Radical-mediated C-S bond cleavage in C2 sulfonate degradation by anaerobic bacteria

• Published in: Nature communications Vol. 10; no. 1; pp. 1609 - 11
• Main Authors: Xing, Meining, Wei, Yifeng, Zhou, Yan, Zhang, Jun, Lin, Lianyun, Hu, Yiling, Hua, Gaoqun, N. Nanjaraj Urs, Ankanahalli, Liu, Dazhi, Wang, Feifei, Guo, Cuixia, Tong, Yang, Li, Mengya, Liu, Yanhong, Ang, Ee Lui, Zhao, Huimin, Yuchi, Zhiguang, Zhang, Yan
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 08-04-2019; Nature Publishing Group; Nature Portfolio
• Subjects: 140/58; 45/77; 631/326/1320; 631/45/607; 631/535/1266; 82/16; 82/58; 82/80; 82/83; Acetaldehyde; Acetyltransferases - genetics; Acetyltransferases - isolation & purification; Acetyltransferases - metabolism; Anaerobic bacteria; Anaerobic microorganisms; Anaerobic processes; Anaerobic respiration; Bacteria; Bacterial Proteins - genetics; Bacterial Proteins - isolation & purification; Bacterial Proteins - metabolism; Bile; Bile Acids and Salts - metabolism; Bilophila - metabolism; Bilophila wadsworthia; Biodegradation; Cleavage; Degradation; Desulfovibrio - metabolism; Enzyme Assays; Gastrointestinal Microbiome - physiology; Humanities and Social Sciences; Hydrogen sulfide; Hydrogen Sulfide - metabolism; Hydrogen Sulfide - toxicity; Intestinal Mucosa - metabolism; Intestinal Mucosa - microbiology; Mercaptoethanol - analogs & derivatives; Mercaptoethanol - metabolism; Metabolic Networks and Pathways - physiology; Metabolism; Microorganisms; multidisciplinary; Organosulfonates; Recombinant Proteins - genetics; Recombinant Proteins - isolation & purification; Recombinant Proteins - metabolism; Science; Science (multidisciplinary); Structural analysis; Sulfates; Sulfite; Sulfite-reducing bacteria; Sulfonates; Sulfur; Sulfur - metabolism; Sulfur compounds; Taurine; Taurine - metabolism
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-019-09618-8

Bacterial degradation of organosulfonates plays an important role in sulfur recycling, and has been extensively studied. However, this process in anaerobic bacteria especially gut bacteria is little known despite of its potential significant impact on human health with the production of toxic H
2
S. Here, we describe the structural and biochemical characterization of an oxygen-sensitive enzyme that catalyzes the radical-mediated C-S bond cleavage of isethionate to form sulfite and acetaldehyde. We demonstrate its involvement in pathways that enables C2 sulfonates to be used as terminal electron acceptors for anaerobic respiration in sulfate- and sulfite-reducing bacteria. Furthermore, it plays a key role in converting bile salt-derived taurine into H
2
S in the disease-associated gut bacterium
Bilophila wadsworthia
. The enzymes and transporters in these anaerobic pathways expand our understanding of microbial sulfur metabolism, and help deciphering the complex web of microbial pathways involved in the transformation of sulfur compounds in the gut.
The C2 sulfonates taurine and isethionate are also present in the anaerobic mammalian gut, where they are converted into toxic H
2
S by sulfate and sulfite-reducing bacteria. Here the authors characterise the O
2
-sensitive enzyme IseG that catalyzes the C-S bond cleavage of isethionate and show that IseG also plays a key role in converting taurine into H
2
S in
Bilophila wadsworthia
.