Nonribosomal peptide synthetases (NRPSs) are large multidomain enzymes for the synthesis of a variety of bioactive peptides in a modular and pipelined fashion. Here, we investigated how the condensation (C) domain and the adenylation (A) domain cooperate with each other for the efficient catalytic activity in microcystin NRPS modules. We solved two crystal structures of the microcystin NRPS modules, representing two different conformations in the NRPS catalytic cycle. Our data reveal that the dynamic interaction between the C and the A domains in these modules is mediated by the conserved “RXGR” motif, and this interaction is important for the adenylation activity. Furthermore, the “RXGR” motif-mediated dynamic interaction and its functional regulation are prevalent in different NRPSs modules possessing both the A and the C domains. This study provides new insights into the catalytic mechanism of NRPSs and their engineering strategy for synthetic peptides with different structures and properties.

中文翻译：

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非核糖体肽合成酶的模块化催化活性取决于腺苷酸化和缩合结构域之间的动态相互作用


非核糖体肽合成酶 (NRPS) 是大型多域酶，用于以模块化和流水线方式合成各种生物活性肽。在这里，我们研究了缩合 (C) 结构域和腺苷酸化 (A) 结构域如何相互配合以实现微囊藻毒素 NRPS 模块的有效催化活性。我们解析了微囊藻毒素 NRPS 模块的两种晶体结构，代表 NRPS 催化循环中的两种不同构象。我们的数据表明，这些模块中 C 和 A 结构域之间的动态相互作用是由保守的“RXGR”基序介导的，这种相互作用对于腺苷酸化活性非常重要。此外，“RXGR”基序介导的动态相互作用及其功能调节在同时具有 A 和 C 结构域的不同 NRPS 模块中普遍存在。这项研究为NRPS的催化机制及其合成具有不同结构和性质的肽的工程策略提供了新的见解。