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Please use this identifier to cite or link to this item: http://hdl.handle.net/10481/31078

Title: Highly Anomalous Energetics of Protein Cold Denaturation Linked to Folding-Unfolding Kinetics
Authors: Romero Romero, María Luisa
Inglés Prieto, Álvaro
Ibarra Molero, Beatriz
Sánchez Ruiz, José Manuel
Issue Date: 2011
Abstract: Despite several careful experimental analyses, it is not yet clear whether protein cold-denaturation is just a “mirror image” of heat denaturation or whether it shows unique structural and energetic features. Here we report that, for a well-characterized small protein, heat denaturation and cold denaturation show dramatically different experimental energetic patterns. Specifically, while heat denaturation is endothermic, the cold transition (studied in the folding direction) occurs with negligible heat effect, in a manner seemingly akin to a gradual, second-order-like transition. We show that this highly anomalous energetics is actually an apparent effect associated to a large folding/unfolding free energy barrier and that it ultimately reflects kinetic stability, a naturally-selected trait in many protein systems. Kinetics thus emerges as an important factor linked to differential features of cold denaturation. We speculate that kinetic stabilization against cold denaturation may play a role in cold adaptation of psychrophilic organisms. Furthermore, we suggest that folding-unfolding kinetics should be taken into account when analyzing in vitro cold-denaturation experiments, in particular those carried out in the absence of destabilizing conditions.
Sponsorship: This work was supported by FEDER (“Fondo Europeo de DEsarrollo Regional”) funds and Grants BIO2009-09562 and CSD2009-00088 from the Spanish Ministry of Science and Innovation.
Publisher: Public Library of Science (PLOS)
Keywords: Calorimetry
Chlorides
Circular dichroism spectroscopy
Energetic materials
Enthalpy
Free energy
Guanidines
Relaxation (physics)
URI: http://hdl.handle.net/10481/31078
ISSN: 1932-6203
Rights : Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License
Citation: Romero Romero, M.L.; Inglés Prieto, A.; Ibarra Molero, B.; Sánchez Ruiz, J.M. Highly Anomalous Energetics of Protein Cold Denaturation Linked to Folding-Unfolding Kinetics. Plos One, 6(7): e23050 (2011). [http://hdl.handle.net/10481/31078]
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