Distinct Unfolding and Refolding Pathways of Ribonuclease A Revealed by Heating and Cooling Temperature Jumps
dc.contributor.author
dc.date.accessioned
2011-09-14T15:52:57Z
dc.date.available
2011-09-14T15:52:57Z
dc.date.issued
2008
dc.identifier.citation
Torrent ,J., Marchal, S., Ribó, M., Vilanova, M., Georges, C., Dupont, Y., i Lange, R. (2008). Distinct unfolding and refolding pathways of ribonuclease a revealed by heating and cooling temperature jumps. Biophysical Journal, 94 (10), 4056-4065. Recuperat 14 setembre de 2011, a doi:10.1529/biophysj.107.123893
dc.identifier.issn
0006-3495
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dc.description.abstract
Heating and cooling temperature jumps (T-jumps) were performed using a newly developed technique to trigger unfolding and refolding of wild-type ribonuclease A and a tryptophan-containing variant (Y115W). From the linear Arrhenius plots of the microscopic folding and unfolding rate constants, activation enthalpy (ΔH#), and activation entropy (ΔS#) were determined to characterize the kinetic transition states (TS) for the unfolding and refolding reactions. The single TS of the wild-type protein was split into three for the Y115W variant. Two of these transition states, TS1 and TS2, characterize a slow kinetic phase, and one, TS3, a fast phase. Heating T-jumps induced protein unfolding via TS2 and TS3; cooling T-jumps induced refolding via TS1 and TS3. The observed speed of the fast phase increased at lower temperature, due to a strongly negative ΔH# of the folding-rate constant. The results are consistent with a path-dependent protein folding/unfolding mechanism. TS1 and TS2 are likely to reflect X-Pro114 isomerization in the folded and unfolded protein, respectively, and TS3 the local conformational change of the β-hairpin comprising Trp115. A very fast protein folding/unfolding phase appears to precede both processes. The path dependence of the observed kinetics is suggestive of a rugged energy protein folding funne
dc.description.sponsorship
This work was carried out in the frame of COST Chemistry D30-WG005 cooperation and supported by a grant (BFU2006-15543-CO2-02/BMC) from the Ministerio de Educacio´n y Ciencia (Spain)
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application/pdf
dc.language.iso
eng
dc.publisher
Biophysical Society
dc.relation
MEC/PN 2006-2009/BFU2006-15543-CO2-02
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Reproducció digital del document publicat a: http://dx.doi.org/10.1529/biophysj.107.123893
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© Biophysical Journal, 2008, vol. 94, núm. 10, p.4056-4065
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Articles publicats (D-B)
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Tots els drets reservats
dc.subject
dc.title
Distinct Unfolding and Refolding Pathways of Ribonuclease A Revealed by Heating and Cooling Temperature Jumps
dc.type
info:eu-repo/semantics/article
dc.rights.accessRights
info:eu-repo/semantics/openAccess
dc.type.version
info:eu-repo/semantics/publishedVersion
dc.identifier.doi
dc.identifier.idgrec
009776
dc.contributor.funder