Auyuittuqamides A-D, Cyclic Decapeptides from Sesquicillium microsporum RKAG 186 Isolated from Frobisher Bay Sediment

Article abstract of DOI:10.1021/acs.jnatprod.0c00966

Four new cyclic decapeptides, auyuittuqamides A-D (1-4), were obtained from Sesquicillium microsporum RKAG 186 obtained from marine sediment collected from the intertidal zone of Frobisher Bay, Nunavut, Canada. The structures of the compounds were elucida

Full text of DOI:10.1021/acs.jnatprod.0c00966

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Article
Auyuittuqamides A−D, Cyclic Decapeptides from Sesquicillium
microsporum RKAG 186 Isolated from Frobisher Bay Sediment
Alyssa L. Grunwald, Christopher Cartmell, and Russell G. Kerr*
Cite This: J. Nat. Prod. 2021, 84, 56−60
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sı Supporting Information
ABSTRACT: Four new cyclic decapeptides, auyuittuqamides A−D
1−4), were obtained from Sesquicillium microsporum RKAG 186
(
obtained from marine sediment collected from the intertidal zone of
Frobisher Bay, Nunavut, Canada. The structures of the compounds
were elucidated by NMR spectroscopy and tandem mass spectrom-
etry. The absolute configurations of the amino acids were determined
using Marfey’s method.
yclic peptides constitute a large portion of non-
ribosomally synthesized peptides. Due to their increased
RESULTS AND DISCUSSION
■
C
S. microsporum RKAG186 was isolated from a sediment sample
collected in Frobisher Bay, Nunavut, on yeast malt medium
supplemented with cottonseed oil. The isolate was identified
based on analysis of the ITS nucleotide sequence and
morphological observations. Isolate RKAG 186 had 98.4%
ITS nucleotide sequence identity to S. microsporum NRRL
4217 (GenBank accession no. GU219471.1) and was
identified as such.
A 1.5 L solid agar fermentation of S. microsporum RKAG 186
was performed. The fermentation was extracted with EtOAc,
structural integrity over linear peptides, cyclic peptides have
1
attracted much attention in recent years. With the ability to
cyclize in numerous positions along the peptide backbone,
cyclic peptides present immense structural diversity, leading to
2
a plethora of biological activities being observed.
Fungi are well known for the production of natural products
and have been isolated from a wide range of habitats, although
there are very few reports of fungi isolated from polar marine
5
3
environments. Fungi from polar intertidal environments face
many unique challenges and must be able to withstand extreme
cold, high ultraviolet radiation, freeze−thaw cycles, and low
water and nutrient availability. Despite these environmental
challenges, polar marine fungi have proven to be an
dried, and partitioned between 80% CH CN and hexane. The
3
CH CN-soluble portion was subjected to flash chromatog-
3
raphy and RP HPLC, yielding four new cyclic decapeptides,
auyuittuqamides A (1) (4 mg), B (2) (1.5 mg), C (3) (3 mg),
and D (4) (2 mg). The compounds were named after the
Inuktitut word “auyuittuq”, meaning “the land that never
melts”.
Auyuittuqamide A (1) (Figure 1, Table 1) was obtained as a
white powder, and HRESIMS supported a molecular formula
4
−6
increasingly fruitful sources of new natural products.
Due to its inaccessibility, Canada’s arctic has remained a
largely untapped resource for microbial natural product
discovery. Within the Kerr lab, ongoing bioprospecting efforts
from Frobisher Bay, Nunavut, have led to the isolation of
several new natural products including the tetramic acid-
of C H N O , requiring 15 degrees of unsaturation. The
50 82 10 12
7
peptidic nature of the compound was determined by analysis
containing natural products iqalisetins A and B from the
1
of the H NMR spectrum, which revealed the presence of
fungal isolate Tolypocladium sp. RKAG 373, the cyclic
8
seven amide protons and three N-methyl amide substituents
heptapetide mortiamides A−D from the fungal isolate
1
3
(
δH 2.78, 3.16, 3.24), while the C NMR spectrum revealed
Mortierella sp. RKAG 110, and the amphiphilic siderophore
9
imaqobactin from the bacterial isolate Variovorax sp. RKJM
2
85. As part of this continued arctic bioprospecting effort, a
Received: September 2, 2020
Published: December 24, 2020
strain of Sesquicillium microsporum (RKAG 186) was isolated
from sediment collected from Frobisher Bay and found to
produce four new cyclic decapeptides (1−4). The isolation,
structure elucidation, and biological activities of these
compounds are reported within.
©
2020 American Chemical Society and
American Society of Pharmacognosy
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5
6
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the presence of 10 amide carbonyls (δ 167.6−173.3) and 10
C
α-amino acid carbon resonances (δ 43.0−70.2). Analysis of
C
COSY, HMBC, HSQC, and TOCSY spectra confirmed the
identity of the amino acid constituents and revealed the
presence of two Val, two Gly, one Ser, one Ile, one Leu, one N-
Me-Phe, one N-Me-Val, and one N-Me-Thr residue within the
molecule. In order to account for the remaining degree of
unsaturation, it was determined that this compound must be
cyclic. There were three options for the mechanism of
cyclization: it could either cyclize between the N- and C-
terminal amino acids in a peptide bond or cyclize at the C-
terminal amino acid and the hydroxy of the threonine or serine
Figure 1. Two-dimensional structural characterization of 1 showing
(A) key COSY (bold lines), HMBC (blue solid arrows), and ROESY
(red dashed arrows) correlations. (B) Structure of 1 with absolute
configuration assigned.
10
side chain in an ester linkage. Due to the presence of free
hydroxy groups for the Ser (δ 4.86) and Thr (δ 4.67) side
H
H
chains, it was determined that this molecule cyclized in a
peptide bond between the N-terminal and C-terminal amino
acids.
The order of the amino acids was determined using HMBC
and ROESY correlations and tandem mass spectrometry.
N-Me-Phe-Gly-Ile-Ser-Val-N-Me-Val-Gly-Leu-]. MS/MS anal-
ysis confirmed the sequence of the peptide (Figure S5).
Auyuittuqamide B (2) (Table S1) was obtained as a white
HMBC correlations from Val-1 NH-7 (δ 8.70) to N-Me-Thr
powder, and HRESIMS supported a molecular formula of
C H N O , requiring 15 degrees of unsaturation. The H
49 80 10 12
H
1
C-1 (δ 169.0), N-Me-Thr H -5 (δ 3.15) to Leu C-45 (δ
C
3
H
C
1
73.4), Leu NH-46 (δ 7.46) to Gly-2 C-43 (δ 168.3), and
NMR spectrum was very similar to that of 1 and indicated 2
was an analogue of 1 that differed by the absence of a
methylene group. Analysis of the COSY and TOCSY spectra
indicated the Ile residue was replaced by a Val residue. HMBC
H
C
Gly-2 NH-44 (δH 7.45) to N-Me-Val C-37 (δC 169.5)
established the five amino acid sequence N-Me-Val-Gly-Leu-
N-Me-Thr-Val. HMBC correlations from Ile NH-24 (δ 7.44)
H
to Gly-1 C-21 (δ 167.7) and Gly-1 NH-22 (δ 7.76) to N-
correlations from Val-3 NH-24 (δ 7.41) to Gly-1 C-21 (δC
C
H
H
Me-Phe C-11 (δC 169.9) established the three amino acid
fragment lle-Gly-N-Me-Phe. A third fragment (Ser-Val) was
established by HMBC correlations from Val-2 NH-33 (δH
167.8) and ROESY correlations from Ser NH-29 (δ 8.59) to
H
Val-3 H-24 (δH 4.38) confirmed the new Val residue had
replaced the Ile residue in the same location. The identity and
sequence of the other amino acids were confirmed by NMR
analysis and tandem mass spectrometry to be identical to 1.
Therefore 2 was assigned as cyclo [-N-Me-Thr-Val-N-Me-Phe-
Gly-Val-Ser-Val-N-Me-Val-Gly-Leu-].
8
.91) to Ser C-29 (δ 170.2). Due to the overlapping carbonyl
C
chemical shifts of Val-1, Val-2, and Ile (δ 171.6−171.7), these
C
three fragments could not be definitively connected through
HMBC correlations. ROESY correlations from N-Me-Val H3-
4
2 (δ 3.25) to Val-2 H-33 (δ 4.53), Ser NH-30 (δ 8.57) to
Auyuittuqamide C (3) (Table S2) was obtained as a white
H
H
H
Ile H-24 (δ 4.42), and N-Me-Phe H -20 (δ 2.77) to Val-1
H-7 (δ 4.48) connected all three fragments as a cyclic peptide
powder, and HRESIMS supported a molecular formula of
H
3
H
1
C H N O , requiring 15 degrees of unsaturation. The H
H
51 84 10 12
whose final structure was revealed to be cyclo [-N-Me-Thr-Val-
NMR spectrum was very similar to that of 1 and indicated 3
5
7
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Table 1. NMR Spectroscopic Data for Auyuittuqamide A in
Phe H-21 (δH 2.82) to Ile-1 H-7 (δH 4.59) confirmed the
position of the new Ile residue. The identity and sequence of
the other amino acids was confirmed by NMR analysis and
tandem mass spectrometry to be identical to 1. Therefore 3
was assigned as cyclo [-N-Me-Thr-Ile-N-Me-Phe-Gly-Ile-Ser-
Val-N-Me-Val-Gly-Leu-].
1
13
DMSO-d ( H 600 MHz, C 151 MHz)
6
position δC, type
δH (J in Hz) position δC, type
δH (J in Hz)
N-Me-
Thr
Ser
1
2
3
3
169.0, C
29
30
30-NH
31
170.2, C
55.2, CH 4.60, m
8.57, d (7.2)
Auyuittuqamide D (4) (Table S3) was obtained as a white
powder, and HRESIMS supported a molecular formula of
61.7, CH 5.04, d (9.7)
62.9, CH 3.89, m
4.66
1
C H N O , requiring 15 degrees of unsaturation. The H
5
2
86 10 12
-OH
60.7, CH2 3.67, dd
NMR spectrum was very similar to that of 3 and indicated 4
differed by the presence of a methylene group, which
corresponded to the replacement of the final Val residue
with an Ile residue. HMBC correlations from Ile-3 NH-34 (δH
(
10.0, 7.4)
4
5
20.5,
CH3
30.6,
CH3
0.89, d (6.1)
3.15, s
3.48, dd
(10.0, 7.8)
31-OH
4.86, s
8
.85) to Ser C-30 (δ 170.0) and ROESY correlations from N-
C
Val1
6
Val2
32
33
33-NH
34
Me-Val H -44 (δ 3.27) to Ile-3 H-34 (δ 4.69) confirmed the
3
H
H
171.6, C
52.9, CH 4.48, m
8.70, d (9.4)
30.7, CH 1.90, m
171.6, C
54.1, CH 4.53, m
8.91, d (9.8)
30.0, CH 2.01, m
19.5, CH3 0.84, m
position of the Ile. The identity and sequence of the remaining
amino acids were confirmed by NMR analysis and tandem
mass spectrometry to be identical to 3. Therefore 4 was
assigned as cyclo [-N-Me-Thr-Ile-N-Me-Phe-Gly-Ile-Ser-Ile-N-
Me-Val-Gly-Leu-].
7
7
8
9
-NH
19.3,
CH3
0.78, m
35
Amino acid configurations of 1−4 were determined by
1
0
17.6,
CH3
0.73, d (6.7)
36
18.1, CH3 0.83, m
11
Marfey’s analysis. Compounds 1−4 were hydrolyzed with 6
N-Me-
Phe
N-Me-
Val
M HCl and treated with 1-fluoro-2,4-dinitrophenyl-5-L-alanine
amide (L-FDAA). The hydrosylate was analyzed by LC-HRMS
and compared to L-DAA-derivatized amino acid standards.
Due to a lack of commercially available N-Me-D-Thr, an
analytical standard was prepared from Fmoc-N-Me-D-Thr-
1
1
1
2
169.9, C
66.6, CH 3.93, dd (10.3, 38
.1)
37
169.5, C
70.2, CH 3.30, m
4
1
3
33.9,
CH2
3.33, m
39
27.5, CH 2.50, m
(
tbu)-OH. A lack of availability of a commercial standard of N-
Me-D-allo-Thr meant this stereocenter was unable to be
resolved in the final structure. Additionally, due to a lack of
separation of L-Ile and L-allo-Ile by LC-HRMS using a C18
stationary phase, the configuration at the β-carbon remains
ambiguous.
2
.97, dd (14.0, 40
0.3)
21.8, CH3 1.04, d (6.6)
1
1
1
4
5/19
138.9, C
128.3,
CH
129.2,
CH
126.3,
CH
41
42
19.3, CH3 0.83, m
40.0, CH3 3.25, s
7.28, m
7.23, m
7.21, m
2.77, s
1
1
2
6/18
Compounds 1−4 were tested for cytotoxic activity against
the breast cancer cell lines MCF-7 and HTB-26 as well as
against a human epithelial keratinocyte cell line but were
inactive (IC50 > 10 μM, Table S4). No antimicrobial activity
was observed for 1−4 when tested up to 128 μM.
Gly2
7
0
39.2,
CH3
43
168.3, C
4
4
43.0, CH2 3.84, m
3.36, m
Auyuittuqamides A−D represent new members within the
cyclic decapeptide family. The isolation of cyclic decapeptides
is quite rare, and only a few examples have been reported from
Gly1
2
2
1
2
167.7, C
42.8,
CH2
44-NH
7.45, m
12,13
14−16
3.79, dd (16.9,
4.8)
microorganisms including fungi,
bacteria,
and cyano-
17
bacteria. These previously reported cyclic peptides have
limited structural similarity to the auyuittuqamides, with all
previously reported examples containing proline residues,
which impart greater structural rigidity to these compounds
than with the auyuittuqamides. The presence of multiple N-
methylated amino acids within the auyuittuqamides is unique
within the decapeptide family and has not been previously
reported for fungal cyclic decapeptides. Within this family, only
singular N-methylated amino acids have been reported, as is
3
.17, m
Leu
45
2
2-NH
7.76, t (5.5)
173.4, C
46.3, CH 4.91, m
7.46, m
40.5, CH2 1.65, m
1.17, m
23.8, CH 1.63, m
23.2, CH3 0.82, m
21.8, CH3 0.84, m
4
6
Ile
46-NH
47
2
2
2
2
2
3
4
171.7, C
54.9, CH 4.42, m
7.44, m
37.4, CH 1.84, m
4-NH
5
6
48
49
50
23.6,
CH2
1.46, m
17
the case with calophycin and the minutissamides, both
1
8
isolated from a cyanobacteria. The isolation of the
auyuittuqamides represents the first report of fungal N-
methylated cyclic decapeptides and highlights Canada’s arctic
as a resource for the discovery of new and distinct natural
products.
1
.20, m
2
7
8
10.5,
CH3
15.0,
CH3
0.77, m
2
0.81, m
was an analogue of 1 that differed by the presence of a
methylene group. Analysis of the COSY and TOCSY spectra
indicated that one of the Val residues was replaced by an Ile
EXPERIMENTAL SECTION
■
General Experimental Procedures. Optical rotations were
measured on a Rudolph Autopol III polarimeter using a 50 mm
microcell (1.2 mL). Infrared spectra were recorded using attenuated
total reflectance, on a Thermo Nicolet 6700 FT-IR spectrometer.
residue. HMBC correlations from Ile-1 NH-7 (δ 8.63) to N-
H
Me-Thr C-1 (δ 168.8) and ROESY correlations from N-Me-
C
5
8
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Article
+
NMR spectra were obtained on a Bruker Avance III NMR
spectrometer ( H: 600 MHz, C: 151 MHz) equipped with a 5 mm
data, Table 1; HRESIMS m/z 1015.6201 [M + H] , (calcd for
C H N O , 1015.6187, Δ 1.38 ppm).
1
13
5
0
83 10 12
2
3
cryoprobe. All chemical shifts (δ) are referenced to the DMSO-d
Auyuittuqamide B (2). White powder; [α]
−4.9 (c 0.1,
6
D
1
13
residual solvent peaks [ H (DMSO-d ): 2.50 ppm; C (DMSO-d ):
MeOH); UV (MeOH) λmax 222 nm; IR (film) νmax 3282, 2960,
6
6
−
1 1
3
9.51 ppm].
1632, 1547, 1470, 1417, 1386, 1350, 1205, 1138, 1026 cm ; H and
C NMR data, Table 1; HRESIMS m/z 1001.6013 [M + H] (calcd
1
3
+
LC-HRMS of compounds and extracts was carried out with an ESI-
HRMS Exactive (Thermo Scientific) operating in positive mode with
a resolution of 30 000, monitoring a mass range from 190 to 2000
amu. Chromatography was carried out using a Core−Shell 100 Å C18
column (Phenomenex, Kinetex, 1.7 μm 50 × 2.1 mm) using a linear
for C H NO 1001.6030, Δ 1.70 ppm).
4
9
81
5,
2
3
Auyuittuqamide C (3). White powder; [α]
−1.6 (c 0.1,
D
MeOH); UV (MeOH) λmax 222 nm; IR (film) ν
3282, 2964,
max
−
1
1
13
1632, 1547, 1467, 1417, 1386, 1209, 1112 cm ; H and C NMR
solvent gradient from 95% H O/0.1% formic acid (solvent A):5%
+
2
data, Table 1; HRESIMS m/z 1029.6342 [M + H] (calcd for
C H NO , 1029.6343, Δ 0.01 ppm).
CH CN/0.1% formic acid (solvent B) to 100% solvent B over 4.8 min
3
5
1
85
4
−
1
followed by a hold for 3.2 min. A flow rate of 500 μL min and 10 μL
injection volume were used. Eluant was detected by ESIMS, ELSD,
and UV 200−600 nm.
23
Auyuittuqamide D (4). White powder; [α]
−1.8 (c 0.1,
D
MeOH); UV (MeOH) λmax 222 nm; IR (film) ν
3273, 2963,
max
−1
1
13
1
629, 1548, 1465, 1417, 1112, 1016 cm ; H and C NMR data,
Direct infusion (MS/MS analysis) high-resolution mass spectrom-
etry analysis was carried out on an LTQ Orbitrap Velos mass
spectrometer (Thermo Scientific) using an ESI ion source operating
in positive mode with a resolution of 30 000, monitoring a mass range
from 150 to 1000 amu. Selected ions were fragmented using a
collision-induced dissociation energy of 35 eV.
Automated flash chromatography was performed on a Teledyne
Combiflash Rf200 using C18 RediSep columns (24 g). HPLC
purifications were carried out on a Waters auto purification system
coupled with an evaporative light-scattering detector and UV detector.
All amino acid standards were purchased from Sigma-Aldrich. All
reagents were purchased from commercial sources and used without
further purification unless otherwise stated.
+
Table 1; HRESIMS m/z 1043.6550 [M + H] (calcd for C H NO
5
2
87
5,
1
043.6500, Δ 4.79 ppm).
Preparation of N-Me-D-Thr Standard. To a vial containing
Fmoc-N-Me-D-Thr(tbu)-OH (18 mg, 47 μmol, 1 equiv) in CH Cl (1
2
2
mL), TFA (1 mL) was added dropwise and the reaction was left to
stir at rt for 16 h. The reaction was neutralized using 1 N NaOH and
concentrated under reduced pressure before being resuspended in
H O (5 mL) and extracted with EtOAc (3 × 5 mL). The organic
2
layers were combined and subjected to purification through reversed
phase flash chromatography, yielding Fmoc-N-Me-D-Thr-OH as an
off-white solid (13 mg, yield 83%).
In a vial containing Fmoc-N-Me-D-Thr-OH (13 mg, 47 μmol, 1
equiv) in DMF (800 μL) piperidine (200 μL) was added and the
reaction was left to stir at rt for 16 h. The reaction was concentrated
under reduced pressure and taken forward for derivatization without
further purification.
Isolation of Sesquicillium microsporum RKAG 186. A marine
sediment core was collected using a sterile sediment sampler
(LaMotte) at low tide at a depth of 30 cm in Frobisher Bay,
Nunavut, Canada (63.72804° N 68.41989° W) in August 2011. The
core was transferred to a sterile 50 mL conical tube, brought back to
the lab on ice, and stored at −80 °C until processing. The sediment
was passed through a series of sieves (104 and 51 μM) and separated
based on particle size in order to increase the rate of isolation of fungi
originating from vegetative propagules embedded within substrate
particles as opposed to dormant spores. The separated particles were
Amino Acid Configuration by Marfey’s Analysis. Auyuittu-
qamides A−D (0.25 mg each) were hydrolyzed by stirring in 6 M HCl
(60 μL) at 80 °C for 6 h and neutralized with 1 M NaHCO solution.
3
N-(5-Fluoro-2,4-dinitrophenyl-5)-L-alaninamide (FDAA, 0.4 mg in
3
3
80 μL of acetone) was added to the reaction mixture and stirred at
7 °C for 2 h. The reaction was quenched with 1 N aqueous HCl (80
μL) and dried before the addition of MeOH for analysis by LC-
HRMS. LC-HRMS analyses was conducted using a Hypersil Gold
resuspended in sterile H O containing 0.2 g/L chloramphenicol and
2
18 g/L Instant Ocean and were serially diluted (100- and 1000-fold
100 Å column (Thermo, 1.9 μm C18 50 mm × 2.1 mm) and a flow
dilutions). A 10 μL aliquot from each dilution was pipetted into each
well of a 48-well plate containing YM and cottonseed oil agar and
incubated at 4 or 22 °C for three months. Emerging fungal colonies
were purified to obtain axenic cultures of isolate RKAG 186.
Identification of the fungus was performed by observation of the
culture phenotype (both macro- and micromorphology) and
sequence homology of the ITS1-5.8S-ITS2 region (sequence data
deposited in GenBank with the accession number MW149114).
Extraction and Purification. Isolate RKAG 186 was inoculated
into 15 mL of YM liquid seed medium at 22 °C and agitated at 200
rpm for 5 days. The seed culture (200 μL) was used to inoculate the
isolate onto 150, 100 × 15 mm Petri plates containing 20 mL of solid
PDA agar and grown for 21 days at 22 °C. The solid agar cultures
were roughly cut up, pooled, and extracted with EtOAc. The extract
rate of 400 μL/min. The following method was used: 0−55 min 95%
H O/0.1% formic acid (solvent A):5% CH CN/0.1% formic acid
2
3
(solvent B) to 60% solvent A:40% solvent B, 55−57 min 60% solvent
A:40% solvent B to 100% solvent B, 57−60 min 100% solvent B.
Retention times were compared to derivatized amino acid standards
to determine the amino acid configurations. Chromatograms of
derivatized standards and hydrolysates are located within the
Supporting Information.
Antimicrobial Assays. Compounds 1−4 were tested for
antimicrobial activity according to Clinical Laboratory Standards
Institute testing standards in a 96-well plate microbroth dilution assay
19
as previously described. Compounds were tested against the human
microbial pathogens methicillin-resistant Staphyloccocus aureus ATCC
3
3591, vancomycin-resistant Enterococcus faecium EF379, Staph-
ylococcus warneri ATCC 17917, Pseudomonas aeruginosa ATCC
4210, and Candida albicans ATCC 14035. Optical density was
was evaporated to dryness and partitioned between 80% CH CN/
3
H O and 100% hexane. The CH CN layer was collected and
2
3
1
evaporated to dryness in vacuo to give a CH CN extract (138 mg).
3
recorded at Tzero and Tfinal using a Thermo Scientific Varioskan Flash
plate reader at 600 nm to determine growth inhibition after
incubation for 22 h (37 °C).
The extract was fractionated using automated medium-pressure
reversed-phase flash chromatography with a linear gradient from 20%
aqueous MeOH to 100% MeOH over 15 min on a 15.5 g C18
column (High Performance GOLD RediSep Rf) with a flow rate of 30
mL/min. The semipure fraction eluting at 9.5 min was subjected to
reversed-phase HPLC using a Gemini 110A C18 column (5 μm 250
Cytotoxicity Assays. Compounds 1−4 were tested for cytotox-
icity against adult human epidermal keratinocytes (HEKa), human
breast adenocarcinoma cells (ER −) (ATCC HTB-26), and human
breast adenocarcinoma cells (ER + ) (ATCC MCF-7) in triplicate in
×
10 mm, Phenomenex) and 20 min isocratic elution with 65%
19
aqueous CH CN (0.1% formic acid), resulting in the purification of 1
a 96-well cell culture plate as described previously. Cell viability was
determined 24 h after treatment using the redox dye Alamar Blue to
extrapolate cell viability. Fluorescence was monitored using a Thermo
Scientific Varioskan Flash plate reader at 560/12 excitation, 590 nm
emission both at time zero and 4 h after Alamar Blue addition.
3
(
4.1 mg), 2 (1.5 mg), 3 (2 mg), and 4 (3 mg).
Auyuittuqamide A (1). White powder; [α]
2
3
−3.6 (c 0.1,
D
MeOH); UV (MeOH) λmax 222 nm; IR (film) ν
1
3270, 2965,
max
−
1
1
13
627, 1546, 1418, 1340, 1292, 1112, 1018 cm ; H and C NMR
5
9
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Article
(
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ASSOCIATED CONTENT
sı Supporting Information
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The Supporting Information is available free of charge at
https://pubs.acs.org/doi/10.1021/acs.jnatprod.0c00966.
1H and 13C NMR data of 2−4, NMR spectra, LC-
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353−355.
(15) Holtzel, A.; Jack, R. W.; Nicholson, G. J.; Jung, G.; Gebhardt,
K.; Fiedler, H.-P.; Sussmuth, R. D. J. Antibiot. 2001, 54, 434−440.
HRMS profiles, MS/MS fragmentation analysis, and
Marfey’s analysis chromatograms (PDF)
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16) Erlanger, B.; Goode, L. Nature 1954, 174, 840−841.
17) Moon, S. S.; Jian, L. C.; Moore, R. E.; Patterson, G. M. J. Org.
Chem. 1992, 57, 1097−1103.
18) Kang, H.; Aleksej, K.; Qi, S.; Swanson, S.; Orjala, J. J. Nat. Prod.
2011, 74, 1597−1605.
(19) Overy, D.; Berrue,
Lanteigne, M.; Mcquilian, K.; Duffy, S.; Boland, P.; Jagannathan, R.;
Carr, G.; Vansteeland, M.; Kerr, R. Mycology 2014, 5, 130−144.
(
AUTHOR INFORMATION
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Corresponding Author
́
F.; Correa, H.; Hanif, N.; Hay, K.;
Russell G. Kerr − Department of Biomedical Sciences, Atlantic
Veterinary College, Charlottetown, PEI C1A 4P3, Canada;
Department of Chemistry, University of Prince Edward
Island, Charlottetown, PEI C1A 4P3, Canada; orcid.org/
0
000-0002-2557-4321; Phone: +1 902 566 0565;
Email: rkerr@upei.ca; Fax: +1 902 566 7445
Authors
Alyssa L. Grunwald − Department of Biomedical Sciences,
Atlantic Veterinary College, Charlottetown, PEI C1A 4P3,
Canada; orcid.org/0000-0001-9688-0003
Christopher Cartmell − Department of Chemistry, University
of Prince Edward Island, Charlottetown, PEI C1A 4P3,
Canada; orcid.org/0000-0002-8722-9187
Complete contact information is available at:
https://pubs.acs.org/10.1021/acs.jnatprod.0c00966
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
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The authors gratefully acknowledge financial support from the
Natural Sciences and Engineering Council of Canada
(
NSERC), the Canada Research Chair Program, the University
of Prince Edward Island, the Atlantic Innovation Fund,
Innovation PEI, Jeanne and Jean-Louis Levesque Foundation,
́
and Nautilus Biosciences Croda. We also acknowledge the
Nunavut Research Institute and Nunavut Tunngavik Inc. for
assistance with collections and permission to collect sediment
samples. The authors also acknowledge NMR services
provided by Dr. C. Kirby and M. Fischer (AAFC).
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