Heterologous expression of a cardiomyopathic myosin that is defective in its actin interaction.

摘要: Abstract A point mutation in the heavy chain of cardiac myosin, resulting replacement an arginine (Arg) with glutamine (Gln), has been linked to hypertrophic cardiomyopathy humans (Geisterfer-Lowrance, A. T., Kass, S., Tanigawa, G., Vosberg, H.-P., McKenna, W., Seidman, J. and C. E. (1990) Cell 62, 999-1006). To determine functional impact this mutation, baculovirus-driven coexpression myosin light chains developed. The Arg-403-->Gln resulted normal ATPase activity absence actin. However, presence actin, was greatly reduced (Vmax decreased > 3.5-fold K(app) increased 3-fold). In vitro motility nearly 5-fold by single amino acid mutation. Thus, Arg-403 likely contributes important interaction at actin interface myosin. Replacement Gln leads rate(s) transition within actin-myosin crossbridge cycle. humans, will result power output per unit area muscle, providing a stimulus for hypertrophy.