title: Characterization of GTPase activity of TrmE, a member of a novel GTPase superfamily, from Thermotoga maritima.
abstract: A gene encoding a putative GTP-binding protein, a TrmE homologue that is highly conserved in both prokaryotes and eukaryotes, was cloned from Thermotoga maritima, a hyperthermophilic bacterium. T. maritima TrmE was overexpressed in Escherichia coli and purified. TrmE has a GTPase activity but no ATPase activity. The GTPase activity can be competed with GTP, GDP, and dGTP but not with GMP, ATP, CTP, or UTP. K(m) and k(cat) at 70 degrees C were 833 microM and 9.3 min(-1), respectively. Our results indicate that TrmE is a GTP-binding protein with a very high intrinsic GTP hydrolysis rate. We also propose that TrmE homologues constitute a novel subfamily of the GTPase superfamily.
authors.affiliation: Department of Biochemistry, Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA.
authors.forename: K
authors.initials: K
authors.lastname: Yamanaka
authors.forename: J
authors.initials: J
authors.lastname: Hwang
authors.forename: M
authors.initials: M
authors.lastname: Inouye
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins; D003001:Cloning, Molecular; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D008969:Molecular Sequence Data; D020124:Thermotoga maritima / Q000201:enzymology* / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; C417279:TRME protein, Thermotoga maritima; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins