Laser raman spectroscopy--new probe of myosin substructure.

Laser Raman spectroscopy is used to probe the heterogeneous substructure of the large contractile protein myosin. Some peaks are assigned to specific chemical groups of the molecule; others, notably the conformationally sensitive amide III vibrations, provide information on the structurally distinct regions of the molecule. Deuteration of the NH groups is instrumental in the assignment of these vibrational modes. The relative intensities of bands typical of alpha-helical conformations (near 1265 and 1304 cm-1) and bands associated with nonhelical structure (near 1244 cm-1) are sensitive indicators of myosin substructure and represent potentially useful probes of conformational changes.