Journal Article Molecular evolution of gas cavity in [NiFeSe] hydrogenases resurrected in silico

Tamura, Takashi  ,  Tsunekawa, Naoki  ,  Nemoto, Michiko  ,  Inagaki, Kenji  ,  Hirano, Toshiyuki  ,  Sato, Fumitoshi

6p.19742 , 2016-01-28 , Nature Publishing Group
Oxygen tolerance of selenium-containing [NiFeSe] hydrogenases (Hases) is attributable to the high reducing power of the selenocysteine residue, which sustains the bimetallic Ni–Fe catalytic center in the large subunit. Genes encoding [NiFeSe] Hases are inherited by few sulphate-reducing δ-proteobacteria globally distributed under various anoxic conditions. Ancestral sequences of [NiFeSe] Hases were elucidated and their three-dimensional structures were recreated in silico using homology modelling and molecular dynamic simulation, which suggested that deep gas channels gradually developed in [NiFeSe] Hases under absolute anaerobic conditions, whereas the enzyme remained as a sealed edifice under environmental conditions of a higher oxygen exposure risk. The development of a gas cavity appears to be driven by non-synonymous mutations, which cause subtle conformational changes locally and distantly, even including highly conserved sequence regions.

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