Native dimer stabilizes the subunit tertiary structure of porcine class pi glutathione S-transferase.
Solvent-induced unfolding of porcine class pi glutathione S-transferase (pGST P1-1), a homodimeric protein, was monitored under equilibrium conditions using different physicochemical parameters (tryptophan fluorescence, anisotropy, degree of tyrosine exposure, binding of 8-anilino-1-naphthalenesulphonic acid, size-exclusion HPLC). The coincidence of unfolding curves obtained with functional (enzyme activity) and structural probes (anisotropy), the absence of thermodynamically stable intermediates such as a folded monomer (determined by binding of 8-anilino-1-naphthalenesulphonic acid and size-exclusion HPLC), and the dependence of pGST P1-1 stability upon protein concentration (measured with structural and functional probes), indicate a cooperative and concerted two-state unfolding transition between native dimeric pGST P1-1 and unfolded monomeric enzyme.
Erhardt
J
J
Department of Biochemistry, University of the Witwatersrand, Johannesburg, South Africa.
Dirr
H
H
D000817:Anilino Naphthalenesulfonates; D000818:Animals; D001704:Biopolymers; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D004795:Enzyme Stability; D005454:Fluorescence Polarization; D005456:Fluorescent Dyes; D005982:Glutathione Transferase / Q000737:chemistry*; D011487:Protein Conformation; D017510:Protein Folding; D013552:Swine; D013816:Thermodynamics
D000817:Anilino Naphthalenesulfonates; D001704:Biopolymers; D005456:Fluorescent Dyes; C027132:1-anilino-8-naphthalenesulfonate; D005982:Glutathione Transferase