6U8Y

Structure of the membrane-bound sulfane sulfur reductase (MBS), an archaeal respiratory membrane complex

Summary for 6U8Y

• Entry DOI: 10.2210/pdb6u8y/pdb
• EMDB information: 20692
• Descriptor: Monovalent cation/H+ antiporter subunit E, NADH dehydrogenase subunit C, NADH dehydrogenase subunit D, ... (14 entities in total)
• Functional Keywords: cryoem, membrane protein, respiratory system
• Biological source: Pyrococcus furiosus COM1; More
• Total number of polymer chains: 26
• Total formula weight: 717706.79

Authors

Yu, H.J.,Li, H.L. (deposition date: 2019-09-06, release date: 2020-09-09, Last modification date: 2025-05-28)

Primary citation

Yu, H.,Haja, D.K.,Schut, G.J.,Wu, C.H.,Meng, X.,Zhao, G.,Li, H.,Adams, M.W.W.
Structure of the respiratory MBS complex reveals iron-sulfur cluster catalyzed sulfane sulfur reduction in ancient life.
Nat Commun, 11:5953-5953, 2020

PubMed Abstract: Modern day aerobic respiration in mitochondria involving complex I converts redox energy into chemical energy and likely evolved from a simple anaerobic system now represented by hydrogen gas-evolving hydrogenase (MBH) where protons are the terminal electron acceptor. Here we present the cryo-EM structure of an early ancestor in the evolution of complex I, the elemental sulfur (S)-reducing reductase MBS. Three highly conserved protein loops linking cytoplasmic and membrane domains enable scalable energy conversion in all three complexes. MBS contains two proton pumps compared to one in MBH and likely conserves twice the energy. The structure also reveals evolutionary adaptations of MBH that enabled S reduction by MBS catalyzed by a site-differentiated iron-sulfur cluster without participation of protons or amino acid residues. This is the simplest mechanism proposed for reduction of inorganic or organic disulfides. It is of fundamental significance in the iron and sulfur-rich volcanic environments of early earth and possibly the origin of life. MBS provides a new perspective on the evolution of modern-day respiratory complexes and of catalysis by biological iron-sulfur clusters.

PubMed: 33230146
DOI: 10.1038/s41467-020-19697-7

Experimental method

ELECTRON MICROSCOPY (4 Å)