| We extend the WSME model, to include the phenomenological information coming from Freire's results on the different contributions to proteins specific heat. We adjust the four parameters of the resulting model by fitting the raw calorimetric data for gpW and SH3 domain, without baseline subtraction, to avoid the known problems relative to baseline identification for weakly cooperative proteins. We use the resulting model to describe both the thermodynamics (through exact solution) and the kinetics (with MC simulations) of the proteins, with a special attention to gpW, and we are able to reproduce several of the experimental features, both for thermodynamics and kinetics. Our results show that, despite the similar size and mid-folding temperature, the two proteins show very different behaviors: while the SH3 domain appears as a clear two-state protein, gpW shows a free-energy landscape with small barriers (around 5 kJ/mol), and a kinetics which presents a slow phase, corresponding to folding, and a fast phase, of re-arrangements within the initial basin. |
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