Laser Raman Light-Scattering Observations of Conformational Changes in Myosin Induced by Inorganic Salts

The Raman spectra of aqueous solutions of myosin and mixtures of myosin in solutions of the salts CaCl2, MgCl2, and LiBr have been taken. The spectrum of the solvent background has been subtracted by means of a computer, leaving only the Raman peaks of the protein. From an analysis of the Raman bands in the regions at 900, 940, 1,240–1,300, and 1,650–1,670cm-1, it seems likely that CaCl2 effects an α-to β-transition in myosin, probably owing to the interaction of the Ca2+ ion, LiBr appears to denature the protein leading to increased random coil structure, and MgCl2 appears to have an effect intermediate between the two other salts. These results are reported for concentrations as low as 10-5 M of CaCl2 and MgCl2.This investigation indicates the usefulness of the Raman light-scattering technique for the study of protein conformational changes