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Updated: Aug 14, 2026

Comparing the Affinity of GTPase-binding Proteins using Competition Assays
Published on: October 8, 2015
Biochemical properties of the Vibrio harveyi CgtAV GTPase
A E Sikora1, K Datta, J R Maddock
1Department of Molecular, Cellular and Developmental Biology, University of Michigan, 830 North University, Ann Arbor, MI 48109, USA.
Abstract:
Bacteria encode a number of relatively poorly characterized GTPases, including the essential, ribosome-associated Obg/CgtA proteins. In contrast to Ras-like proteins, it appears that the Obg/CgtA proteins bind guanine nucleotides with modest affinity and hydrolyze GTP relatively slowly. We show here that the Vibrio harveyi CgtA(V) exchanges guanine nucleotides rapidly and has a modest affinity for nucleotides, suggesting that these features are a universal property of the Obg/CgtA family. Interestingly, CgtA(V) possesses a significantly more rapid GTP hydrolysis rate than is typical of other family members, perhaps reflecting the diversity and specificity of bacterial ecological niches.
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