The product of the hypB gene, which is required for nickel incorporation into hydrogenases, is a novel guanine nucleotide-binding protein.

摘要: The products of the hyp operon genes are essential for formation catalytically active hydrogenases in Escherichia coli. At least one these auxiliary proteins, HYPB, appears to be involved nickel liganding hydrogenase apoprotein, since mutations hypB can phenotypically suppressed by high concentrations medium (R. Waugh and D. H. Boxer, Biochimie 68:157-166, 1986). To approach identification specific function we overexpressed gene purified characterized product. HYPB is a homodimer 31.6-kDa subunits, it binds guanine nucleotides, with Kd GDP 1.2 microM. protein displays low level GTPase activity, kcat 0.17 min-1. apparent Km GTP, as measured GTP hydrolysis reaction, was determined 4 A chromatography system established measure insertion into 3 from E. coli determine effects lesions hypB. Nickel associated only processed large subunit wild type, mutants accumulate precursor form this subunit, which devoid nickel. results discussed terms model donation apoprotein thought reverse interaction between either or another nickel-binding after has been released.