) were added to obtain a homogeneous mixture. To this homogeneous
3
solution, a THF solution (10 ml) containing 4-ethynylbenzoyl chloride (2) prepared in
the previous section in THF (10 ml) was added and the magnetic stirring was continued
for 1 h at ambient temperature. The mixture was then evaporated to dryness and the
residue was subjected to purification on silica gel (CHCl : MeOH = 100: 0 to 95:5 v/v,
3
gradient) and the title compound (PA-Ser, 3) was thereby obtained as white powders in
its pure form in 75% yield (2 steps from 4-ethynylbonzoic acid); IR (KBr): 1755, 1554,
–
1 1
1
522, 1370, 1346, 1234, and 1038 cm ; H NMR (300 MHz, CDCl ) δ 7.78 (d, J = 8.1
3
Hz, 2H), 7.55 (d, J = 8.1 Hz, 2H), 7.16 (d, J = 8.4 Hz, 1H), 4.86 (quin, J = 3.3 Hz, 1H),
1
3
4
.11–4.01 (m, 2H), 3.82 (s, 3H), 3.23 (s, 1H), 2.79 (br s, 1H); C NMR (75 MHz,
CDCl ) δ 171.0, 166.8, 133.4, 132.3, 127.2, 125.9, 82.6, 79.9, 63.4, 55.1, 53.0;
3

ACCEPTED MANUSCRIPT
+
MALDI-TOF MS, [M+H] = 248.02 (calc. 248.09).
4
.5.
General
synthetic
protocol
to
prepare
N-p-ethynylbenzoyl-O-(per-O-acetyl-glycosyl)-serine methyl ester (PA-sugarsAc)
To each of the per-acetylated carbohydrates (AcLac, AcCel, or AcMal), PA-Ser (3),
CH Cl , and BF OEt were added, and the resultant mixture was magnetically stirred
2
2
3
2
under N at ambient temperature. After complete consumption of PA-Ser was confirmed
2
by TLC analysis (CHCl /MeOH = 12/1 v/v), the reaction mixture was diluted with ethyl
3
acetate. The organic layer was then washed with NaHCO saturated aqueous solutions,
3
repeatedly. The resultant organic layer was dried over anhydrous MgSO , filtrated, and
4
evaporated to dryness. The residue was then subjected to silica-gel column purification
(
CHCl /MeOH = 100/0 to 96/4 v/v, gradient) to retrieve the title compound in its pure
3
form. It should be noted that because of the neighboring group participations from the
equatorial –OAc groups at the C2 of the glycosyl donor (AcLac, AcCel, and AcMal),
the corresponding β-anomers (PA-LacAc, PA-CelAc, and PA-MalAc, respectively) were
exclusively formed through the glycosylation.
4
.5.1.
PA-LacAc)
AcLac: 2.60 g; PA-Ser: 473 mg; CH Cl : 10 ml; BF OEt : 3 ml; reaction time: 7 h;
N-p-Ethynylbenzoyl-O-(per-O-acetyl-lactosyl)-serine
methyl
ester
(
2
2
3
2
–1 1
yield: 70%; IR (KBr): 1755, 1554, 1522, 1370, 1346, 1234, and 1038 cm ; H NMR
300 MHz, CDCl ) δ 7.81 (d, J = 8.4 Hz, 2H), 7.59 (d, J = 8.4 Hz, 2H), 6.98 (d, J = 7.8
(
3
Hz, 1H), 5.34 (d, J = 2.4 Hz, 1H), 5.16 (t, J = 3.3 Hz, 1H), 5.09 (dd, J = 7.5 and 10.2 Hz,
1
4
3
2
1
7
2
4
H), 4.97–4.85 (m, 3H), 4.51–4.45 (m, 3H), 4.30 (dd, J = 3.0 and 10.5 Hz, 1H), 4.16–
.02 (m, 2H), 3.98 (dd, J = 3.3 and 10.5 Hz, 1H), 3.86 (t, J = 7.2 Hz, 1H), 3.79 (s, 3H),
.60–3.55 (m, 1H), 3.23 (s, 1H), 2.36 (s, 3H), 2.15 (s, 3H), 2.11 (s, 3H), 2.06 (s, 3H),
1
3
.04 (s, 3H), 1.98 (s, 3H), 1.96 (s, 3H); C NMR (75 MHz, CDCl ) δ 170.4, 170.3,
3
70.2, 170.1, 169.7, 169.6, 169.1, 166.1, 133.4, 132.4, 127.1, 126.0, 101.1, 100.7, 82.6,
9.9, 76.0, 72.8, 72.5, 71.5, 70.9, 70.7, 69.0, 66.6, 61.7, 60.8, 53.0, 52.9, 20.8, 20.8,
+
0.7, 20.6, 20.5; MALDI-TOF MS: [M+H] = 888.17 (calc. 888.26).
.5.2.
PA-CelAc)
AcCel: 1.75 g; PA-Ser: 303 mg; CH Cl : 10 ml; BF OEt : 3 ml; reaction time: 2.5 h;
N-p-Ethynylbenzoyl-O-(per-O-acetyl-cellobiosyl)-serine
methyl
ester
(
2
2
3
2
–1 1
yield: 90%; IR (KBr): 1755, 1554, 1522, 1370, 1346, 1234, and 1038 cm ; H NMR

ACCEPTED MANUSCRIPT
(
300 MHz, CDCl ) δ 7.71 (d, J = 8.4 Hz, 2H), 7.59 (d, J = 8.4 Hz, 2H), 6.95 (d, J = 7.8
3
Hz, 1H), 5.14 (dd, J = 1.2 and 9.9 Hz, 1H), 5.12 (d, J = 9.3 Hz, 1H), 5.06 (t, J = 9.3 Hz,
1
H), 4.92 (dd, J = 2.4 and 7.5 Hz, 1H), 4.90 (d, J = 4.8 Hz, 1H), 4.88 (dd, J = 8.1 and
.9 Hz, 1H), 4.53–4.47 (m, 3H), 4.36 (dd, J = 4.2 and 12.3 Hz, 1H), 4.30 (dd, J = 3.0
9
and 10.5 Hz, 1H), 4.08 (dd, J = 4.8 and 12.3 Hz, 1H), 4.03 (d, J = 11.4 Hz, 1H), 3.99
dd, J = 3.6 and 10.5 Hz, 1H), 3.79 (s, 3H), 3.75 (t, J = 9.0 Hz, 1H), 3.67–3.62 (m, 1H),
.62–3.53 (m, 1H), 3.22 (s, 1H), 2.12 (s, 3H), 2.09 (s, 3H), 2.02 (s, 3H), 2.01 (s, 6H),
(
3
1
1
7
2
4
1
3
.98 (s, 3H), 1.93 (s, 3H); C NMR (75 MHz, CDCl ) δ 170.5, 170.3, 170.1, 169.7,
3
69.5, 169.3, 169.0, 166.1, 133.4, 132.4, 127.0, 126.0, 100.8, 82.6, 79.9, 76.2, 72.9,
2.8, 72.1, 72.0, 71.5, 71.4, 69.0, 67.7, 61.6, 61.5, 53.0, 52.9, 20.8, 20.7, 20.6, 20.6,
+
0.5; MALDI-TOF MS: [M+Na] = 888.05 (calc. 888.26).
.5.3.
PA-MalAc)
AcMal: 1.76 g; PA-Ser: 303 mg; CH Cl : 10 ml; BF OEt : 3 ml; reaction time: 3.5 h;
N-p-Ethynylbenzoyl-O-(per-O-acetyl-maltosyl)-serine
methyl
ester
(
2
2
3
2
–1 1
yield: 61%; IR (KBr): 1755, 1554, 1522, 1370, 1346, 1234, and 1038 cm ; H NMR
300 MHz, CDCl ) δ 7.82 (d, J = 8.4 Hz, 2H), 7.59 (d, J = 8.4 Hz, 2H), 6.97 (d, J = 7.8
(
3
Hz, 1H), 5.40 (d, J = 4.2 Hz, 1H), 5.34 (t, J = 9.9 Hz, 1H), 5.22 (t, J = 9.0 Hz, 1H), 5.05
t, J = 9.6 Hz, 1H), 4.96–4.91 (m, 1H), 4.84 (dd, J = 3.9 and 7.5 Hz, 1H), 4.80 (dd, J =
.8 and 9.3 Hz, 1H), 4.57 (d, J = 8.1 Hz, 1H), 4.47 (dd, J = 2.7 and 12.3 Hz, 1H), 4.33
dd, J = 2.7 and 10.5 Hz, 1H), 4.23 (td, J = 3.6 and 12.3 Hz, 2H), 4.07–3.92 (m, 4H),
.80 (s, 3H), 3.67–3.64 (m, 1H), 3.22 (s, 1H), 2.13 (s, 3H), 2.10 (s, 3H), 2.04 (s, 3H),
(
7
(
3
2
1
9
5
8
1
3
.03 (s, 3H), 2.00 (s, 3H), 2.00 (s, 3H), 1.93 (s, 3H); C NMR (75 MHz, CDCl ) δ
3
70.5, 170.4, 170.1, 170.1, 169.9, 169.6, 169.4, 166.1, 133.4, 132.4, 127.1, 125.9, 100.5,
5.5, 82.6, 79.8, 76.6, 75.0, 72.4, 72.3, 72.0, 70.0, 69.3, 69.2, 68.5, 67.9, 62.5, 61.4,
+
3.0, 52.9, 20.9, 20.8, 20.7, 20.6, 20.6, 20.6; MALDI-TOF MS: [M+Na] = 888.15 (calc.
88.26).
4
2
.6.
-(R)-N-p-ethynylbenzoylamino-3-O-glycosyl-1-propanol (PA-sugars)
To each of the PA-sugarAc in THF, NaBH in water was added and the resultant
General
synthetic
protocol
to
prepare
4
mixture was stirred at 0 ºC. After complete conversion of the methyl ester to the
hydroxymethyl group was confirmed by TLC analysis (CHCl /MeOH = 12/1 v/v), the
3
resultant mixture was evaporated to dryness. The residue was then re-dissolved in

ACCEPTED MANUSCRIPT
MeOH (20 ml) and a catalytic amount of NaOMe was added to the resultant mixture.
The mixture was stirred at ambient temperature for overnight. During this deacetylation
step, a suitable amount of water was added at appropriate times to keep the reaction
mixture homogeneous. The homogeneous mixture was evaporated to dryness. The
residue was then subjected to purification on HP-20 (Mitsubishi Chemical, Co., Japan)
using aqueous MeOH with increasing MeOH concentration ([MeOH] = 0–100%,
gradient) as an eluent. The fractions that contained pure PA-sugar were combined,
evaporated, and lyophilized to afford the title compound in its pure form.
4
.6.1. 2-(R)-N-p-ethynylbenzoylamino-3-O-lactosyl-1-propanol (PA-Lac)
PA-LacAc: 182 mg; THF: 7 ml; NaBH : 59 mg; H O: 3 ml; reaction time for the
4
2
reduction reaction: 10 h; yield: 61%; IR (KBr): 3388, 2888, 1638, 1544, 1499, 1322,
–1 1
and 1074 cm ; H NMR (300 MHz, D O) δ 7.61 (d, J = 8.1 Hz, 2H), 7.49 (d, J = 8.1
2
Hz, 2H), 4.34 (t, J = 8.4 Hz, 2H), 4.23 (quin 8.33 (d, J = 9.3 Hz, 2H), 7.15 (d, J = 9.0
Hz, 2H), 5.49 (t, J = 9.9 Hz, 1H), 5.36 (t, J = 9.0 Hz, 1H), 5.31–5.20 (m, 2H), 5.09–5.00
(m, 3H), 4.88 (dd, J = 3.6, 10.2 Hz, 1H), 4.08 (dd, J = 4.5, 12.6 Hz, 1H), 4.04–3.79 (m,
4
2
1
6
4
H), 3.53 (dd, J = 1.8, 9.6 Hz, 2H), 2.12 (s, 3H), 2.10 (s, 3H), 2.08 (s, 3H), 2.07 (s, 3H),
1
3
.06 (s, 3H), 2.06 (s, 3H), 1.81 (s, 3H); C NMR (75 MHz, D O) δ 171.6, 134.5, 132.8,
2
27.9, 125.7, 103.5, 103.0, 78.9, 75.9, 75.3, 74.8, 73.3, 73.0, 71.5, 69.4, 69.1, 61.6, 61.1,
+
0.6, 52.3; HR ESI-TOF MS: [M+Na] = 566.1740 (calc. 566.1850 for C H NNaO ).
2
4
33
13
.6.2. 2-(R)-N-p-ethynylbenzoylamino-3-O-cellobiosyl-1-propanol (PA-Cel)
PA-CelAc: 254 mg; THF: 10 ml; NaBH : 91 mg; H O: 3 ml; reaction time for the
4
2
reduction reaction: 15 h; yield: 78%; IR (KBr): 1755, 1554, 1522, 1370, 1346, 1234,
–1 1
and 1038 cm ; H NMR (300 MHz, D O) δ 7.61 (d, J = 8.1 Hz, 2H), 7.49 (d, J = 8.1
2
Hz, 2H), 4.34 (t, J = 8.4 Hz, 2H), 4.23 (quin, J = 5.4 Hz, 1H), 3.93 (dd, J = 6.3 and 10.8
Hz, 1H), 3.82-3.54 (m, 7H), 3.48–3.45 (m, 3H), 3.38–3.25 (m, 3H), 3.20–3.12 (m, 2H);
1
3
C NMR (75 MHz, CDCl ) δ 171.6, 135.0, 133.3, 128.4, 126.2, 103.6, 103.5, 79.6,
3
7
7.0, 76.5, 75.8, 75.2, 74.2, 73.9, 70.5, 69.9, 61.6, 61.0, 52.8; HR ESI-TOF MS:
+
[
M+Na] = 566.1738 (calc. 566.1850 for C H NNaO ).
2
4
33
13
4
.6.3. 2-(R)-N-p-ethynylbenzoylamino-3-O-maltosyl-1-propanol (PA-Mal)
PA-MalAc: 252 mg; THF: 10 ml; NaBH : 100 mg; H O: 3 ml; reaction time for the
4
2
reduction reaction: 10 h; yield: 77%; IR (KBr): 1755, 1554, 1522, 1370, 1346, 1234,
–1 1
and 1038 cm ; H NMR (300 MHz, D O) δ 7.59 (d, J = 8.4 Hz, 2H), 7.48 (d, J = 7.8
2
Hz, 2H), 5.22 (d, J = 3.6 Hz, 1H), 4.32 (d, J = 7.8 Hz, 1H), 4.21 (t, J = 4.8 Hz, 1H),

ACCEPTED MANUSCRIPT
3
.91 (dd, J = 6.3 and 11.1 Hz, 1H), 3.75-3.37 (m, 14H), 3.24 (t, J = 9.3 Hz, 1H), 3.15 (t,
1
3
J = 8.7 Hz, 1H); C NMR (75 MHz, D O) δ
171.5, 134.9, 133.2, 128.3, 126.1, 103.4,
2
1
00.5, 77.6, 77.0, 75.5, 73.9, 73.7, 73.6, 72.6, 70.2, 69.8, 61.6, 61.5, 61.4, 52.7; HR
+
ESI-TOF MS: [M+Na] = 566.1749 (calc. 566.1850 for C H NNaO ).
2
4
33
13
4
.7.
poly(4-(1'-(2"-O-glycosyl)-2'-hydroxyethylaminocarbonyl)phenylacetylenes
PPA-sugars)
To each of the PA-sugars (PA-Lac, PA-Cel, or PA-Mal) in degassed DMF, a degassed
DMF solution containing [Rh(nbd)Cl] and Et N was added and the resultant mixture
General
synthetic
protocol
to
prepare
(
2
3
was stirred at ambient temperature under N . The resultant dark brown solution was
2
poured into excess amount of methanol to precipitate the corresponding PPA-sugars
(PPA-Lac, PPA-Cel, or PPA-Mal, respectively). The precipitate was retrieved by
filtration and then, re-dissolved in water, and the resultant aqueous solution was
subjected to dialysis (MWCO3500) in water. The resultant aqueous solution was
subjected to lyophilization to afford the title compound as pale-yellow cotton-like solid.
4
.7.1. Poly(4-(1'-(2"-O-lactosyl)-2'-hydroxyethylaminocarbonyl)phenylacetylenes
PPA-Lac)
PA-Lac: 101 mg; DMF: 2.0 ml; [Rh(nbd)Cl] : 4.1 mg; DMF: 1.3 ml; Et N: 5 drops;
(
2
3
reaction time: 3.5 h; yield: 90%; IR (KBr): 3356, 2893, 1638, 1543, 1322, 1070, and
–
1
1
13
1
034 cm ; H NMR (300 MHz, D O): δ 7.38 (br), 4.21 (br), 3.41 (br); C NMR (75
2
MHz, D O): δ 169.8, 127.8, 103.5, 78.8, 75.9, 75.3, 74.7, 73.4, 73.1, 71.5, 69.1, 61.6,
2
6
1.2, 60.6, 51.9.
4
.7.2.
Poly(4-(1'-(2"-O-cellobiosyl)-2'-hydroxyethylaminocarbonyl)phenylacetylenes
PPA-Cel)
PA-Cel: 101 mg; DMF: 2.0 ml; [Rh(nbd)Cl] : 4.1 mg; DMF: 1.3 ml; Et N: 5 drops;
(
2
3
reaction time: 5.0 h; yield: 57%; IR (KBr): 3352, 2889, 1636, 1544, 1322, 1147, 1071,
–
1 1
and 1038 cm ; H NMR (300 MHz, D O): δ 7.70 (br), 4.00 (br), 3.91 (br), 3.55 (br);
2
1
3
C NMR (75 MHz, D O): δ 128.3, 103.6, 80.0, 77.0, 76.6, 75.8, 75.3, 74.2, 73.9, 70.6,
2
6
1.8.
4
.7.3. Poly(4-(1'-(2"-O-maltosyl)-2'-hydroxyethylaminocarbonyl)phenylacetylenes
(PPA-Mal)

ACCEPTED MANUSCRIPT
PA-Mal: 101 mg; DMF: 2.0 ml; [Rh(nbd)Cl] : 4.1 mg; DMF: 1.3 ml; Et N: 5 drops;
2
3
reaction time: 3.0 h; yield: 65%; IR (KBr): 3355, 2891, 1636, 1542, 1321, 1074, and
–
1 1
1
036 cm ; H NMR (300 MHz, D O): δ 7.41 (br), 5.17 (br), 4.21 (br), 3.46 (br), 3.10
2
1
3
(
br); C NMR (75 MHz, D O): δ 169.7, 133.2, 128.7, 103.7, 100.9, 78.8, 77.0, 75.7,
2
7
4.0, 73.7, 72.8, 70.4, 69.5, 61.6, 52.4.
Acknowledgement:
This research did not receive any specific grant from funding agencies in the public,
commercial, or not-for-profit sectors.
Declaration of interest
Declarations of interest: none
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Supplementary Materials
X
Supplementary data related to this article containing structures of Le , G 3, Gg3,
M
and LacCer (Chart S1), size exclusion chromatograms of PPA-sugars (Fig. S1), a
photograph of aqueous solutions of PA-Lac and PPA-Lac (Fig. S2), colored versions of
1
13
Fig. 4 and Fig. 6 (Fig. S3 and Fig. S4, respectively), and H/ C NMR spectra of the
newly synthesized compounds in this paper are available online free of charge.

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Highlights:
Poly(phenylacetylene)s containing multiple carbohydrates with serinol spacers
Helical structures revealed by circular dichroic spectroscopy analysis
Salt-induced conformational change of the glycosylated poly(phenylacetylene)s