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Article: Mapping the binding site for the GTP-binding protein Rac-1 on its inhibitor RhoGDI-1

TitleMapping the binding site for the GTP-binding protein Rac-1 on its inhibitor RhoGDI-1
Authors
Issue Date2000
PublisherCell Press. The Journal's web site is located at http://www.elsevier.com/locate/str
Citation
Structure, 2000, v. 8 n. 1, p. 47-55 How to Cite?
AbstractBackground: Members of the Rho family of small GTP-binding proteins, such as Rho, Rac and Cdc42, have a role in a wide range of cell responses. These proteins function as molecular switches by virtue of a conformational change between the GTP-bound (active) and GDP-bound (inactive) forms. In addition, most members of the Rho and Rac subfamilies cycle between the cytosol and membrane. The cytosolic guanine nucleotide dissociation inhibitors, RhoGDIs, regulate both the GDP/GTP exchange cycle and the membrane association/dissociation cycle. Results: We have used NMR spectroscopy and site-directed mutagenesis to identify the regions of human RhoGDI-1 that are involved in binding Rac-1. The results emphasise the importance of the flexible regions of both proteins in the interaction. At least one specific region (residues 46-57) of the flexible N-terminal domain of RhoGDI, which has a tendency to form an amphipathic helix in the free protein, makes a major contribution to the binding energy of the complex. In addition, the primary site of Rac-1 binding on the folded domain of RhoGDI involves the β4-β5 and β6-β7 loops, with a slight movement of the 310 helix accompanying the interaction. This binding site is on the same face of the protein as the binding site for the isoprenyl group of post- translationally modified Rac-1, but is distinct from this site. Conclusions: Isoprenylated Rac-1 appears to interact with three distinct sites on RhoGDI. The isoprenyl group attached to the C terminus of Rac-1 binds in a pocket in the folded domain of RhoGDI. This is distinct from the major site on this domain occupied by Rac-1 itself, which involves two loops at the opposite end to the isoprenyl-binding site. It is probable that the flexible C-terminal region of Rac-1 extends from the site at which Rac-1 contacts the folded domain of RhoGDI to allow the isoprenyl group to bind in the pocket at the other end of the RhoGDI molecule. Finally, the flexible N terminus of RhoGDI- 1, and particularly residues 48-58, makes a specific interaction with Rac-1 which contributes substantially to the binding affinity.
Persistent Identifierhttp://hdl.handle.net/10722/157317
ISSN
2015 Impact Factor: 5.237
2015 SCImago Journal Rankings: 4.770
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorLian, LYen_US
dc.contributor.authorBarsukov, Ien_US
dc.contributor.authorGolovanov, APen_US
dc.contributor.authorHawkins, DIen_US
dc.contributor.authorBadii, Ren_US
dc.contributor.authorSze, KHen_US
dc.contributor.authorKeep, NHen_US
dc.contributor.authorBokoch, GMen_US
dc.contributor.authorRoberts, GCKen_US
dc.date.accessioned2012-08-08T08:48:52Z-
dc.date.available2012-08-08T08:48:52Z-
dc.date.issued2000en_US
dc.identifier.citationStructure, 2000, v. 8 n. 1, p. 47-55en_US
dc.identifier.issn0969-2126en_US
dc.identifier.urihttp://hdl.handle.net/10722/157317-
dc.description.abstractBackground: Members of the Rho family of small GTP-binding proteins, such as Rho, Rac and Cdc42, have a role in a wide range of cell responses. These proteins function as molecular switches by virtue of a conformational change between the GTP-bound (active) and GDP-bound (inactive) forms. In addition, most members of the Rho and Rac subfamilies cycle between the cytosol and membrane. The cytosolic guanine nucleotide dissociation inhibitors, RhoGDIs, regulate both the GDP/GTP exchange cycle and the membrane association/dissociation cycle. Results: We have used NMR spectroscopy and site-directed mutagenesis to identify the regions of human RhoGDI-1 that are involved in binding Rac-1. The results emphasise the importance of the flexible regions of both proteins in the interaction. At least one specific region (residues 46-57) of the flexible N-terminal domain of RhoGDI, which has a tendency to form an amphipathic helix in the free protein, makes a major contribution to the binding energy of the complex. In addition, the primary site of Rac-1 binding on the folded domain of RhoGDI involves the β4-β5 and β6-β7 loops, with a slight movement of the 310 helix accompanying the interaction. This binding site is on the same face of the protein as the binding site for the isoprenyl group of post- translationally modified Rac-1, but is distinct from this site. Conclusions: Isoprenylated Rac-1 appears to interact with three distinct sites on RhoGDI. The isoprenyl group attached to the C terminus of Rac-1 binds in a pocket in the folded domain of RhoGDI. This is distinct from the major site on this domain occupied by Rac-1 itself, which involves two loops at the opposite end to the isoprenyl-binding site. It is probable that the flexible C-terminal region of Rac-1 extends from the site at which Rac-1 contacts the folded domain of RhoGDI to allow the isoprenyl group to bind in the pocket at the other end of the RhoGDI molecule. Finally, the flexible N terminus of RhoGDI- 1, and particularly residues 48-58, makes a specific interaction with Rac-1 which contributes substantially to the binding affinity.en_US
dc.languageengen_US
dc.publisherCell Press. The Journal's web site is located at http://www.elsevier.com/locate/stren_US
dc.relation.ispartofStructureen_US
dc.subject.meshAmino Acid Sequenceen_US
dc.subject.meshAnimalsen_US
dc.subject.meshBinding Sites - Geneticsen_US
dc.subject.meshGuanine Nucleotide Dissociation Inhibitors - Chemistry - Genetics - Metabolismen_US
dc.subject.meshHumansen_US
dc.subject.meshMagnetic Resonance Spectroscopyen_US
dc.subject.meshModels, Molecularen_US
dc.subject.meshMolecular Sequence Dataen_US
dc.subject.meshMutagenesis, Site-Directeden_US
dc.subject.meshProtein Bindingen_US
dc.subject.meshProtein Conformationen_US
dc.subject.meshProtein Foldingen_US
dc.subject.meshProtein Structure, Tertiaryen_US
dc.subject.meshRecombinant Proteins - Chemistry - Genetics - Metabolismen_US
dc.subject.meshSequence Homology, Amino Aciden_US
dc.subject.meshThermodynamicsen_US
dc.subject.meshRac1 Gtp-Binding Protein - Antagonists & Inhibitors - Metabolismen_US
dc.titleMapping the binding site for the GTP-binding protein Rac-1 on its inhibitor RhoGDI-1en_US
dc.typeArticleen_US
dc.identifier.emailSze, KH:khsze@hku.hken_US
dc.identifier.authoritySze, KH=rp00785en_US
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.doi10.1016/S0969-2126(00)00080-0en_US
dc.identifier.pmid10673424-
dc.identifier.scopuseid_2-s2.0-0034650210en_US
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-0034650210&selection=ref&src=s&origin=recordpageen_US
dc.identifier.volume8en_US
dc.identifier.issue1en_US
dc.identifier.spage47en_US
dc.identifier.epage55en_US
dc.identifier.isiWOS:000084873000006-
dc.publisher.placeUnited Statesen_US
dc.identifier.scopusauthoridLian, LY=7005156195en_US
dc.identifier.scopusauthoridBarsukov, I=35586964900en_US
dc.identifier.scopusauthoridGolovanov, AP=7005101415en_US
dc.identifier.scopusauthoridHawkins, DI=15720956300en_US
dc.identifier.scopusauthoridBadii, R=6603978077en_US
dc.identifier.scopusauthoridSze, KH=7006735061en_US
dc.identifier.scopusauthoridKeep, NH=7003604750en_US
dc.identifier.scopusauthoridBokoch, GM=7102089474en_US
dc.identifier.scopusauthoridRoberts, GCK=7403400348en_US

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