Modulating the mitogenic activity of the fibroblast growth factor

by Anderson, Joshua L.; Jayanthi, Srinivas; Thallapuranam, Suresh K.

Human acidic fibroblast growth factor (FGF-1) is one of the broadest known mitogens, with the ability to activate the entire range of fibroblast growth factor receptors (FGFR). Through this interaction, FGF-1 is involved in initiating various processes such as organogenesis, angiogenesis, tissue repair, and differentiation. It has been shown that FGF-1 is an inherently unstable mol., with a relatively short half-life and poor thermal stability. FGF-1 is stabilized in vivo by interacting with heparin; this interaction enhances the interaction of FGF-1 with its receptor, shields the protein from proteolytic degrdn., and thermally stabilizes the mol. The 84th position in the wild-type FGF-1 mol. contains an aspartic acid residue. It has been shown that upon interaction with heparin, this residue shifts from ~10 to ~7 angstroms from heparin. Inducing an aspartic acid to arginine mutation at the 84th position in the primary structure of FGF-1 via site-directed mutagenesis and studying the effects of this mutation on the structure, stability, and function retention of this mutant vs. the wild-type form, including its interaction with heparin, to yield information regarding the role of this position and the structure to function relationship of the mol. as a whole is the fundamental intention of this study. Our study employs limited trypsin digestion, differential scanning calorimetry, far UV-CD spectroscopy, 8-anilinonaphthalene-1-sulfonic acid binding assay, and multidimensional NMR spectroscopy techniques on the D84R mutant.