The motor domain determines the large step of myosin-V

Hiroto Tanaka, Kazuaki Homma, Atsuko Hikikoshi Iwane, Eisaku Katayama, Reiko Ikebe, Junya Saito, Toshio Yanagida, Mitsuo Ikebe

Research output: Contribution to journalArticlepeer-review

112 Scopus citations


Class-V myosin proceeds along actin filaments with large (∼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.

Original languageEnglish (US)
Pages (from-to)192-195
Number of pages4
Issue number6868
StatePublished - 2002

ASJC Scopus subject areas

  • General

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