Tanaka, HirotoHomma, KazuakiIwane, Atsuko HikikoshiKatayama, EisakuIkebe, ReikoSaito, JunyaYanagida, ToshioIkebe, Mitsuo2022-08-232022-08-232002-01-242009-01-13Nature. 2002 Jan 10;415(6868):192-5. <a href="http://dx.doi.org/10.1038/415192a">Link to article on publisher's site</a>0028-0836 (Print)10.1038/415192a11805840https://hdl.handle.net/20.500.14038/32666Class-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.en-USJournal Articlehttps://escholarship.umassmed.edu/gsbs_sp/1226693136gsbs_sp/1226