Nanopore Detection of Single-Molecule Binding within a Metallosupramolecular Cage

Article abstract of DOI:10.1002/chem.201800760

Guest encapsulation is a fundamental property of coordination cages. However, there is a paucity of methods capable of quantifying the dynamics of guest binding processes. Here, we demonstrate nanopore detection of single-molecule binding within metallosupramolecular cages. Real-time monitoring of the ion current flowing through a transmembrane α-hemolysin nanopore resolved the binding of different guests to both cage enantiomers. This enabled the single-molecule kinetics of guest binding to be quantified, whereas the ordering and durations of events were consistent with a guest-exchange mechanism that does not involve ligand dissociation. In addition to providing a new approach for single-molecule interrogation of dynamic supramolecular processes, this work also establishes that cage complexes which are too large to enter the nanopore can be exploited for detecting small molecules, thus constituting a new class of molecular adapter.

Full text of DOI:10.1002/chem.201800760

A Journal of
Accepted Article
Title: Nanopore Detection of Single-molecule Binding within a
Metallosupramolecular Cage
Authors: Stefan Borsley, James Arthur Cooper, Paul J. Lusby, and
Scott Lee Cockroft
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To be cited as: Chem. Eur. J. 10.1002/chem.201800760
Link to VoR: http://dx.doi.org/10.1002/chem.201800760
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Nanopore Detection of Single-molecule Binding within a
Metallosupramolecular Cage
Stefan Borsley,[a] James A. Cooper,[a] Paul J. Lusby[a] and Scott L. Cockroft*[a]
Abstract:
Guest encapsulation is a fundamental property of coordination cages.
However, there is a paucity of methods capable of quantifying the
dynamics of guest binding processes. Here, we demonstrate
nanopore
detection
of
single-molecule
binding
within
metallosupramolecular cages. Real-time monitoring of the ion current
flowing through a transmembrane -hemolysin nanopore resolved the
binding of different guests to both cage enantiomers. This enabled the
single-molecule kinetics of guest binding to be quantified, while the
ordering and durations of events were consistent with a guest-
exchange mechanism that does not involve ligand dissociation. In
addition to providing a new approach for single-molecule interrogation
of dynamic supramolecular processes, we also established that cage
complexes which are too large to enter the nanopore can be exploited
for detecting small molecules, thus constituting a new class of
molecular adapter.
Figure 1. (A) Experimental setup in which tetrahedral coordination cages were
detected at the cis-opening of a single α-hemolysin nanopore inserted in a lipid
bilayer under an applied transmembrane potential. (B)  (green) and ∆∆∆∆
(blue) homochiral forms of the GaIII4L612− cage used in this study. Each coloured
edge indicates the position of a bridging ligand molecule. (C) Range of well-
established[11-12] cationic guests employed in this study.
Coordination chemistry provides access to a diverse range of
supramolecular structures with remarkable properties.[1] For
example, the ability of metallosupramolecular cages to bind guest
molecules within an internal cavity has been widely exploited in
cage.[11] Therefore, we sought to explore whether the approach
might be extended to resolve the dynamic encapsulation of guests
within the transiently associated cage complexes (Figure 1). Such
an approach would resemble the use of -cyclodextrins,[13] cyclic
peptides[14] and cucurbit[6]urils,[15] which have been used as
supramolecular adapters in combination with the -hemolysin
nanopore to detect molecules that would otherwise be too small
to attenuate the ion current flowing through the nanopore (Figure
S25–S28). Such molecular adapters are deeply occluded, or even
covalently bound within the lumen of the pore. In contrast, the
cages shown in Figure 1B interact only transiently with the cis-
opening of the pore and are too large to enter it (cage diameter =
2.5 nm, cis- nanopore entrance = 2.5 nm Figure S35).[10] Thus, it
was not clear whether the molecular adapter principle could also
be exploited in transiently associated complexes, particularly
given the subtle changes that might be expected to arise from the
association of a small guest molecule within a substantially larger
and relatively rigid supramolecular cage.
molecular recognition and sensing,[2] gas separation,[3]
5]
stabilization of reactive species,[4] and catalysis.[4d,
This
abundance of applications combined with the desire to
incorporate more sophisticated functionalities into supramolecular
assemblies necessitates the development of a fundamental,
quantitative understanding of guest binding processes.[6] To date,
such studies have largely employed ensemble techniques, such
as NMR spectroscopy, to quantify the thermodynamic aspects of
binding.[7] However, accessing kinetic parameters using
ensemble techniques is often very challenging, especially where
6b, 6g, 6i, 8]
equilibration times are rapid.[6a,
In contrast, single-
molecule techniques may provide a means of observing the real-
time dynamics, distribution and ordering of processes occurring
on the molecular level.[9]
Here, we examine the ability of the ion current flowing
through a single -hemolysin nanopore embedded in a lipid
membrane to resolve the binding of single molecules within
12−
Initially, we synthesized a racemic mixture of the GaIII4L6
tetrahedral coordination cage (Figure 1B),[11] in the presence of a
tetramethylammonium guest (Me4N+, Figure 1C, pink). H NMR
individual enantiomers of
a
metallosupramolecular cage
1
(Figure 1). We recently established[10] that the experimental setup
depicted in Figure 1A could be used to discriminate between the
homochiral enantiomers of a GaIII4L612− tetrahedral coordination
spectroscopy revealed that each cage was associated with one
external Me4N+ and one encapsulated Me4N+ (Figure S3), in
accordance with literature chemical shifts.[11] Nanopore
experiments were conducted using a setup in which a planar lipid
bilayer was painted across a 100 µm aperture separating two
wells of buffered solution (1 M KCl, 30 mM phosphate, pH 8.0)
(Figures S1, S2). A single -hemolysin nanopore was introduced
into the bilayer, as indicated by the characteristic ionic current
flowing through the pore at an applied transmembrane voltage of
+100 mV (Io, Figure 2, S5). The addition of the Me4N+⊂cage
complex to a final concentration of ~0.5 M on the cis-side of the
[a]
Dr S. Borsley, Dr J. A. Cooper, Dr P. J. Lusby and Dr S. L. Cockroft
EaStCHEM School of Chemistry
University of Edinburgh, Joseph Black Building
David Brewster Road, Edinburgh EH9 3FJ, UK
E-mail: scott.cockroft@ed.ac.uk
Supporting information for this article is given via a link at the end of
the document.
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bilayer (Figure 1A) gave rise to temporal blockages of the ion
current at two major levels (green and blue bars in Figure 2),
corresponding to the two homochiral cage enantiomers (
and ∆∆∆∆).[10-11] Intriguingly, sub-levels were observed within
these major bands that we reasoned may arise from exchange
between the free cage and guest-encapsulated states (white lines,
Figure 2).[16] Indeed, data collated from multiple experiments and
consisting of several thousand blockage events revealed four
discrete Gaussian event distributions that could be tentatively
attributed to the two free cage enantiomers, and the two
Me4N+⊂GaIII4L612− inclusion complexes (Figure 3A).
Changes in the event distributions as the concentration of
Me4N+ was increased were used to assign the free and guest-
bound cages (e.g. Figure 3A → 3B, and Figures S31–S32 for
other concentrations). In contrast to the changes in the population
of states induced by varying the concentration of Me4N+, there
was no change in the magnitude of the residual currents of each
state, indicating that the M-concentration of non-encapsulated
Me4N+ ions had a negligible influence on the ion current in the 1
M KCl buffer solution employed. We next added a second,
competing guest to the experiment (s-nic+, Figure 1C, yellow,
Figure S4), which is known to bind more strongly to the cages.[12]
Figure 2. Representative ion current trace (1 M KCl, 30 mM phosphate, pH 8.0,
+100 mV, 293 ± 2 K) in the presence of 0.5 µM GaIII4L612−⊂Me4N+ on the cis-
side of the bilayer. Extended ion traces are provided in Figures S6, S7. Io is the
free-pore current.
Two new current levels were observed, which we attributed to the
12−
s-nic+⊂GaIII4L6
complexes (Figure 3B → 3C, yellow). The
relatively high population of new events despite the lower
concentration of s-nic+ compared to Me4N+ is also consistent with
stronger binding of the chrial cationic guest. The addition of further
s-nic+ further increased the relative population of these new states,
strongly indicating that these are attributable to the
12−
s-nic+⊂GaIII4L6
complexes (Figure 3C → 3D). Finally, an
excess of Et4N+ (Figure 1C, purple) was added, which is known
to outcompete s-nic+ binding within the cages.[6b] Accordingly, two
new levels were observed corresponding to the near total
formation of the Et4N+⊂GaIII4L612− complexes at the expense of all
previously observed states (Figure 3D → 3E). Notably, the
addition of n-Bu4N+ (Figures S21–S23) to a ~0.5 M solution of
the cage⊂Me4N+ complex did not generate any additional current
levels (Figure 3A → S24). Since n-Bu4N+ has previously been
shown to be too large to enter the cage, but may still interact via
external electrostatic interactions,[17] such a finding is consistent
with the hypothesis that the discrete current levels observed arise
from the encapsulation of different guests within the cage
complexes.
Interestingly, some encapsulated states increased the ion
current relative to the free cage, while others diminished it. For
example, Me4N+ binding within the  cage increased the ion
current, whereas Me4N+ binding within the  cage decreased
the ion current (Figure 3A and 3B). Conversely, Et4N+ binding
resulted in a decrease in ion current relative to the empty cage for
both  and  cages (Figure 3E). This observation
underlines the non-intuitive nature of ion currents, which are
difficult to predict.[18] Nonetheless, one may speculate that such
differences might arise from subtle variations in the shapes,
charge distributions, and/or solvation shells of each of the
complexes, all of which are further modulated by the
diastereomeric nature of the interactions with the pore.
Figure 3. Histograms of the residual currents (1 M KCl, 30 mM phosphate,
pH 8.0, +100 mV, 293 ± 2 K) observed across multiple titration experiments with
components being successively added to the cis-side of the membrane.
(A) [GaIII4L612−] = 0.5 M,
[Me4N+] = 1.0 M,
(B) [GaIII4L612−] = 0.5
M,
One benefit of single-molecule approaches is that they can
enable direct observation of association/dissociation events, and
the distribution of kinetics relating to these individual events. Thus,
having qualitatively established that guest binding within the
[Me4N+] = 9.3 M, (C) [GaIII4L612−] = 0.5 M, [Me4N+] = 9.3 M, [s-nic+] = 1.6 M,
(D) [GaIII4L612−] = 0.5 M, [Me4N+] = 9.3 M, [s-nic+], 3.2 M, (E) [GaIII4L612−] =
0.5 M, [Me4N+] = 9.3 M, [s-nic+] 3.2 M, [Et4N+] 161 M. Extended data
provided in Figures S6–S20.
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Table 1. Residual ion currents, kinetic and thermodynamic data for
voltage-driven GaII4L6⊂Me4N+ complexation determined from nanopore
experiments ([] = [∆∆∆∆] = 0.1 µM, 1 M KCl, 30 mM phosphate, pH 8.0,
+100 mV, 293 ± 2 K). Ka is given by kon/koff for each cage complex.

∆∆∆∆
GaIII4L612−⊂Me4N+
GaIII4L612−⊂Me4N+
Residual current, Ib/Io (free cage)
Residual current, Ib/Io (⊂Me4N+)
Guest association, kon /M−1 s−1
Guest dissociation, koff /s−1
0.64 ± 0.003
0.67 ± 0.003
2.61 ± 0.38 × 107
32 ± 2
0.79 ± 0.004
0.75 ± 0.005
2.66 ± 0.39 × 107
34 ± 2
Non-equilibrium association
constant at +100 mV, Knon-eq /M−1
8.3 ± 1.3 × 105
7.8 ± 1.2 × 105
independent of guest concentration, whereas on was linearly
dependent on concentration (Figure 4C–F). These concentration
dependencies confirmed the bimolecular nature of guest
encapsulation, and the unimolecular nature of guest expulsion
with each cage enantiomer. Moreover, this indicated that the
caveats outlined in the previous paragraph did not undermine the
integrity of this approach for this host-guest combination. Thus,
Figure 4. (A) Scheme showing guest kinetic parameters kon and koff for guest
12−
binding within a GaIII4L6
cage that is transiently associated with an -
hemolysin nanopore. (B) Illustration of event types from which guest binding
durations (off) and inter-event durations (on) can be determined. (C–F)
Experimental data showing association/dissociation kinetics of Me4N+ binding to
 and ∆∆∆∆ cages whilst transiently associated with an -hemolysin
nanopore as the concentration of Me4N+ is varied. [] = [∆∆∆∆] = 0.10 µM,
1 M KCl, 30 mM phosphate, pH 8.0, +100 mV, 293 ± 2 K. The rate constant kon
was obtained from the slope of the linear fit of 1/on versus [Me4N+] for (C) 
and (D) ∆∆∆∆ cages. The rate constant koff was obtained from the intercept of
the graph 1/off versus [Me4N+] for (E)  and (F) ∆∆∆∆ cages.
the voltage-driven rate constants of association, kon
=
1/(on[Me4N+]), and dissociation, koff = 1/off, could be determined
from the data in Figure 4C–F (Table 1). These experimentally
determined kon and koff values were the same within error,
indicating that the diastereotopic relationship between the cage
and the nanopore does not affect the guest binding process. The
ratio of kon/koff provides the association constant for guest binding
within the cage (Knon-eq, Table 1).[19] Consistent with previous
nanopore-based investigations of host-guest complexation,[13]
these non-equilibrium association constants (measured under an
applied potential of +100 mV) were found to be four orders of
magnitude greater than the equivalent association constants
measured at equilibrium.[11]
cages could be differentiated, we sought to quantify the kinetics
of guest binding at the single-molecule level (Figure 4A).[9] Such
a kinetic analysis can only be performed when there are sufficient
measurements of complete guest-binding durations (off, Figure
4B, iii and v), and inter-event durations (on, Figure 4B, iv and v)
during the periods in which the cage is associated with the pore
(Figure S29). The challenge with the present system is that cages
are only transiently associated with the pore (half-life ~30 ms),[10]
which limits the window in which cage-guest binding can be
observed. Indeed, incomplete binding/unbinding events (Figure
4B, i and ii) must be disregarded in such an analysis. Since a
complete kinetic analysis requires sufficient measurements
across a range of guest concentrations, the aforementioned
factors may make data collection time-consuming. Furthermore,
longer guest-binding events may be under-represented (e.g.
truncated bound state in Figure 4B, ii), which may limit the
accuracy of the determined kinetic parameters.
Nonetheless, we proceeded to see whether it was possible
to measure guest-binding kinetics at the single-molecule level.
GaIII4L612−⊂Me4N+ was added to a single nanopore experiment
under an applied transmembrane voltage of +100 mV. Me4N+ was
titrated into the experiment and single channel recordings
obtained (Figure S30–S32). Event durations and interevent
durations (off and on respectively, Figure 4B) were obtained and
plotted as frequency-count histograms, which were fitted to
single- exponential decay functions (Figure S33–S34) for each
cage-enantiomer. For both cage enantiomers, off was found to be
Notably, the single-molecule data presented herein
supports the previously proposed non-dissociative mechanism in
which all vertices of the cage remain intact during both guest entry
and exit.[6b, 20] Specifically, the distributions of event and inter-
event durations (off and on, respectively) follow single
exponential decay functions (Figure S33–S34), and no
intermediate states could be resolved between the guest-bound
and free states on the low-millisecond timescale (Figures 2, S7,
S10).
In conclusion, we have demonstrated a nanopore-based
approach for detecting the binding of single molecules within
individual metallosupramolecular cages. More specifically, the
magnitude of the ion current blockages arising from the transient
12−
association of enantiomeric tetrahedral GaIII4L6 cages with an
-hemolysin protein nanopore allowed individual cage-guest
complexes to be distinguished. The ability of this method to
resolve subtle differences between cage enantiomers and cage-
guest complexes is striking, particularly given that they are too
large to enter the pore.[10] Thus, this approach extends the
molecular adapter principle beyond established nanopore-
detection strategies in which smaller adapters reside deep within
the pore.[13-15] In common with other nanopore-based detection
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11429; n) Z. J. Wang, K. N. Clary, R. G. Bergman, K. N. Raymond, F. D.
Toste, Nat. Chem. 2013, 5, 100-103.
methods, the non-equilibrium (voltage-driven) nature of the
approach facilitates the detection of small molecules at
sub-micromolar concentrations. Similarly, direct observation of
guest binding within an individual cage grants access not only to
thermodynamic data, but also hard-to-obtain single-molecule
distributions of kinetic data. We hope that this work will encourage
the use of nanopore-based approaches for gaining insights into
other dynamic supramolecular systems, even where the
structures are too large to enter the pore.
[6]
a) M. M. J. Smulders, S. Zarra, J. R. Nitschke, J. Am. Chem. Soc. 2013,
135, 7039-7046; b) A. V. Davis, D. Fiedler, G. Seeber, A. Zahl, R. van
Eldik, K. N. Raymond, J. Am. Chem. Soc. 2006, 128, 1324-1333; c) C.
G. P. Taylor, W. Cullen, O. M. Collier, M. D. Ward, Chem. Eur. J. 2017,
23, 206-213; d) S. Turega, W. Cullen, M. Whitehead, C. A. Hunter, M. D.
Ward, J. Am. Chem. Soc. 2014, 136, 8475-8483; e) S. Mecozzi, J. J.
Rebek, Chem. Eur. J. 1998, 4, 1016-1022; f) J. L. Bolliger, T. K. Ronson,
M. Ogawa, J. R. Nitschke, J. Am. Chem. Soc. 2014, 136, 14545-14553;
g) W. Jiang, D. Ajami, J. Rebek, J. Am. Chem. Soc. 2012, 134, 8070-
8073; h) D. P. August, G. S. Nichol, P. J. Lusby, Angew. Chem. Int. Ed.
2016, 55, 15022-15026; Angew. Chem. 2016, 128, 15246-15250; i) O.
Chepelin, J. Ujma, X. Wu, A. M. Z. Slawin, M. B. Pitak, S.J. Coles, J.
Michel, A. C. Jones, P. E. Barran, P. J. Lusby, J. Am. Chem. Soc. 2012,
134, 19334-19337.
Experimental Section
[7]
[8]
C. Bohne, Chem. Soc. Rev. 2014, 43, 4037-4050.
a) L. Avram, A. D. Wishard, B. C. Gibb, A. Bar-Shir, Angew. Chem. Int.
Ed., 2017, 56, 15314-15318; Angew. Chem., 2017, 129, 15516-15520.
L. Ma, S. L. Cockroft, ChemBioChem 2010, 11, 25-34.
Experimental Details are provided in the SI.
[9]
[10] J. A. Cooper, S. Borsley, P. J. Lusby, S. L. Cockroft, Chem. Sci. 2017, 8,
5005-5009.
[11] D. L. Caulder, R. E. Powers, T. N. Parac, K. N. Raymond, Angew. Chem.
Int. Ed. 1998, 37, 1840-1843; Angew. Chem. 1998, 110, 1940-1943.
[12] a) A. V. Davis, D. Fiedler, M. Ziegler, A. Terpin, K. N. Raymond, J. Am.
Chem. Soc. 2007, 129, 15354-15363; b) A. J. Terpin, M. Ziegler, D. W.
Johnson, K. N. Raymond, Angew. Chem. Int. Ed. 2001, 40, 157-160;
Angew. Chem. 2001, 113, 161-164.
[13] a) L.-Q. Gu, O. Braha, S. Conlan, S. Cheley, H. Bayley, Nature 1999,
398, 686-690; b) J. Clarke, H.-C. Wu, L. Jayasinghe, A. Patel, S. Reid,
H. Bayley, Nat. Nanotechnol. 2009, 4, 265-270; c) L.-Q. Gu, H. Bayley,
Biophys. J. 2000, 79, 1967-1975.
Acknowledgements
We thank ERC Starting Grant 336935, “Transmembrane
molecular machines” for funding.
Keywords: single-molecule studies • supramolecular chemistry
• cage compounds • sensors • molecular recognition
[14] J. Sanchez-Quesada, M. R. Ghadiri, H. Bayley, O. Braha, J. Am. Chem.
Soc. 2000, 122, 11757-11766.
[15] O. Braha, J. Webb, L.-Q. Gu, K. Kim, H. Bayley, ChemPhysChem 2005,
6, 889-892.
[16] Our previous work (see ref. 10), employed a Tris buffer, which binds
strongly to the cages due to its close structural similarity to known
cationic guests. Thus, current levels observed in the previous work likely
arose from the GaIII4L612−⊂Tris-H+ complex.
[1]
a) G. F. Swiegers, T. J. Malefetse, Chem. Rev. 2000, 100, 3483-3538;
b) B. J. Holliday, C. A. Mirkin, Angew. Chem. Int. Ed. 2001, 40, 2022-
2043; Angew. Chem. 2001, 113, 2076-2097; c) R. Chakrabarty, P. S.
Mukherjee, P. J. Stang, Chem. Rev. 2011, 111, 6810-6918; d) S. R.
Seidel, P. J. Stang, Acc. Chem. Res. 2002, 35, 972-983; e) T. R. Cook,
P. J. Stang, Chem. Rev. 2015, 115, 7001-7045.
[17] T. N. Parac, D. L. Caulder, K. N. Raymond, J. Am. Chem. Soc. 1998,
120, 8003-8004.
[2]
a) R. Custelcean, P. V. Bonnesen, N. C. Duncan, X. Zhang, L. A. Watson,
G. Van Berkel, W. B. Parson, B. P. Hay, J. Am. Chem. Soc. 2012, 134,
8525-8534; b) Y. R. Hristova, M. M. J. Smulders, J. K. Clegg, B. Breiner,
J. R. Nitschke, Chem. Sci. 2011, 2, 638-641; c) T. K. Ronson, A. B.
League, L. Gagliardi, C. J. Cramer, J. R. Nitschke, J. Am. Chem. Soc.
2014, 136, 15615-15624; d) S. Turega, M. Whitehead, B. R. Hall, A. J.
H. M. Meijer, C. A. Hunter, M. D. Ward, Inorg. Chem. 2013, 52, 1122-
1132; e) C. García-Simón, M. Garcia-Borràs, L. Gómez, I. Garcia-Bosch,
S. Osuna, M. Swart, J. M. Luis, C. Rovira, M. Almeida, I. Imaz, D.
Maspoch, M. Costas, X. Ribas, Chem. Eur. J. 2013, 19, 1445-1456; f) C.
García-Simón, M. Garcia-Borràs, L. Gómez, T. Parella, S. Osuna, J.
Juanhuix, I. Imaz, D. Maspoch, M. Costas, X. Ribas, Nat. Commun. 2014,
5, 5557; g) P. D. Frischmann, V. Kunz, F. Würthner, Angew. Chem. Int.
Ed. 2015, 54, 7285-7289; Angew. Chem. 2015, 127, 7393-7397; h) H.
Takezawa, S. Akiba, T. Murase, M. Fujita, J. Am. Chem. Soc. 2015, 137,
7043-7046.
[18] S. F. Buchsbaum, N. Mitchell, H. Martin, M. Wiggin, A. Marziali, P. V.
Coveney, Z. Siwy, S. Howorka, Nano Lett. 2013, 13, 3890-3896.
[19] Unfortunately, a similar analysis could not be performed for the s-nic+
guest, as the residual current levels were coincident with the empty cage
(cf. Figure 3A and 3D).
[20] A. V. Davis, K. N. Raymond, J. Am. Chem. Soc. 2005, 127, 7912-7919.
[3]
[4]
a) M. B. Duriska, S. M. Neville, J. Lu, S. S. Iremonger, J. F. Boas, C. J.
Kepert, S. R. Batten, Angew. Chem. Int. Ed. 2009, 48, 8919-8922;
Angew. Chem. 2009, 121, 9081-9084; b) I. A. Riddell, M. M. J. Smulders,
J. K. Clegg, J. R. Nitschke, Chem. Commun. 2011, 47, 457-459.
a) S. Horiuchi, T. Murase, M. Fujita, J. Am. Chem. Soc. 2011, 133,
12445-12447; b) K. Nakabayashi, M. Kawano, M. Fujita, Angew. Chem.
Int. Ed. 2005, 44, 5322-5325; Angew. Chem. 2005, 117, 5456-5459; c)
P. Mal, B. Breiner, K. Rissanen, J. R. Nitschke, Science 2009, 324, 1697-
1699; d) W. M. Hart-Cooper, K. N. Clary, F. D. Toste, R. G. Bergman, K.
N. Raymond, J. Am. Chem. Soc. 2012, 134, 17873-17876.
[5]
a) C. J. Brown, F. D. Toste, R. G. Bergman, K. N. Raymond, Chem. Rev.
2015, 115, 3012-3035; b) C. J. Hastings, M. D. Pluth, R. G. Bergman, K.
N. Raymond, J. Am. Chem. Soc. 2010, 132, 6938-6940; c) Y. Jiao, J.
Wang, P. Wu, L. Zhao, C. He, J. Zhang, C. Duan, Chem. Eur. J. 2014,
20, 2224-2231; d) T. Murase, S. Horiuchi, M. Fujita, J. Am. Chem. Soc.
2010, 132, 2866-2867; e) M. Otte, P. F. Kuijpers, O. Troeppner, I.
Ivanović-Burmazović, J. N. H. Reek, B. de Bruin, Chem. Eur. J. 2013, 19,
10170-10178; f) D. Samanta, S. Mukherjee, Y. P. Patil, P. S. Mukherjee,
Chem. Eur. J. 2012, 18, 12322-12329; g) C. García-Simón, R. Gramage-
Doria, S. Raoufmoghaddam, T. Parella, M. Costas, X. Ribas, J. N. H.
Reek, J. Am. Chem. Soc. 2015, 137, 2680-2687; h) D. Fiedler, H. van
Halbeek, R. G. Bergman, K. N. Raymond, J. Am. Chem. Soc. 2006, 128,
10240-10252; i) D. H. Leung, R. G. Bergman, K. N. Raymond, J. Am.
Chem. Soc. 2007, 129, 2746-2747; j) M. D. Pluth, R. G. Bergman, K. N.
Raymond, Science 2007, 316, 85-88; k) M. D. Pluth, R. G. Bergman, K.
N. Raymond, Angew. Chem. Int. Ed. 2007, 46, 8587-8589; Angew. Chem.
2007, 119, 8741-8743; l) C. J. Hastings, D. Fiedler, R. G. Bergman, K. N.
Raymond, J. Am. Chem. Soc. 2008, 130, 10977-10983; m) M. D. Pluth,
R. G. Bergman, K. N. Raymond, J. Am. Chem. Soc. 2008, 130, 11423-
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10.1002/chem.201800760
Chemistry - A European Journal
COMMUNICATION
COMMUNICATION
Stefan Borsley, James A. Cooper, Paul
J. Lusby and Scott L. Cockroft*
Page No. – Page No.
Nanopore detection of single-
molecule binding within a
metallosupramolecular cage
Be my guest: A protein nanopore can resolve both the chirality of individual metallosupramolecular cages, and the dynamics of
encapsulation of different guests at the single-molecule level.
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