| Summary: | 博士 === 國立清華大學 === 化學系 === 91 === The present study describes the characterization of a near native equilibrium intermediate state present in the unfolding pathway of acidic human fibroblast growth factor (hFGF-1). The first chapter provides an elaborate introduction to the various topics, which are relevant to the research described in this study. The second chapter of this thesis talks about the expression, purification and characterization of FGF-1. A detailed report of the identification and characterization of structure and dynamics of the equilibrium intermediate in the unfolding pathway of hFGF-1 is provided in Chapter-III of the thesis. Using a variety of biophysical techniques including multidimensional NMR spectroscopy, the equilibrium intermediate is shown to have structural features resembling that of the native state. Chapter-IV of the thesis deals with a comparison of the structural and folding properties of human fibroblast growth factor (hFGF-1) and newt fibroblast growth factor (nFGF-1). The two homologues of FGF-1 are structurally similar, but yet their stabilities and folding pathway(s) are significantly different. The near-native intermediate, which is significantly populated around 1M Guanidine hydrochloride in the unfolding pathway of hFGF-1 is found to be destabilized or absent in the GdnHCl-induced equilibrium-unfolding pathway of nFGF-1. An attempt has been made to address the question of the disparity in the folding behavior of hFGF-1 and nFGF-1. The influence of the chaperonin, GroEL, on the folding of hFGF-1 is described in Chapter-V of the thesis. GroEL is found to have differential effects on the stability of the native and the intermediate states of hFGF-1. Using a variety of biophysical techniques and multi-dimensional NMR spectroscopy, a possible mechanism for the chaperone-assisted folding of hFGF-1 has been described. The research described in this thesis offers several new leads, which could be exploited to evolve general rules to describe the folding properties of b-trefoil proteins.
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