Shao Ning, Ma Xueyang, Zhang Ying-Ying, Yang Donghui, Ma Ming, Tang Gong-Li
State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China.
Acta Pharm Sin B. 2023 Mar;13(3):1318-1325. doi: 10.1016/j.apsb.2022.10.005. Epub 2022 Oct 7.
Dihydrofolate reductase (DHFR), a housekeeping enzyme in primary metabolism, has been extensively studied as a model of acid-base catalysis and a clinic drug target. Herein, we investigated the enzymology of a DHFR-like protein SacH in safracin (SAC) biosynthesis, which reductively inactivates hemiaminal pharmacophore-containing biosynthetic intermediates and antibiotics for self-resistance. Furthermore, based on the crystal structure of SacH-NADPH-SAC-A ternary complexes and mutagenesis, we proposed a catalytic mechanism that is distinct from the previously characterized short-chain dehydrogenases/reductases-mediated inactivation of hemiaminal pharmacophore. These findings expand the functions of DHFR family proteins, reveal that the common reaction can be catalyzed by distinct family of enzymes, and imply the possibility for the discovery of novel antibiotics with hemiaminal pharmacophore.
二氢叶酸还原酶（DHFR）是初级代谢中的一种管家酶，作为酸碱催化模型和临床药物靶点已被广泛研究。在此，我们研究了在沙弗拉辛（SAC）生物合成中一种类似DHFR的蛋白质SacH的酶学性质，它能还原失活含半缩醛胺药效团的生物合成中间体和抗生素以实现自我抗性。此外，基于SacH-NADPH-SAC-A三元复合物的晶体结构和诱变实验，我们提出了一种不同于先前表征的短链脱氢酶/还原酶介导的半缩醛胺药效团失活的催化机制。这些发现扩展了DHFR家族蛋白的功能，揭示了常见反应可由不同酶家族催化，并暗示了发现含半缩醛胺药效团新型抗生素的可能性。
