title: Simultaneous measurement of nucleotide occupancy and mechanical displacement in myosin-V, a processive molecular motor.
abstract: Adenosine triphosphate (ATP) turnover drives various processive molecular motors and adenosine diphosphate (ADP) release is a principal transition in this cycle. Biochemical and single molecule mechanical studies have led to a model in which a slow ADP release step contributes to the processivity of myosin-V. To test the relationship between force generation and ADP release, we utilized optical trapping nanometry and single molecule total internal reflection fluorescence imaging for simultaneous and direct observation of both processes in myosin-V. We found that ADP was released 69 +/- 5.3 ms after force generation and displacement of actin, providing direct evidence for slow ADP release. As proposed by several previous studies, this slow ADP release probably ensures processivity by prolonging the strong actomyosin state in the ATP turnover cycle.
authors.affiliation: Laboratories for Nanobiology, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan.
authors.forename: Tomotaka
authors.initials: T
authors.lastname: Komori
authors.forename: So
authors.initials: S
authors.lastname: Nishikawa
authors.forename: Takayuki
authors.initials: T
authors.lastname: Ariga
authors.forename: Atsuko Hikikoshi
authors.initials: AH
authors.lastname: Iwane
authors.forename: Toshio
authors.initials: T
authors.lastname: Yanagida
mesh_terms: D000199:Actins / Q000378:metabolism; D000244:Adenosine Diphosphate / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism; D005453:Fluorescence; D006801:Humans; D007211:Indoles / Q000378:metabolism; D055595:Mechanical Phenomena; D018995:Myosin Heavy Chains / Q000378:metabolism*; D024701:Myosin Type V / Q000378:metabolism*; D052898:Optical Tweezers; D013997:Time Factors
chemical_list: C106705:3'(2')-O-(N-(2-((2-((1-ethyl-3,3-dimethyl-5-sulfoindol-2-yl)prop-2-enylidene)-3,3-dimethyl-5-sulfoindol-1-yl)amino)ethyl)carbamoyl)-adenosine triphosphate; D000199:Actins; D007211:Indoles; C077511:MYO5A protein, human; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D024701:Myosin Type V; D018995:Myosin Heavy Chains