prenylation is an outstanding modification in alkaloid and peptide biosynthesis, but its enzymaticbasis has remained elusive. We report the isolation of argicyclamides, a new class of cyanobactins with unique mono- and bis-prenylations on guanidine moieties, from Microcystis aeruginosa NIES-88. The genetic basis of argicyclamide biosynthesis was established by the heterologous expression and in vitro characterization
Application of 3D NMR for Structure Determination of Peptide Natural Products
作者:Fan Zhang、Navid Adnani、Emmanuel Vazquez-Rivera、Doug R. Braun、Marco Tonelli、David R. Andes、Tim S. Bugni
DOI:10.1021/acs.joc.5b01486
日期:2015.9.4
in NMR, structuredetermination is often slow and constitutes a bottleneck in natural products discovery. Removal of this bottleneck would greatly improve the throughput for antibiotic discovery as well as other therapeutic areas. Overall, faster structure methods for structuredetermination will serve the natural products community in a broad manner. This report describes the first application of
尽管核磁共振技术取得了进步,但结构测定通常很慢,并且构成了天然产物发现的瓶颈。消除这一瓶颈将大大提高抗生素发现以及其他治疗领域的吞吐量。总体而言,用于结构测定的更快的结构方法将以广泛的方式服务于天然产物界。本报告描述了 3D NMR 首次应用于阐明两种具有新颖结构的微生物产生的肽天然产物。这些方法具有成本效益,并且大大提高了对所提出结构的信心。
New cytotoxic callipeltins from the Solomon Island marine sponge Asteropus sp.
Four new callipeltin A derivatives (N–Q) have been isolated from the Solomon Island marinesponge Asteropus sp. Their structures were established by spectroscopic techniques followed by acid hydrolysis and derivatisation of the free amino acids, and subsequent LCMS analysis of the derivatives. The compounds were evaluated for their activity against cancer cell lines A2058 (melanoma), HT-29 (colorectal
Two novel siderophores, chlorocatechelins A and B, were isolated from a culture broth of Streptomyces sp. Their structures were determined by spectroscopic analysis and degradation study. They contain chloro-substituted catecholate that has not been reported in natural products, whereas this group was conjugated to guanidine to form acylguanidine in chlorocatechelin A. This acylguanidine decomposed in weakly acidic solutions to furnish a less potent siderophore chlorocatechelin B. Chemical and biological insights into acylguanidine are also discussed.
作者:Zhibin Liang、Analia Sorribas、Florian J. Sulzmaier、Jorge I. Jiménez、Xin Wang、Thomas Sauvage、Wesley Y. Yoshida、Guangyi Wang、Joe W. Ramos、Philip G. Williams
DOI:10.1021/jo200241h
日期:2011.5.20
An extensive study of the secondary metabolites produced by a new Sticta sp. of lichen has led to the isolation of three new compounds containing the 4-amino-3-hydroxy-5-phenylpentanoic acid residue (Ahppa). The structures of stictamides A-C (1-3) were assigned by 2D NMR spectroscopic and chemical methods. Due to extensive epimerization of the Ahppa residue observed after acid hydrolysis, the configuration of this unit was deduced through conversion of 1 to an appropriate derivative and application of our recently developed statine NMR database. Evaluation of stictamide A against a panel of disease-relevant proteases showed that it inhibited MMP12 at 2.3 mu M and significantly reduced invasion in the human glioma cell line U87MG. Docking studies suggest that stictamide A inhibits MMP12 by a non-zinc-binding mechanism.