A combination of near- and far-UV circular dichroism, Fourier-transform infrared spectroscopy, tryptophan fluorescence, size-exclusion chromatography, and a fluorescent extrinsic hydrophobic probe has been employed to characterize partially structured states of human recombinant acidic fibroblast growth factor (aFGF). At low pH, the addition of specific polyanionic ligands or moderate amounts of salts induces states with high secondary but low tertiary structure content. At neutral pH, intermediate amounts of chaotropic agents impose similar partially structured conformational states which also display noncooperative unfolding transitions. Kinetic evidence indicates that similar forms of the protein exist in the first few hundred milliseconds in the refolding pathway of aFGF. The kinetics of their formation appear to be temperature-independent, implying lack of an energy barrier, which is characteristic for further slow folding into the native state. Unlike the native and fully unfolded states, these partially structured conformations exhibit very low solubility, resulting in irreversible aggregation. Potential physiological implications of the existence of such "molten globule" states with regard to the growth factor's transport and biological activity are considered. Study holds ProTherm entries: 4561 Extra Details: additive : EDTA(0.1 mM), tertiary structure; conformational states; noncooperative;,solubility; molten globule
Submitter: Connie Wang
Submission Date: April 24, 2018, 8:26 p.m.
|Number of data points||2|
|Proteins||Fibroblast growth factor 2 ; Fibroblast growth factor 2|
|Assays/Quantities/Protocols||Experimental Assay: Cm ; Experimental Assay: dG_H2O|
|Libraries||Mutations for sequence PALPEDGGSGAFPPGHFKDPKRLYCKNGGFFLRIHPDGRVDGVREKSDPHIKLQLQAEERGVVSIKGVCANRYLAMKEDGRLLASKCVTDECFFFERLESNNYNTYRSRKYTSWYVALKRTGQYKLGSKTGPGQKAILFLPMSAKS|