9317273 Matthews A combination of biophysical and genetic engineering methods will be used to probe the mechanism of folding of dihydrofolate reductase from Escherichia coli. Kinetic studies of this process reveal a variety of partially-folded forms which appear in the millisecond time range and persist until the appearance of the native form many seconds or minutes later. Comparisons of the results of optical and NMR spectroscopy provide information on the development of secondary and tertiary structure in these transient species. Variations in solution conditions can provide information into the stabilities of these intermediates and, thereby, the role of thermodynamics in driving the folding to a successful conclusion. Mutational analysis pinpoints those individual amino acids which play key roles in folding and, in combination with the kinetic results, the step at which those roles are executed. Taken altogether, the information obtained by these various methods and techniques will enhance our understanding of the mechanism by which the amino acid sequence directs the rapid and efficient folding to the native, functional form. %%% One of the outstanding problems in biochemistry is the mechanism by which the amino acid sequence of a protein directs the rapid and efficient folding to the native conformation. A combination of biophysical and genetic engineering methods will be employed to probe the structures and stabilities of partially-folded forms which appear during the folding of dihydrofolate reductase. Underpinning this approach is the rationale that an understanding of these folding intermediates will serve to elucidate the complex mechanism involved. Success should enhance our fundamental knowledge of biopolymers, increase our understanding of genetic diseases, and lead to improved methods of production of protein products by the biotechnology industry. ***
