Statistical analysis folding rates

STATISTICAL ANALYSIS OF PROTEIN FOLDING KINETICS TABLE Xn Single-Input Correlations for Unfolding Rates 27... 

In this section we describe statistical analyses of measured rates of protein folding. Earlier studies are reviewed and an analysis of currently available experimental data is presented. The physical bases of the results are then discussed. 

In connecting these ideas with earlier phenomenological models, it is not obvious how to reconcile the dependence of the rate on the structure with a nucleation mechanism, as in Ref. 50. The statistical relationship suggests that the transition state contains a considerable amount of native structure, while a nucleus, in the classic sense of the word, is a small part of the structure. However, it could be that a limited number of native contacts (i.e., those in the nucleus) are sufficient to confine the transition state ensemble to a native-like fold. This idea is supported by a recent analysis of the folding transition state of acylphosphatase in which key residues, as determined by a < ) value analysis, play a critical role [56]. 

In Section VIII, we incorporated into the lattice model features expected due to the presence of a macromolecular chain running throu the structure. We have not yet performed a kinetic analysis for this model according to the above description of protein dmaturation kinetics. It is to be expected that the conformations of Fig. 12 provide a sufficient set on which to perform the search for the slowest step in the fastest sequence of steps. The problon of performing this search is by no means a trivial one and we have not yet attempted to solve it Also there remains the problem of what is the rate of folding of a looped chain with respect to that of a chain with two free ends. (That is, if one wishes to consider such conformations in spite of the fact that these have relatively low statistical weights, i.e. low Kf.)... 

The sphemlite growth rate and bulk crystallization kinetics of OBCs was studied. Rejection of the non-crystallizable soft block from the gro face decreases the crystallization kinetics of OBCs with increasing soft block content. The sphemlite growth rate conformed to the LH analysis and it was shown that a more disordered fold surface is obtained with increasing soft block content. Avrami analysis of bulk crystallization kinetics confirms sphemlitic growth and heterogeneous nucleation. It was also shown that statistical sequences crystallize much slower than ethylene blocks in OBCs. 

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