1yqw
From Proteopedia
Structure of the Oxidized Unready Form of Ni-Fe Hydrogenase
Overview
[NiFe] hydrogenases catalyze the reversible heterolytic cleavage of molecular hydrogen. Several oxidized, inactive states of these enzymes are known that are distinguishable by their very different activation properties. So far, the structural basis for this difference has not been understood because of lack of relevant crystallographic data. Here, we present the crystal structure of the ready Ni-B state of Desulfovibrio fructosovorans [NiFe] hydrogenase and show it to have a putative mu-hydroxo Ni-Fe bridging ligand at the active site. On the other hand, a new, improved refinement procedure of the X-ray diffraction data obtained for putative unready Ni-A/Ni-SU states resulted in a more elongated electron density for the bridging ligand, suggesting that it is a diatomic species. The slow activation of the Ni-A state, compared with the rapid activation of the Ni-B state, is therefore proposed to result from the different chemical nature of the ligands in the two oxidized species. Our results along with very recent electrochemical studies suggest that the diatomic ligand could be hydro-peroxide.
About this Structure
1YQW is a Protein complex structure of sequences from Desulfovibrio fructosovorans. Full crystallographic information is available from OCA.
Reference
Structural differences between the ready and unready oxidized states of [NiFe] hydrogenases., Volbeda A, Martin L, Cavazza C, Matho M, Faber BW, Roseboom W, Albracht SP, Garcin E, Rousset M, Fontecilla-Camps JC, J Biol Inorg Chem. 2005 May;10(3):239-49. Epub 2005 Apr 1. PMID:15803334 Page seeded by OCA on Sat May 3 16:40:11 2008
