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Publication Abstract from PubMed

Octaheme nitrite reductase from the haloalkaliphilic bacterium Thioalkalivibrio paradoxus was isolated and characterized. A comparative structural and functional analysis of two homologous octaheme nitrite reductases from closely related Thioalkalivibrio species was performed. It was shown that both enzymes have similar catalytic properties due to high structural similarity. Both enzymes are characterized by specific structural features distinguishing them from pentaheme cytochrome c nitrite reductases, such as the Tyr-Cys bond in the active site, the hexameric structure resulting in the formation of a void space inside the hexamer, and the product channel that opens into the void interior space of the hexamer. It is suggested that these specific structural features are responsible for the higher nitrite reductase activity, the greater preference for nitrite than sulfite as a substrate, and the wider pH range of the catalytic activity of octaheme nitrite reductases compared to pentaheme homologues. (c) 2012 The Authors Journal compilation (c) 2012 FEBS.

Comparative structural and functional analysis of two octaheme nitrite reductases from closely related Thioalkalivibrio species.,Tikhonova T, Tikhonov A, Trofimov A, Polyakov K, Boyko K, Cherkashin E, Rakitina T, Sorokin D, Popov V FEBS J. 2012 Aug 30. doi: 10.1111/j.1742-4658.2012.08811.x. PMID:22935005^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.