Structural basis of the redox switches in the NAD + -reducing soluble [NiFe]-hydrogenase

• DOI: 10.1126/science.aan4497
• Publication Date: 2017-08-31T17:45:23Z
• Authors: Y. Shomura; M. Taketa; H. Nakashima; H. Tai; H. Nakagawa; Y. Ikeda; M. Ishii; Y. Igarashi; H. Nishihara; K.-S. Yoon; S. Ogo; S. Hirota; Y. Higuchi
• Keywords: Hydrogenase; Oxidation reduction

NAD+ (oxidized form of NAD:nicotinamide adenine dinucleotide)-reducing soluble [NiFe]-hydrogenase (SH) is phylogenetically related to NADH (reduced NAD+):quinone oxidoreductase (complex I), but the geometrical arrangements subunits and Fe-S clusters are unclear. Here, we describe crystal structures SH in oxidized reduced states. The cluster arrangement similar that complex I, orientation not, which supports hypothesis evolved as prebuilt modules. active site includes a six-coordinate Ni, unprecedented for hydrogenases, whose coordination geometry would prevent O2 from approaching. In state showing normal structure without physiological electron acceptor, flavin mononucleotide cofactor dissociated, may be caused by oxidation change nearby suppress production reactive oxygen species.