Niu Weijing, Liu Jiaqi, Duan Yuwei, Zhong Lin, Pang Linlin, Zhong Guannan, Zhang Youming, Bian Xiaoying
Helmholtz International Lab for Anti-Infectives, Shandong University-Helmholtz Institute of Biotechnology, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, Shandong, 266237, China.
Chemistry. 2024 Dec 10;30(69):e202402763. doi: 10.1002/chem.202402763. Epub 2024 Oct 31.
Non-ribosomal peptide synthetases (NRPSs) and their tailored enzymes have diverse biological functions. In this study, we investigated the biosynthesis and function of chitinimides, which belong to the non-ribosomal peptide (NRP) subfamily featuring a pyrrolidine-containing part (X part) connected to the polypeptide chain via an ester bond. A conserved gene cassette, chmHIJK, is responsible for oxyacylation of the pyrrolidine moiety in the X part. The thioesterase (TE) domain of ChmC (ChmC-TE) catalyzes transesterification reactions with a free X part or methanol as a nucleophilic reagent to form different chitinimides. The crucial amino acid residues in the ChmC-TE domains responsible for the specific recognition of the X part were identified, and they were conserved in all the biosynthetic pathways of this NRP subfamily to form a signature motif, YNHNR, suggesting a special type of TE domain in NRPSs. Chitinimides demonstrate the biological function of promoting the swarming ability of the native producer. This study provides deep insights into the biosynthesis of this special NRP subfamily, and shows that the special TE domain could be used to generate diverse NRPs by combinatorial biosynthesis.
非核糖体肽合成酶（NRPSs）及其修饰酶具有多种生物学功能。在本研究中，我们研究了几丁质亚胺的生物合成和功能，几丁质亚胺属于非核糖体肽（NRP）亚家族，其特征是含有一个通过酯键连接到多肽链上的含吡咯烷部分（X部分）。一个保守的基因盒chmHIJK负责X部分中吡咯烷部分的氧酰化。ChmC的硫酯酶（TE）结构域（ChmC-TE）催化与游离X部分或甲醇作为亲核试剂的酯交换反应，以形成不同的几丁质亚胺。确定了ChmC-TE结构域中负责特异性识别X部分的关键氨基酸残基，并且它们在该NRP亚家族的所有生物合成途径中都是保守的，以形成一个特征基序YNHNR，这表明NRPSs中存在一种特殊类型的TE结构域。几丁质亚胺展示了促进天然产生菌群体运动能力的生物学功能。本研究为这个特殊的NRP亚家族的生物合成提供了深入见解，并表明这种特殊的TE结构域可用于通过组合生物合成产生多种NRP。
