Effects of different NaCl concentrations on self-assembly of silver carp myosin

The effect of NaCl (0.1 − 3.0 M) on self-assembly of silver carp myosin at 4 °C was investigated in terms of microstructure, conformation, intermolecular interactions, and particle size distribution. During setting at 4 °C, the self-assembly of myosin showed an obvious concentration dependence. At low concentrations (<0.3 M), myosin assembled into filaments mainly through rod-rod ionic linkages, and showed significantly (P < 0.05) higher turbidity and lower solubility than at ≥0.3 M. The addition of NaCl (0.3 − 0.6 M) led to the extension and dissolution of myosin by interfering with electrostatic interactions. The myosin assemblies gradually became smaller and more uniform. The solubility and Ca2+-ATPase activity reached a maximum at 0.6 M NaCl. When the concentrations increased to >1.0 M, myosin further assembled into filaments dominated by hydrophobic interactions. Both rod-rod and head-head interactions contributed to the myosin filaments at high concentrations (1.0 − 3.0 M). The solubility and uniformity of the myosin assemblies decreased as the NaCl concentration increased from 1.0 to 3.0 M.