2.50
Hdl Handle:
http://hdl.handle.net/10033/22972
Title:
Structure of the Yersinia enterocolitica type III secretion translocator chaperone SycD.
Authors:
Büttner, Carina R; Sorg, Isabel; Cornelis, Guy R; Heinz, Dirk W; Niemann, Hartmut H
Abstract:
Many Gram-negative bacteria use a type III secretion (T3S) system to directly inject effector molecules into eucaryotic cells in order to establish a symbiotic or pathogenic relationship with their host. The translocation of many T3S proteins requires specialized chaperones from the bacterial cytosol. SycD belongs to a class of T3S chaperones that assists the secretion of pore-forming translocators and, specifically chaperones the translocators YopB and YopD from enteropathogenic Yersinia enterocolitica. In addition, SycD is involved in the regulation of virulence factor biosynthesis and secretion. In this study, we present two crystal structures of Y. enterocolitica SycD at 1.95 and 2.6 A resolution, the first experimental structures of a T3S class II chaperone specific for translocators. The fold of SycD is entirely alpha-helical and reveals three tetratricopeptide repeat-like motifs that had been predicted from amino acid sequence. In both structures, SycD forms dimers utilizing residues from the first tetratricopeptide repeat motif. Using site-directed mutagenesis and size exclusion chromatography, we verified that SycD forms head-to-head homodimers in solution. Although in both structures, dimerization largely depends on the same residues, the two assemblies represent alternative dimers that exhibit different monomer orientations and overall shape. In these two distinct head-to-head dimers, both the concave and the convex surface of each monomer are accessible for interactions with the SycD binding partners YopB and YopD. A SycD variant carrying two point mutations in the dimerization interface is properly folded but defective in dimerization. Expression of this stable SycD monomer in Yersinia does not rescue the phenotype of a sycD null mutant, suggesting a physiological relevance of the dimerization interface.
Affiliation:
Division of Structural Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, D-38124 Braunschweig, Germany.
Citation:
Structure of the Yersinia enterocolitica type III secretion translocator chaperone SycD. 2008, 375 (4):997-1012 J. Mol. Biol.
Journal:
Journal of molecular biology
Issue Date:
25-Jan-2008
URI:
http://hdl.handle.net/10033/22972
DOI:
10.1016/j.jmb.2007.11.009
PubMed ID:
18054956
Type:
Article
Language:
en
ISSN:
1089-8638
Appears in Collections:
Publications from Division of Molekulare Struktur Biologie (MOSB)

Full metadata record

DC FieldValue Language
dc.contributor.authorBüttner, Carina R-
dc.contributor.authorSorg, Isabel-
dc.contributor.authorCornelis, Guy R-
dc.contributor.authorHeinz, Dirk W-
dc.contributor.authorNiemann, Hartmut H-
dc.date.accessioned2008-04-11T08:00:00Z-
dc.date.available2008-04-11T08:00:00Z-
dc.date.issued2008-01-25-
dc.identifier.citationStructure of the Yersinia enterocolitica type III secretion translocator chaperone SycD. 2008, 375 (4):997-1012 J. Mol. Biol.en
dc.identifier.issn1089-8638-
dc.identifier.pmid18054956-
dc.identifier.doi10.1016/j.jmb.2007.11.009-
dc.identifier.urihttp://hdl.handle.net/10033/22972-
dc.description.abstractMany Gram-negative bacteria use a type III secretion (T3S) system to directly inject effector molecules into eucaryotic cells in order to establish a symbiotic or pathogenic relationship with their host. The translocation of many T3S proteins requires specialized chaperones from the bacterial cytosol. SycD belongs to a class of T3S chaperones that assists the secretion of pore-forming translocators and, specifically chaperones the translocators YopB and YopD from enteropathogenic Yersinia enterocolitica. In addition, SycD is involved in the regulation of virulence factor biosynthesis and secretion. In this study, we present two crystal structures of Y. enterocolitica SycD at 1.95 and 2.6 A resolution, the first experimental structures of a T3S class II chaperone specific for translocators. The fold of SycD is entirely alpha-helical and reveals three tetratricopeptide repeat-like motifs that had been predicted from amino acid sequence. In both structures, SycD forms dimers utilizing residues from the first tetratricopeptide repeat motif. Using site-directed mutagenesis and size exclusion chromatography, we verified that SycD forms head-to-head homodimers in solution. Although in both structures, dimerization largely depends on the same residues, the two assemblies represent alternative dimers that exhibit different monomer orientations and overall shape. In these two distinct head-to-head dimers, both the concave and the convex surface of each monomer are accessible for interactions with the SycD binding partners YopB and YopD. A SycD variant carrying two point mutations in the dimerization interface is properly folded but defective in dimerization. Expression of this stable SycD monomer in Yersinia does not rescue the phenotype of a sycD null mutant, suggesting a physiological relevance of the dimerization interface.en
dc.language.isoenen
dc.subject.meshAmino Acid Motifsen
dc.subject.meshAmino Acid Sequenceen
dc.subject.meshBacterial Proteinsen
dc.subject.meshBiological Transporten
dc.subject.meshCrystallography, X-Rayen
dc.subject.meshDimerizationen
dc.subject.meshHydrogen Bondingen
dc.subject.meshHydrolysisen
dc.subject.meshHydrophobicityen
dc.subject.meshModels, Molecularen
dc.subject.meshMolecular Chaperonesen
dc.subject.meshMolecular Sequence Dataen
dc.subject.meshMolecular Weighten
dc.subject.meshPoint Mutationen
dc.subject.meshProtein Structure, Quaternaryen
dc.subject.meshProtein Structure, Secondaryen
dc.subject.meshSequence Homology, Amino Aciden
dc.subject.meshTrypsinen
dc.subject.meshVirulence Factorsen
dc.subject.meshX-Ray Diffractionen
dc.subject.meshYersinia enterocoliticaen
dc.titleStructure of the Yersinia enterocolitica type III secretion translocator chaperone SycD.en
dc.typeArticleen
dc.contributor.departmentDivision of Structural Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, D-38124 Braunschweig, Germany.en
dc.identifier.journalJournal of molecular biologyen

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