| Literature DB >> 28761094 |
Wei-Feng Xu1,2, Xue-Mei Hou2,3, Fei-Hua Yao1, Na Zheng1, Jun Li1, Chang-Yun Wang2,3, Rui-Yun Yang4, Chang-Lun Shao5,6.
Abstract
Two new cyclopentapeptides, xylapeptide A (1) with an uncommon L-pipecolinic acid moiety, and xylapeptide B (2) having a common L-proline residue were identified from an associated fungus Xylaria sp. isolated from the Chinese medicinal plant Sophora tonkinensis. Their planar structures were elucidated by a comprehensive analysis of NMR and MS spectroscopic spectra. The absolute configurations were determined by Marfey's method and single-crystal X-ray diffraction (Cu Kα) analysis. Xylapeptide A (1) is the first example of cyclopentapeptide with L-Pip of terrestrial origin and showed strong antibacterial activity against Bacillus subtilis and B. cereus with MIC value of 12.5 μg/mL.Entities:
Mesh:
Substances:
Year: 2017 PMID: 28761094 PMCID: PMC5537251 DOI: 10.1038/s41598-017-07331-4
Source DB: PubMed Journal: Sci Rep ISSN: 2045-2322 Impact factor: 4.379
Figure 1Chemical structures of xylapeptides A (1) and B (2).
NMR data of xylapeptide A (1)a.
| Amino acid | Position |
|
| COSY | HMBC |
|---|---|---|---|---|---|
|
| 1 | 170.2 | |||
| 2 | 64.2 | 4.34, d (10.7) | H-3 | C-1/3/10/25 | |
| 3 | 34.3 | 2.82, dd (13.5, 10.7) 3.62, d (13.5) | H-2 | C-2/4/5/9 | |
| 4 | 138.5 | ||||
| 5/9 | 129.5 | 7.17, d (7.2) | |||
| 6/8 | 129.1 | 7.31, t (7.2) | C-4 | ||
| 7 | 127.2 | 7.26, m | |||
| 10 | 31.6 | 2.97, s | |||
| Val | 11 | 171.8 | |||
| 12 | 59.0 | 4.14, t (9.0) | H-13,NH | C-1/11/13/14 | |
| 13 | 29.0 | 2.23, m | H-2 | ||
| 14 | 18.7 | 0.96, d (6.8) | |||
| 15 | 19.7 | 0.98, d (6.8) | |||
| NH | 7.45, d (9.0) | H-12 | C-1/12 | ||
| Ala | 16 | 172.8 | |||
| 17 | 47.5 | 4.61, m | H-18, NH | C-18 | |
| 18 | 14.2 | 1.32, d (6.8) | H-17 | C-16/17 | |
| NH | 6.13,d (8.2) | H-17 | C-11 | ||
| Leu | 19 | 172.6 | |||
| 20 | 48.1 | 4.74, t (8.4) | NH | C-19/21 | |
| 21 | 41.1 | 1.25, m 1.55, m | |||
| 22 | 24.8 | 1.59, m | |||
| 23 | 21.5 | 0.88, d (6.3) | C-21/22 | ||
| 24 | 23.3 | 0.89, d (6.3) | |||
| NH | 7.11, d (8.4) | H-20 | C-16 | ||
| Pip | 25 | 171.8 | |||
| 26 | 57.0 | 2.44, d (10.4) | H-27 | C-25/27 | |
| 27 | 28.5 | 0.70, m 1.40, m | H-28 | ||
| 28 | 23.2 | 0.79, m 1.57, m | H-29 | ||
| 29 | 25.2 | 1.31, m 1.55, m | H-30 | ||
| 30 | 47.4 | 2.73, dd (13.3, 9.0) 3.88, d (13.3) | H-29 | C-19 |
aMeasured at 500 MHz for 1H NMR and 125 MHz for 13C NMR in CDCl3.
Figure 2(1) the subunits of 1 derived from 2D NMR data and (2) the assemble of the subunits by key HMBC correlations.
Figure 3X-ray crystallographic analysis of (1 and 2).
NMR data of xylapeptide B (2)a.
| Amino acid | Position |
|
| COSY | HMBC |
|---|---|---|---|---|---|
|
| 1 | 170.1 | |||
| 2 | 64.9 | 4.93, dd (12.1, 2.6) | H-3 | C-1/3/4/10 | |
| 3 | 34.1 | 2.83, dd (14.2, 12.1) 3.60, dd (14.2, 2.6) | H-2 | C-2/4/5/9 | |
| 4 | 138.4 | ||||
| 5/9 | 129.4 | 7.10, d (7.2) | H-6/8 | ||
| 6/8 | 128.9 | 7.26, t (7.2) | H-5/9 | ||
| 7 | 126.8 | 7.20, t (7.2) | |||
| 10 | 30.8 | 2.93, s | C-2/25 | ||
| Val | 11 | 171.1 | |||
| 12 | 60.0 | 4.14, t (8.2) | H-13, NH | C-11/13/14 | |
| 13 | 30.2 | 2.23, qd (13.5, 6.8) | H-12/14 | C-11/12/14 | |
| 14 | 18.6 | 0.96, d (6.8) | H-13 | C-12/13 | |
| 15 | 19.8 | 0.95, d (6.8) | H-13 | C-12/13 | |
| NH | 8.23, d (8.2) | H-12 | C-1/11/12 | ||
| Ala | 16 | 174.6 | |||
| 17 | 48.3 | 4.56, dq (8.5, 6.9) | H-18, NH | C-11/16/18 | |
| 18 | 14.8 | 1.29, d (6.9) | H-17 | C-16/17 | |
| NH | 6.14, d (8.5) | H-17 | C-11/17/18 | ||
| Leu | 19 | 170.6 | |||
| 20 | 52.1 | 4.32, td (10.2, 3.9) | H-21, NH | C-19/21/23 | |
| 21 | 38.4 | 1.41, m | H-2 | C-19/20/22/23 | |
| 22 | 25.2 | 1.72, m | H-5 | C-20/21/23 | |
| 23 | 21.1 | 0.88, d (6.5) | H-4 | C-20/22 | |
| 24 | 23.3 | 0.90, d (6.5) | H-4 | C-20/22 | |
| NH | 6.46, d (10.2) | H-2 | C-16/21 | ||
| Pro | 25 | 172.6 | |||
| 26 | 56.4 | 3.88, dd (9.2, 6.4) | H-27 | C-19/25/27 | |
| 27 | 28.3 | 1.45, m 0.52, dt (6.4, 3.9) | H-26/28 | C-25/28/29 | |
| 28 | 25.7 | 1.49, m 1.89, m | H-29 | C-26/27 | |
| 29 | 46.2 | 3.33, ddd (14.0, 9.7, 6.7) 3.48, dd (14.0, 6.7) | H-28 | C’26/27/28 |
aMeasured at 400 MHz for 1H NMR and 100 MHz for 13C NMR in CDCl3.
Figure 41H-1H COSY and HMBC correlations of 2.