J Molecular Biology 371(1) 256-268 (2007).

[DOI Link]

Spackling the crack: Stabilizing human fibroblast growth factor-1 by targeting the N- and C- terminus β-strand interaction

Department of Biomedical Sciences, Department of Chemistry and Biochemistry, Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida 32306

The β-trefoil protein human fibroblast growth factor-1 (FGF-1) is made up of a six-beta;stranded antiparallel β-barrel closed off on one end by three β-hairpins, thus exhibiting a 3-fold axis of structural symmetry. The N and C terminus β-strands hydrogen bond to each other and their interaction is postulated from both NMR and X-ray structure data to be important in folding and stability. Specific mutations within the adjacent N and C terminus β-strands of FGF-1 are shown to provide a substantial increase in stability. This increase is largely correlated with an increased folding rate constant, and with a smaller but significant decrease in the unfolding rate constant. A series of stabilizing mutations are subsequently combined and result in a doubling of the ΔG value of unfolding. When taken in the context of previous studies of stabilizing mutations, the results indicate that although FGF-1 is known for generally poor thermal stability, the β-trefoil architecture appears capable of substantial thermal stability. Targeting stabilizing mutations within the N and C terminus β-strand interactions of a β-barrel architecture may be a generally useful approach to increase protein stability. Such stabilized mutations of FGF-1 are shown to exhibit significant increases in effective mitogenic potency, and may prove useful as "second generation" forms of FGF-1 for application in angiogenic therapy.

PMID:17570396 [PubMed - indexed for MEDLINE]

This publication is one of the several that describes a structure solved either at the Kasha Laboratory, Institute of Molecular Biophysics or in collaboration with the Institute Faculty. The data used for this structure determination came in full or part from the Macromolecular X-Ray Crystallography Facility.