Crystal Structures of Xanthomonas Small Heat Shock Protein Provide a Structural Basis for an Active Molecular Chaperone Oligomer

dc.contributorUniversidade Estadual Paulista (UNESP)
dc.creatorHilario, Eduardo
dc.creatorMedrano Martin, Francisco Javier
dc.creatorBertolini, Maria Celia
dc.creatorFan, Li
dc.date2014-05-20T14:17:54Z
dc.date2016-10-25T17:40:13Z
dc.date2014-05-20T14:17:54Z
dc.date2016-10-25T17:40:13Z
dc.date2011-04-22
dc.date.accessioned2017-04-05T22:26:18Z
dc.date.available2017-04-05T22:26:18Z
dc.identifierJournal of Molecular Biology. London: Academic Press Ltd- Elsevier B.V. Ltd, v. 408, n. 1, p. 74-86, 2011.
dc.identifier0022-2836
dc.identifierhttp://hdl.handle.net/11449/25360
dc.identifierhttp://acervodigital.unesp.br/handle/11449/25360
dc.identifier10.1016/j.jmb.2011.02.004
dc.identifierWOS:000289813700007
dc.identifierWOS000289813700007.pdf
dc.identifierhttp://dx.doi.org/10.1016/j.jmb.2011.02.004
dc.identifier.urihttp://repositorioslatinoamericanos.uchile.cl/handle/2250/870259
dc.descriptionSmall heat shock proteins (sHsps) are ubiquitous low-molecular-weight chaperones that prevent protein aggregation under cellular stresses. sHsps contain a structurally conserved alpha-crystallin domain (ACD) of about 100 amino acid residues flanked by varied N- and C-terminal extensions and usually exist as oligomers. Oligomerization is important for the biological functions of most sHsps. However, the active oligomeric states of sHsps are not defined yet. We present here crystal structures (up to 1.65 angstrom resolution) of the sHspA from the plant pathogen Xanthomonas (XaHspA). XaHspA forms closed or open trimers of dimers (hexamers) in crystals but exists predominantly as 36mers in solution as estimated by size-exclusion chromatography. The XaHspA monomer structures mainly consist of alpha-crystallin domain with disordered N- and C-terminal extensions, indicating that the extensions are flexible and not essential for the formation of dimers and 36mers. Under reducing conditions where a-lactalbumin (LA) unfolds and aggregates, XaHspA 36mers formed complexes with one LA per XaHspA dimer. Based on XaHspA dimer dimer interactions observed in crystals, we propose that XaHspA 36mers have four possible conformations, but only XaHspA 36merB, which is formed by open hexamers in 12mer-6mer-6mer-12mer with protruding dimers accessible for substrate (unfolding protein) binding, can bind to 18 reduced LA molecules. Together, our results unravel the structural basis of an active sHsp oligomer. (C) 2011 Elsevier Ltd. All rights reserved.
dc.descriptionFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
dc.languageeng
dc.publisherAcademic Press Ltd Elsevier B.V. Ltd
dc.relationJournal of Molecular Biology
dc.rightsinfo:eu-repo/semantics/openAccess
dc.subjectalpha-crystallin domain
dc.subjectprotein folding
dc.subjectcataracts
dc.subjectcitrus canker
dc.subjectheat shock response
dc.titleCrystal Structures of Xanthomonas Small Heat Shock Protein Provide a Structural Basis for an Active Molecular Chaperone Oligomer
dc.typeOtro


Este ítem pertenece a la siguiente institución