Kinetics and interaction studies between cytochrome c(3) and Fe-only hydrogenase from Desulfovibrio vulgaris Hildenborough

Hydrogenases from Desulfovibrio are found to catalyze hydrogen uptake with low potential multiheme cytochromes, such as cytochrome c(3), acting as acc epters. The production of Fe-only hydrogenase from Desulfovibrio vulgaris H ildenborough was improved with respect to the growth phase and media to det ermine the best large-scale bacteria growth conditions. The interaction and electron transfer from Fe-only hydrogenase to multiheme cytochrome has bee n studied in detail by both BIAcore and steady-state measurements. The elec tron transfer between [Fe] hydrogenase and cytochrome c(3) appears to be a cooperative phenomenon (h = 1.37), This behavior could be related to the co nductivity properties of multi-hemic cytochromes, An apparent dissociation constant was determined (2 x 10(-7) M), The importance of the cooperativity for contrasting models proposed to describe the functional role of the hyd rogenase/cytochrome c(3) complex is discussed. Presently, the only determin ed structure is from [NiFe] hydrogenase and there are no obvious similariti es between [NiFe] and [Fe] hydrogenase, Furthermore, no crystallographic da ta are available concerning [Fe] hydrogenase. The first results on crystall ization and X-ray crystallography are reported. (C) 1998 Wiley-Liss, Inc.