tailieunhanh - Báo cáo khoa học: Use of hydrostatic pressure to produce ‘native’ monomers of yeast enolase

The effects of hydrostatic pressure on yeast enolase have been studied in the presence of 1 mMMn2+ . When com-pared with apo-enolase, and Mg-enolase, the Mn-enzyme differs from the others in three ways. Exposure to hydro-static pressure does not inactivate the enzyme. If the experiments are performed in the presence of 1 mMMg2+ , or with apo-enzyme, the enzyme is inactivated [Kornblatt, ., Lange R., Balny C. (1998)Eur. J. Biochem251, 775– 780]. The UV spectra of the high pressure forms of the Mg2+ - and apo-forms of enolase are identical and distinct from the spectrum of the form obtained in the presence of 1mMMn2+ ; . | Eur. J. Biochem. 271 3897-3904 2004 FEBS 2004 doi Use of hydrostatic pressure to produce native monomers of yeast enolase M. Judith Kornblatt1 Reinhard Lange2 and Claude Balny2 1Department of Chemistry and Biochemistry Concordia University Montreal Quebec Canada 2INSERM Unite 128 IFR 122 Montpellier France The effects of hydrostatic pressure on yeast enolase have been studied in the presence of 1 mM Mn2 . When compared with apo-enolase and Mg-enolase the Mn-enzyme differs from the others in three ways. Exposure to hydrostatic pressure does not inactivate the enzyme. If the experiments are performed in the presence of 1 mM Mg2 or with apo-enzyme the enzyme is inactivated Kornblatt . Lange R. Balny C. 1998 Eur. J. Biochem 251 775780 . The UV spectra of the high pressure forms of the Mg2 - and apo-forms of enolase are identical and distinct from the spectrum of the form obtained in the presence of 1 mM Mn2 this suggests that Mn2 remains bound to the high pressure form of enolase. With Mn-enolase the various spectral changes do not occur in the same pressure range indicating that multiple processes are occurring. Pressure experiments were performed as a function of Mn2 and protein . One of the changes in the UV spectra shows a dependence on protein concentration indicating that enolase is dissociating into monomers. The small changes in the UV spectrum and the retention of activity lead to a model in which enolase in the presence of high concentrations of Mn2 dissociates into native monomers upon release of pressure the enzyme is fully active. Although further spectral changes occur at higher pressures there is no inactivation as long as Mn2 remains bound. We propose that the relatively small and polar nature of the subunit interface of yeast enolase including the presence of several salt bridges is responsible for the ability of hydrostatic pressure to dissociate this enzyme into monomers with a native-like structure. Keywords .