华南师范大学张新帅研究团队报道了麦角硫因分解代谢的肠道细菌途径的发现。相关研究成果发表在2024年12月19日出版的《美国化学会杂志》。

麦角硫因是一种来源于人类饮食的微量营养素。然而，人类肠道细菌中参与麦角硫因分解代谢的酶尚未被鉴定。

该文中，研究人员描述了这种微量营养素在肠道细菌分解代谢中的亚磺酰化途径，该途径涉及由黄嘌呤氧化还原酶家族（XOR）成员催化的前所未有的还原脱硫反应，XOR是一类含钼的黄素蛋白。值得注意的是，这是已知的第一个由XOR催化的C-S键断裂反应。

通过使用来源于人类肠道细菌Blautia producta ATCC 27340异源产生的酶进行体外重建，研究人员获得了该途径运作的证据。这种分解代谢活性使B.producta ATCC 27340能够使用麦角硫因作为替代电子受体来源。途径酶的同源物不仅存在于人类肠道细菌中，也存在于许多环境细菌中，这表明这种分解代谢策略分布广泛。

关于含硫代谢物，这一发现为人类肠道以外不同缺氧栖息地的生物地球化学硫循环提供了重要见解，此外，还为控制肠道硫化氢（H₂S）产生的新方法的设计提供了重要依据。

附：英文原文

Title: Discovery of a Gut Bacterial Pathway for Ergothioneine Catabolism

Author: Chenxi Feng, Qiongxiang Yan, Xianyi Li, Hong Zhao, Hua Huang, Xinshuai Zhang

Issue&Volume: December 19, 2024

Abstract: Ergothioneine is a diet-derived micronutrient for humans. However, enzymes involved in the catabolism of ergothioneine in human gut bacteria have not yet been identified. Herein, we characterize a sulfidogenic pathway for gut bacterial catabolism of this micronutrient, which involves an unprecedented reductive desulfurization reaction catalyzed by members of the xanthine oxidoreductase family (XOR), a class of molybdenum-containing flavoproteins. Notably, this is the first C–S bond cleavage reaction known to be catalyzed by XORs. Evidence for operation of this pathway was gained through in vitro reconstruction using heterologously produced enzymes derived from the human gut bacterium Blautia producta ATCC 27340. This catabolic activity enables B. producta ATCC 27340 to use ergothioneine as an alternative electron acceptor source. Homologues of the pathway enzymes are shown to be present not only in human gut bacteria but also in many environmental bacteria, suggesting the wide distribution of this catabolic strategy. In relation to the sulfur-containing metabolite, this discovery provides significant insight into biogeochemical sulfur cycling in diverse anoxic habitats beyond the human gut and, moreover, the design of new approaches for controlling intestinal hydrogen sulfide (H2S) production.

DOI: 10.1021/jacs.4c09350

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.4c09350