The N-terminal domain of the Caulobacter crescentus CgtA protein does not function as a guanine nucleotide exchange factor.
The Caulobacter crescentus GTP binding protein CgtA is a member of the Obg/GTP1 subfamily of monomeric GTP binding proteins. In vitro, CgtA displays moderate affinity for both GDP and GTP, and rapid exchange rate constants for either nucleotide. One possible explanation for the observed rapid guanine nucleotide exchange rates is that CgtA is a bimodal protein with a C-terminal GTP binding domain and an N-terminal guanine nucleotide exchange factor (GEF) domain. In this study we demonstrate that although the N-terminus of CgtA is required for function in vivo, this domain plays no significant role in the guanine nucleotide binding, exchange or GTPase activity.
Department of Biology, University of Michigan, 830 N University, Ann Arbor, MI 48109-1048, USA.
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Lin
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JR
Maddock
D000483:Alleles; D001426:Bacterial Proteins; D016935:Caulobacter crescentus / Q000235:genetics / Q000378:metabolism*; D020558:GTP Phosphohydrolases / Q000378:metabolism; D020662:Guanine Nucleotide Exchange Factors / Q000737:chemistry / Q000378:metabolism*; D006150:Guanine Nucleotides / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism; D006868:Hydrolysis; D020559:Monomeric GTP-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary
D001426:Bacterial Proteins; D020662:Guanine Nucleotide Exchange Factors; D006150:Guanine Nucleotides; D006160:Guanosine Triphosphate; C108621:CgtA protein, bacteria; D020558:GTP Phosphohydrolases; D020559:Monomeric GTP-Binding Proteins