Multiheme selenoenzyme essential for elemental sulfur respiration.

Authors

Hisaaki Mihara, Takuya Yoshizawa, Yukiko Izu, Wanjiao Zhang, Masao Inoue, Nana Shimamoto, Ryuta Tobe, Riku Aono, Tatsuo Kurihara, Hiroyoshi Matsumura

Published in

Science advances. Volume 12. Issue 35. Pages eaeg2218. Aug 28, 2026. Epub Aug 26, 2026.

Abstract

Elemental sulfur reduction is a key process in anaerobic ecosystems and the global sulfur cycle. Although elemental sulfur serves as a terminal electron acceptor in microbial respiration, the molecular basis is unclear. Here, we identify a conserved multiheme cytochrome c selenoprotein essential for sulfur reduction in a sulfur-respiring bacterium. Structural and biochemical analyses show that the enzyme forms a tetramer, with each subunit containing five hemes and one selenocysteine residue. The enzyme catalyzes polysulfide reduction at an active site, where a cysteine coordinates the heme iron, while selenocysteine is essential for catalysis. Genetic analyses show that both residues are critical for sulfur respiration in vivo. These findings reveal a selenium-sulfur-dependent catalysis on a heme center for polysulfide reduction, expanding our understanding of microbial energy metabolism.

PMID:
42647610
Bibliographic data and abstract were imported from PubMed on 27 Aug 2026.

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