通过生物信息学基因聚类分析和 Ajudazol B 的不对称正石化策略全合成全立体化学测定 Ajudazol A 和 B
摘要:
报告了强效呼吸链抑制剂阿达唑 A 和 B 的立体化学测定以及阿达唑 B 的全合成。构型分配完全基于对含羟基立体中心的酮还原酶结构域和含甲基立体中心的第一个预测性烯酰还原酶比对之一的生物合成基因簇分析。通过创新的不对称正锂化策略、模块化恶唑形成和后期 Z,Z 选择性 Suzuki 偶联,对具有挑战性的异色满酮立体三联体进行了短期立体选择性方法,从而对预测的立体化学进行了明确的证明。
D-ALA-D-ALA-BASED DIPEPTIDES AS TOOLS FOR IMAGING PEPTIDOGLYCAN BIOSYNTHESIS
申请人:INDIANA UNIVERSITY RESEARCH AND TECHNOLOGY CORPORATION
公开号:US20160222430A1
公开(公告)日:2016-08-04
Disclosed herein are compositions for assessing peptidoglycan biosynthesis in bacteria using modified dipeptides containing a bioorthogonal tag and applying novel post-labeling methods to label the bioorthogonal tag. The resultant, labeled peptidoglycan structures are amenable for identifying bacteria by microscopic visualization.
作者:Stephen Birkett、Danny Ganame、Bill C. Hawkins、Sébastien Meiries、Tim Quach、Mark A. Rizzacasa
DOI:10.1021/ol200331u
日期:2011.4.15
The totalsynthesis of a stereoisomer of 8-deshydroxyajudazol B (4), the putative biosynthetic intermediate of the ajudazols A (1) and B (2), is described. The key steps in the synthesis included an intramolecular Diels−Alder (IMDA) reaction to secure the isochromanone fragment, a novel selective acylation/O,N-shift to give a hydroxyamide which was cyclized to the oxazole and a high yielding Sonogashira
Engineering Orthogonal Polypeptide GalNAc-Transferase and UDP-Sugar Pairs
作者:Junwon Choi、Lauren J. S. Wagner、Suzanne B. P. E. Timmermans、Stacy A. Malaker、Benjamin Schumann、Melissa A. Gray、Marjoke F. Debets、Megumi Takashima、Jase Gehring、Carolyn R. Bertozzi
DOI:10.1021/jacs.9b04695
日期:2019.8.28
O-Linked alpha-N-acetylgalactosamine (O-GalNAc) glycans constitute a major part of the human glycome. They are difficult to study because of the complex interplay of 20 distinct glycosyltransferase isoenzymes that initiate this form of glycosylation, the polypeptide N-acetylgalactosaminyltransferases (GalNAc-Ts). Despite proven disease relevance, correlating the activity of individual GalNAc-Ts with biological function remains challenging due to a lack of tools to probe their substrate specificity in a complex biological environment. Here, we develop a "bump-hole" chemical reporter system for studying GalNAc-T activity in vitro. Individual GalNAc-Ts were rationally engineered to contain an enlarged active site (hole) and probed with a newly synthesized collection of 20 (bumped) uridine diphosphate N-acetylgalactosamine (UDP-GalNAc) analogs to identify enzyme-substrate pairs that retain peptide specificities but are otherwise completely orthogonal to native enzyme-substrate pairs. The approach was applicable to multiple GalNAc-T isoenzymes, including GalNAc-T1 and -T2 that prefer nonglycosylated peptide substrates and GalNAcT-10 that prefers a preglycosylated peptide substrate. A detailed investigation of enzyme kinetics and specificities revealed the robustness of the approach to faithfully report on GalNAc-T activity and paves the way for studying substrate specificities in living systems.