ISSN:
0006-3525
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Hydrogen exchange kinetics of proteins provide information about the dynamics of their structure. The interpretation of experiments has been limited by difficulty in identifying individual rate constants. In order to invert the kinetic data, and to gain information about the individual reacting sites, we introduce a Laplace inversion technique and obtain the distribution function of rate constants by which the intricate reaction proceeds. A series of carefully overlapped experiments were performed on lysozyme at 25°C, an exchange profile obtained, and a distribution function extracted. This function was composed of a product of two terms, indicating two parallel pathways. The first, a power-law term, was attributed to exchange from the native state. This part of the distribution function thus describes the scope of the conformational fluctuations in proteins at constant temperature and pressure. The second, an exponential, was seen to be associated with the pathway involving thermal unfolding and subsequent free exchange with the solvent. The influence of trichlorethanol and glycerol on the total distribution function was measured. Trichloroethanol selectively increased the contribution from the thermal unfolding pathway, whereas glycerol, besides decreasing this type of contribution, increased the width of the distribution function attributed to structural fluctuations.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bip.1980.360190509
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