Conformational protection of molybdenum nitrogenase by Shethna protein II.

ABSTRACT: The oxygen-sensitive molybdenum-dependent nitrogenase of Azotobacter vinelandii is protected from oxidative damage by a reversible 'switch-off' mechanism¹. It forms a complex with a small ferredoxin, FeSII (ref. ²) or the 'Shethna protein II'³, which acts as an O₂ sensor and associates with the two component proteins of nitrogenase when its [2Fe:2S] cluster becomes oxidized^4,5. Here we report the three-dimensional structure of the protective ternary complex of the catalytic subunit of Mo-nitrogenase, its cognate reductase and the FeSII protein, determined by single-particle cryo-electron microscopy. The dimeric FeSII protein associates with two copies of each component to assemble a 620 kDa core complex that then polymerizes into large

SUBMITTER: Franke P 

PROVIDER: S-EPMC11754109 | biostudies-literature | 2025 Jan

REPOSITORIES: biostudies-literature