Open AccessHupUV proteins of Rhodobacter capsulatus can bind H2: evidence from the H-D exchange reaction
Author(s) -
Paulette M. Vignais,
Bernard Dimon,
Nikolaï A. Zorin,
Annette Colbeau,
Sylvie Elsen
Publication year - 1997
Publication title -
journal of bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.652
H-Index - 246
eISSN - 1067-8832
pISSN - 0021-9193
DOI - 10.1128/jb.179.1.290-292.1997
Subject(s) - rhodobacter , hydrogenase , biology , dimer , rhodospirillaceae , biochemistry , plasmid , cytoplasm , rhodospirillales , catalysis , enzyme , gene , chemistry , organic chemistry , mutant
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.