Protein folding unfolding

Taketomi H, Ueda Y and Go N 1975 Studies on protein folding, unfolding, and fluctuations by computer simulation Int. J. Pept. Protein Res. 7 445-59... 

H Taketomi, Y Ueda, N Go. Studies on protein folding, unfolding and fluctuations by computer simulation. 1. The effect of specific ammo acid sequence represented by specific mter-umt interactions. Int J Peptide Protein Res 7 445-459, 1975. 

V Daggett, M Levitt. Protein folding <-> unfolding dynamics. Cuit Opm Stiaict Biol 4 291-295, 1994. 

Beck DAC, Daggett V. Methods for molecular dynamics simulations of protein folding/unfolding in solution. Methods 2004 34 112-20. 

VJ Hilser, CD Worosila, E Freire. Analysis of thermal-induced proteins folding/ unfolding transitions using free-solution capillary electrophoresis. Anal. Biochem. 208 125-131 (1993). 

Equations (l)-(4) provide the basic statistical thermodynamic framework necessary to deal with the protein folding problem. Several years ago, Freire and Biltonen (1978a) showed that scanning calorimetry data could be used to evaluate the protein folding/unfolding partition function experimentally by a double integration procedure ... 

Fig. 4. Schematic representation of the partition function [Eq. (1)] for protein folding/unfolding. Each state, from the native state (i = 0) to the unfolded state (i = n) and all intermediates (i = 1 to n - 1), is assigned a AG relative to the native state from which the statistical weights are obtained. The partition function, Q, is simply the sum of the statistical weights of all the states. Other important parameters, including the population of each state [Eq. (2)], the excess enthalpy [Eq. (3)], and the excess heat capacity [Eq. (4)], are determined from the partition function as described in the text.

An interesting aspect of the photoreaction of PYP is the similarity to the protein folding/unfolding reaction. Hellingwerf and his coworkers applied the transition state theory to the photoreaction of PYP and estimated the thermodynamic parameters, the entropy, enthalpy, and heat capacity changes of activation [29]. They also carried out thermodynamic analysis on the thermal denaturation of PYP. Consequently, they found that the heat capacity changes in the photoreaction are comparable to those in the unfolding... 

Methods presently employed for obtaining correctly refolded proteins from inclusion body preparations are often all-or-none propositions. They typically consist of denaturant solubilization, in urea or guanidine, followed by dilution or dialysis (2). Recovery of native activity or structure may be aided by using additives (enzyme inhibitors, co-factors, oxidation-reduction couples, etc.), which act to stabilize the native-state protein conformation. However, because such efforts are time-consuming and tedious, systematic examinations of solution conditions for protein folding/unfolding are rarely performed. 

Freire E. Statistical thermodynamic analysis of (he heat capacity function associated with protein folding-unfolding transitions. Coimnents Mol Cell Biophys 1989 6(2) 123-140. 

J. Skolnick and A. Kolinski, J. Mol. Biol., 212, 787 (1990). Dynamic Monte Carlo Simulations of Globular Protein Folding/Unfolding Pathways. I. Six-Member, Greek Key Beta-Barrel Proteins. 

Qu KB, Vaughn JL, Sienkiewicz A, Scholes CP, Fetrow IS (1997) Kinetics and motional dynamics of spin-labeled yeast iso-1-cytochrome c.l. Stopped-flow electron paramagnetic resonance as a probe for protein folding/unfolding of the C-terminal helix spin-labeled at cysteine 102. Biochemistry 36 2884—2897... 

Anton, M. and D. W. Bolen. 2005. Predicting the energetics of osmolyte-induced protein folding/unfolding. Proceedings of the National Academy of Sciences of the United States of America. 102,15065. 

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