Comparison of chemical and thermal protein denaturation by combination of computational and experimental approaches. II
2011 (English)In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 135, no 17, 175102- p.Article in journal (Refereed) Published
Chemical and thermal denaturation methods have been widely used to investigate folding processes of proteins in vitro. However, a molecular understanding of the relationship between these two perturbation methods is lacking. Here, we combined computational and experimental approaches to investigate denaturing effects on three structurally different proteins. We derived a linear relationship between thermal denaturation at temperature T(b) and chemical denaturation at another temperature T(u) using the stability change of a protein (Delta G). For this, we related the dependence of Delta G on temperature, in the Gibbs-Helmholtz equation, to that of Delta G on urea concentration in the linear extrapolation method, assuming that there is a temperature pair from the urea (T(u)) and the aqueous (T(b)) ensembles that produces the same protein structures. We tested this relationship on apoazurin, cytochrome c, and apoflavodoxin using coarse-grained molecular simulations. We found a linear correlation between the temperature for a particular structural ensemble in the absence of urea, T(b), and the temperature of the same structural ensemble at a specific urea concentration, T(u). The in silico results agreed with in vitro far-UV circular dichroism data on apoazurin and cytochrome c. We conclude that chemical and thermal unfolding processes correlate in terms of thermodynamics and structural ensembles at most conditions; however, deviations were found at high concentrations of denaturant.
(C) 2011 American Institute of Physics. [doi: 10.1063/1.3656692]
Place, publisher, year, edition, pages
Lancaster, Pa.: American Institute of Physics (AIP), 2011. Vol. 135, no 17, 175102- p.
biochemistry, biological techniques, biothermics, circular dichroism, molecular biophysics, molecular configurations, proteins, reaction kinetics theory
IdentifiersURN: urn:nbn:se:umu:diva-50521DOI: 10.1063/1.3656692ISI: 000296733300040OAI: oai:DiVA.org:umu-50521DiVA: diva2:464979