title: The prepower stroke conformation of myosin V.
abstract: We have used electron microscopy and single-particle image processing to study head conformation in myosin V molecules. We find that in the presence of ATP, many heads have a sharply angled conformation that is rare in its absence. The sharply angled conformation is similar to a myosin II atomic structure proposed to mimic the prepower stroke state. The leading head in molecules attached to actin by both heads has a similar conformation, but is also sharply angled in a second plane by tethering through the trail head. The lead head lever joins the motor domain approximately 5 nm axially from where it joins the trail motor. These positions locate the converter subdomain and show the lead motor is in the prepower stroke conformation. Tethering by the trail head places the lead head motor domain at the correct axial position along the actin for binding, but at the wrong orientation. Attachment is achieved either by bending the lead head lever throughout its length or at the pliant point. The microscopy shows that most of the walking stride is produced by changes in lever angle brought about by converter movement, but is augmented by distortion produced by thermal energy.
authors.affiliation: Astbury Centre for Structural Molecular Biology and School of Biomedical Sciences, University of Leeds, Leeds, UK.
authors.forename: Stan
authors.initials: S
authors.lastname: Burgess
authors.forename: Matt
authors.initials: M
authors.lastname: Walker
authors.forename: Fei
authors.initials: F
authors.lastname: Wang
authors.forename: James R
authors.initials: JR
authors.lastname: Sellers
authors.forename: Howard D
authors.initials: HD
authors.lastname: White
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Knight
authors.forename: John
authors.initials: J
authors.lastname: Trinick
mesh_terms: D000199:Actins / Q000737:chemistry; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002460:Cell Line; D018360:Crystallography, X-Ray; D006358:Hot Temperature; D006868:Hydrolysis; D007313:Insecta; D051379:Mice; D008854:Microscopy, Electron; D008958:Models, Molecular; D024462:Myosin Type II / Q000737:chemistry; D024701:Myosin Type V / Q000737:chemistry*; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary
chemical_list: D000199:Actins; D000255:Adenosine Triphosphate; D024462:Myosin Type II; D024701:Myosin Type V