title: GTPase properties of the interferon-induced human guanylate-binding protein 2.
abstract: Guanylate-binding proteins (GBPs) were originally described as proteins that are strongly induced by interferons and are capable of binding to agarose-immobilized guanine nucleotides. hGBP1, the first of two members of this protein family in humans, was recently shown to represent a novel type of GTPase that hydrolyzes GTP predominantly to GMP. We now report that purified recombinant hGBP2 also hydrolyzes GTP very efficiently, although GDP rather than GMP was the major reaction product. The biochemical parameters of this reaction were as follows: Km = 313 microM, turnover number = 22 min-1. Both hGBP1 and hGBP2 failed to hydrolyze GDP, however, GDP was an effective inhibitor of the hGBP2- but not the hGBP1-catalyzed GTP hydrolysis reaction. Thus, hGBP1 and hGBP2 have similar biochemical properties, but show pronounced differences in product specificity.
authors.affiliation: Abteilung Virologie, Institut für Medizinische Mikrobiologie und Hygiene, Universität Freiburg, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Neun
authors.forename: M F
authors.initials: MF
authors.lastname: Richter
authors.forename: P
authors.initials: P
authors.lastname: Staeheli
authors.forename: M
authors.initials: M
authors.lastname: Schwemmle
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002460:Cell Line; D002851:Chromatography, High Pressure Liquid; D003001:Cloning, Molecular; D017931:DNA Primers; D018076:DNA, Complementary; D004926:Escherichia coli; D020558:GTP Phosphohydrolases / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
chemical_list: D017931:DNA Primers; D018076:DNA, Complementary; D012333:RNA, Messenger; D011994:Recombinant Proteins; D006160:Guanosine Triphosphate; D020558:GTP Phosphohydrolases