Functional methylthio-alkane reductases are widely distributed for bacterial organic sulfur acquisition.

Functional methylthio-alkane reductases are widespread across diverse bacterial taxa, enabling organic sulfur acquisition in anaerobic environments, with 100% of tested Clostridia and Bacteroidia possessing active enzymes.

• Why it matters: Understanding how bacteria acquire sulfur in sulfur-limited, anoxic habitats is crucial for ecological and biogeochemical insights, yet the distribution of key sulfur-processing enzymes remained unclear.
• What they did: Researchers synthesized and expressed MAR genes from uncultivated bacteria, confirming enzyme activity in multiple bacterial classes, and identified that MAR enzymes are present in Clostridia, Bacteroidia, and other groups, with a minimal gene set involving MarB or NifB.
• The result: The discovery that MAR enzymes rely on nitrogenase-like cofactors broadens understanding of sulfur cycling, revealing a widespread bacterial capacity to utilize volatile organic sulfur compounds in oxygen-deprived environments.