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Multiple pathways for denaturation of horse plasma gelsolin

TitleMultiple pathways for denaturation of horse plasma gelsolin
Publication TypeJournal Article
Year of Publication1996
AuthorsKoepf, EK, Burtnick, LD
JournalBiochemistry and Cell Biology-Biochimie Et Biologie Cellulaire
Volume74
Pagination101-107
Type of ArticleArticle
ISBN Number0829-8211
KeywordsACTIN-BINDING-SITES, calcium, chemical, circular dichroism, denaturation, FLUORESCEIN ISOTHIOCYANATE, gelsolin, PROTEIN, thermal
Abstract

Gelsolin purified from horse plasma carries a surface charge distribution that greatly influences how the protein unfolds, aggregates, or precipitates as a function of temperature or concentration of chemical denaturant. Modification of gelsolin with fluorescein isothiocyanate replaces positive charges on amine groups with bulky, negatively charged fluorescein moieties. This postpones thermally induced precipitation by about 10 degrees C [Koepf, E.K., and Burtnick, L.D. 1993. Eur. J. Biochem. 212: 713-718]. Interaction with cations such as Ca2+ or guanidinium(+) also alters the surface charge on gelsolin. This affects the structure of the protein in solution, modifies the pathway for unfolding, and moderates the onset of precipitation induced by chemical denaturants or heat. Denaturation of gelsolin is not interpretable in terms of a simple two-state cooperative mechanism. The pathway to a denatured state and intermediate structures present along the way depend upon the agent used to unfold the protein.

URL<Go to ISI>://A1996UE60500011