Muscle myosins require both heads to generate maximal force and motion, with double-headed myosin producing twice the displacement and force of single-headed myosin.
Both heads required for maximal myosin force; extends cross-bridge mechanics but leaves open relevance to human cardiac sarcomeres.
Several classes of the myosin superfamily are distinguished by their "double-headed" structure, where each head is a molecular motor capable of hydrolyzing ATP and interacting with actin to generate force and motion. The functional significance of this dimeric structure, however, has eluded investigators since its discovery in the late 1960s. Using an optical-trap transducer, we have measured the unitary displacement and force produced by double-headed and single-headed smooth- and skeletal-muscle myosins. Single-headed myosin produces approximately half the displacement and force (approximately 6 nm; 0.7 pN) of double-headed myosin (approximately 10 nm; 1.4 pN) during a unitary interaction with actin. These data suggest that muscle myosins require both heads to generate maximal force and motion.
No takes yet. Share an insight, caveat, or question.
Tyska et al. (1999) studied this question.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: