title: Immunological homology between the membrane-bound uptake hydrogenases of Rhizobium japonicum and Escherichia coli.
abstract: Two polypeptides present in aerobic and anaerobic cultures of Escherichia coli HB101 were shown to cross-react with antibodies to the 30- and 60-kilodalton (kDa) subunits of the uptake hydrogenase of Rhizobium japonicum. The cross-reactive polypeptides in a series of different E. coli strains are of Mrs ca. 60,000 and 30,000, and both polypeptides are present in proportion to measurable hydrogen uptake (Hup) activity (r = 0.95). The 60-kDa polypeptide from E. coli HB101 comigrated on native gels with detectable Hup activity. The exact role of the 30-kDa polypeptide in E. coli is unclear. E. coli MBM7061, a natural Hup- variant, grown anaerobically or aerobically lacked detectable Hup activity and failed to cross-react with the antisera against the hydrogenase from R. japonicum. Anaerobically cultured E. coli MBM7061, however, did express formate hydrogenlyase activity, indicating that the hydrogenases involved in the oxygen-dependent activation of hydrogen and the formate-dependent evolution of hydrogen are biochemically distinct.
mesh_terms: D000332:Aerobiosis; D000693:Anaerobiosis; D001426:Bacterial Proteins / Q000235:genetics; D001692:Biological Transport; D003429:Cross Reactions; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics / Q000276:immunology*; D005798:Genes, Bacterial; D006859:Hydrogen / Q000378:metabolism; D006864:Hydrogenase / Q000235:genetics / Q000276:immunology*; D008970:Molecular Weight; D009693:Nucleic Acid Hybridization; D010084:Oxidation-Reduction; D012231:Rhizobium / Q000235:genetics / Q000276:immunology*; D012689:Sequence Homology, Nucleic Acid
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D006859:Hydrogen; D006864:Hydrogenase