[Secondary structure and amino acid composition of protein complex associated with the rod part of myosin molecule]

The secondary structure and amino acid composition of a protein complex (LMM-Rp) bound to the heavy chains (HC) of light meromyosin (LMM), and the secondary structures of LMM and its fractions obtained at an intermediate stage of LMM-Rp preparation were studied. The data obtained were compared with the similar ones for LMM HC and for the myosin light chains (LC). For the secondary structure study the data of CD-spectra were used. This structure was characterized by molar parts of the amino acid residues belonging to four different conformations: alpha-helices, beta-structures, beta-bends and irregular coils. In LMM-Rp unlike HC and LC, the alpha-helices are nearly absent, and appreciable parts of irregular coils and beta-bends are present. The amino acid compositions of LMM-Rp, HC and LC markedly differ. This difference is more significant when LMM-Rp is compared with HC, then with LC. This is an accordance with comparable data for the secondary structure.