GTP Binding is Necessary for the Activation of a Toxic Mutant Isoform of the Essential GTPase ObgE.

TitleGTP Binding is Necessary for the Activation of a Toxic Mutant Isoform of the Essential GTPase ObgE.
Publication TypeJournal Article
Year of Publication2019
AuthorsDewachter, L., B. Deckers, E. Martin, P. Herpels, S. Gkekas, W. Versées, N. Verstraeten, M. Fauvart, and J. Michiels
JournalInt J Mol Sci
Date Published2019 Dec 18

Even though the Obg protein is essential for bacterial viability, the cellular functions of this universally conserved GTPase remain enigmatic. Moreover, the influence of GTP and GDP binding on the activity of this protein is largely unknown. Previously, we identified a mutant isoform of ObgE (the Obg protein of ) that triggers cell death. In this research we explore the biochemical requirements for the toxic effect of this mutant ObgE* isoform, using cell death as a readily accessible read-out for protein activity. Both the absence of the N-terminal domain and a decreased GTP binding affinity neutralize ObgE*-mediated toxicity. Moreover, a deletion in the region that connects the N-terminal domain to the G domain likewise abolishes toxicity. Taken together, these data indicate that GTP binding by ObgE* triggers a conformational change that is transmitted to the N-terminal domain to confer toxicity. We therefore conclude that ObgE*-GTP, but not ObgE*-GDP, is the active form of ObgE* that is detrimental to cell viability. Based on these data, we speculate that also for wild-type ObgE, GTP binding triggers conformational changes that affect the N-terminal domain and thereby control ObgE function.

Alternate JournalInt J Mol Sci
PubMed ID31861427
PubMed Central IDPMC6982127
Grant ListG047122N, G0B2515N and G055517N / / Fonds Wetenschappelijk Onderzoek /
SRP34 / / Vrije Universiteit Brussel /
P7/28 / / Belgian Federal Science Policy Office /
C16/17/006 / / KU Leuven /
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