Abstract:

G-actin was prepared from bovine skeletal muscle and exposed to pressures ranging from 0.1 to 400 MPa. The high pressure-induced structural change of G-actin was explored in terms of fluorescence spectrum, center of spectral mass, the amount of surface sulfhydryl (SH) group and surface aromatic hydrophobicity. The fluorescence intensity of G-actin decreased as pressure increased from 0.1 to 100 MPa; however, an opposite change was observed as pressure increased from 200 to 400 MPa; and the fluorescence spectrum of G-actin exhibited a blue shift due to exposure to higher pressures. As pressure increased from 100 to 300 MPa, the center of spectral mass of G-actin initially decreased slightly, reaching its minimum value at 100 MPa, followed by a rebound increase, and the amount of surface sulfhydryl group gradually increased, and the surface aromatic hydrophobicity changed in a manner similar to that of the amount of surface sulfhydryl group, reaching its maximum value at 300 MPa. Therefore, high pressure-induced three-dimensional structural change of G-actin might be irreversible.

Key words: high pressure, G-actin, center of spectral mass, sulfhydryl group, aromatic hydrophobicity