The motor domain determines the large step of myosin-V
Graduate School of Biomedical Sciences; Department of Physiology
Life Sciences | Medicine and Health Sciences
Class-V myosin proceeds along actin filaments with large ( approximately 36 nm) steps. Myosin-V has two heads, each of which consists of a motor domain and a long (23 nm) neck domain. In accordance with the widely accepted lever-arm model, it was suggested that myosin-V steps to successive (36 nm) target zones along the actin helical repeat by tilting its long neck (lever-arm). To test this hypothesis, we measured the mechanical properties of single molecules of myosin-V truncation mutants with neck domains only one-sixth of the native length. Our results show that the processivity and step distance along actin are both similar to those of full-length myosin-V. Thus, the long neck domain is not essential for either the large steps or processivity of myosin-V. These results challenge the lever-arm model. We propose that the motor domain and/or the actomyosin interface enable myosin-V to produce large processive steps during translocation along actin.
DOI of Published Version
Nature. 2002 Jan 10;415(6868):192-5. Link to article on publisher's site
Tanaka H, Homma K, Iwane AH, Katayama E, Ikebe R, Saito J, Yanagida T, Ikebe M. (2002). The motor domain determines the large step of myosin-V. GSBS Student Publications. https://doi.org/10.1038/415192a. Retrieved from https://escholarship.umassmed.edu/gsbs_sp/1226