Characterization of GTPase Activity of TrmE, a Member of a Novel GTPase Superfamily, from Thermotoga maritima

AUTOR(ES)
FONTE

American Society for Microbiology

RESUMO

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. Km and kcat at 70°C were 833 μM 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.

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