Pressure-temperature-induced denaturation of yeast phosphoglycerate kinase, a double-domain protein.

Pressure-induced denaturation of yeast phosphoglycerate kinase was studied at various temperatures, as a model double-domain protein, using intrinsic fluorescence, 4th derivative absorbance, CD, and DSC. A thermodynamic transition intermediate was observed in the pressure-denaturation, as was reported for the cold denaturation. From the different response of Trp and Tyr residues, as monitored by fluorescence and 4th derivative absorbance changes, the C-terminal domain carrying all the Trp residues seemed to exert structural changes at relatively lower pressure. A further structural change involving both domains was observed at higher pressures. The two-step changes occurred almost simultaneously during heat denaturation.