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Article: The Caulobacter crescentus CgtA protein displays unusual guanine nucleotide binding and exchange properties

TitleThe Caulobacter crescentus CgtA protein displays unusual guanine nucleotide binding and exchange properties
Authors
KeywordsSpecies Index: Bacteria (Microorganisms)
Caulobacter Vibrioides
Eukaryota
Negibacteria
Issue Date1999
PublisherAmerican Society for Microbiology
Citation
Journal of Bacteriology, 1999, v. 181 n. 18, p. 5825-5832 How to Cite?
AbstractThe Caulobacter crescentus CgtA protein is a member of the Obg-GTP1 subfamily of monomeric GTP-binding proteins. In vitro, CgtA specifically bound GTP and GDP but not GMP or ATP. CgtA bound GTP and GDP with moderate affinity at 30°C and displayed equilibrium binding constants of 1.2 and 0.5 μM, respectively, in the presence of Mg2+. In the absence of Mg2+, the affinity of CgtA for GTP and GDP was reduced 59- and 6-fold, respectively. N- Methyl-3'-O-anthranoyl (mant)-guanine nucleotide analogs were used to quantify GDP and GTP exchange. Spontaneous dissociation of both GDP and GTP in the presence of 5 to 12 mM Mg2+ was extremely rapid (k(d) = 1.4 and 1.5 s-1, respectively), 103- to 105-fold faster than that of the well- characterized eukaryotic Ras-like GTP-binding proteins. The dissociation rate constant of GDP increased sevenfold in the absence of Mg2+. Finally, there was a low inherent GTPase activity with a single-turnover rate constant of 5.0 x 10-4 S-1 corresponding to a half-life of hydrolysis of 23 min. These data clearly demonstrate that the guanine nucleotide binding and exchange properties of CgtA are different from those of the well- characterized Ras-like GTP-binding proteins. Furthermore, these data are consistent with a model whereby the nucleotide occupancy of CgtA is controlled by the intracellular levels of guanine nucleotides.
Persistent Identifierhttp://hdl.handle.net/10722/90933
ISSN
2015 Impact Factor: 3.198
2015 SCImago Journal Rankings: 2.216
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorLin, Ben_HK
dc.contributor.authorCovalle, KLen_HK
dc.contributor.authorMaddock, JRen_HK
dc.date.accessioned2010-09-17T10:10:33Z-
dc.date.available2010-09-17T10:10:33Z-
dc.date.issued1999en_HK
dc.identifier.citationJournal of Bacteriology, 1999, v. 181 n. 18, p. 5825-5832en_HK
dc.identifier.issn0021-9193en_HK
dc.identifier.urihttp://hdl.handle.net/10722/90933-
dc.description.abstractThe Caulobacter crescentus CgtA protein is a member of the Obg-GTP1 subfamily of monomeric GTP-binding proteins. In vitro, CgtA specifically bound GTP and GDP but not GMP or ATP. CgtA bound GTP and GDP with moderate affinity at 30°C and displayed equilibrium binding constants of 1.2 and 0.5 μM, respectively, in the presence of Mg2+. In the absence of Mg2+, the affinity of CgtA for GTP and GDP was reduced 59- and 6-fold, respectively. N- Methyl-3'-O-anthranoyl (mant)-guanine nucleotide analogs were used to quantify GDP and GTP exchange. Spontaneous dissociation of both GDP and GTP in the presence of 5 to 12 mM Mg2+ was extremely rapid (k(d) = 1.4 and 1.5 s-1, respectively), 103- to 105-fold faster than that of the well- characterized eukaryotic Ras-like GTP-binding proteins. The dissociation rate constant of GDP increased sevenfold in the absence of Mg2+. Finally, there was a low inherent GTPase activity with a single-turnover rate constant of 5.0 x 10-4 S-1 corresponding to a half-life of hydrolysis of 23 min. These data clearly demonstrate that the guanine nucleotide binding and exchange properties of CgtA are different from those of the well- characterized Ras-like GTP-binding proteins. Furthermore, these data are consistent with a model whereby the nucleotide occupancy of CgtA is controlled by the intracellular levels of guanine nucleotides.en_HK
dc.languageengen_HK
dc.publisherAmerican Society for Microbiologyen_HK
dc.relation.ispartofJournal of Bacteriologyen_HK
dc.subjectSpecies Index: Bacteria (Microorganisms)en_HK
dc.subjectCaulobacter Vibrioidesen_HK
dc.subjectEukaryotaen_HK
dc.subjectNegibacteriaen_HK
dc.titleThe Caulobacter crescentus CgtA protein displays unusual guanine nucleotide binding and exchange propertiesen_HK
dc.typeArticleen_HK
dc.identifier.emailLin, B:blin@hku.hken_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.pmid10482526-
dc.identifier.scopuseid_2-s2.0-0032861460en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-0032861460&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume181en_HK
dc.identifier.issue18en_HK
dc.identifier.spage5825en_HK
dc.identifier.epage5832en_HK
dc.identifier.isiWOS:000082534700035-

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