9507255 Tasayco The goal of the research is to establish the principles underlying the folding of -sheets. The approach chosen is to study the structure, stability, dynamics and folding of a family of protein fragments. It is proposed to dissect E. coli thioredoxin, a well- characterized small monomeric protein with a mixed -structure, into fragments. They will be generated using tools of biochemistry, chemistry and molecular biology. These fragments will be characterized using a combination of biochemical and biophysical tools with increasing level of structural detail. Circular dichroism in the far and near UV, fluorescence, multidimensional nuclear magnetic resonance spectroscopy and computer modeling will also be used. The educational aspect of this proposal aims to complement the lectures of the standard one-semester Physical Chemistry course for Biochemistry majors using the Inverse Prediction Approach, which consists of building a physical 3D-model of a macromolecular and using it to predict its biophysical properties. %%% The ability to correlate structural changes with ahanges in the biological function holds the key to the understanding of the structure-function relationship of biological macromolecules. However, protein structures are not established at the same pace at which new amino acid sequence are generated. Thus solving the "protein folding problem," that is, predicting the three dimensional structure of a protein based solely on its primary sequence, has become an area of intense research. Much progress has been made in the understanding of the principles behind the formation of one kind of structure commonly found in proteins, the -helix. However, little is known about the formation of -sheets, another equally important structural component. This research will compare the structure, stability and folding of the fragments of thioredoxin and their association products with those of the original protein to elucidate the folding of the still little understood -sheets. ***
