title: HupUV proteins of Rhodobacter capsulatus can bind H2: evidence from the H-D exchange reaction.
abstract: The H-D exchange reaction has been measured with the D2-H2O system, for Rhodobacter capsulatus JP91, which lacks the hupSL-encoded hydrogenase, and R. capsulatus BSE16, which lacks the HupUV proteins. The hupUV gene products, expressed from plasmid pAC206, are shown to catalyze an H-D exchange reaction distinguishable from the H-D exchange due to the membrane-bound, hupSL-encoded hydrogenase. In the presence of O2, the uptake hydrogenase of BSE16 cells catalyzed a rapid uptake and oxidation of H2, D2, and HD present in the system, and its activity (H-D exchange, H2 evolution in presence of reduced methyl viologen [MV+]) depended on the external pH, while the H-D exchange due to HupUV remained insensitive to external pH and O2. These data suggest that the HupSL dimer is periplasmically oriented, while the HupUV proteins are in the cytoplasmic compartment.
authors.affiliation: CEA/Grenoble, Laboratoire de Biochimie Microbienne (Centre National de la Recherche Scientifique Unité de Recherche Associée no. 1130)/Département de Biologie Moléculaire et Structurale, France. pmv@miage.ceng.cea.fr
authors.forename: P M
authors.initials: PM
authors.lastname: Vignais
authors.forename: B
authors.initials: B
authors.lastname: Dimon
authors.forename: N A
authors.initials: NA
authors.lastname: Zorin
authors.forename: A
authors.initials: A
authors.lastname: Colbeau
authors.forename: S
authors.initials: S
authors.lastname: Elsen
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport; D003903:Deuterium / Q000378:metabolism; D017666:Deuterium Oxide; D006859:Hydrogen / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D006864:Hydrogenase / Q000378:metabolism; D009154:Mutation; D010088:Oxidoreductases; D011485:Protein Binding; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D016354:Rhodobacter capsulatus / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; C101649:HupU protein, Rhodobacter capsulatus; C101650:HupV protein, Rhodobacter capsulatus; D012097:Repressor Proteins; D006859:Hydrogen; D003903:Deuterium; D010088:Oxidoreductases; C091789:HupL protein, Anabaena; D006864:Hydrogenase; D017666:Deuterium Oxide