Myosin V walks hand-over-hand: single fluorophore imaging with 1.5-nm localization.
Myosin V is a dimeric molecular motor that moves processively on actin, with the center of mass moving approximately 37 nanometers for each adenosine triphosphate hydrolyzed. We have labeled myosin V with a single fluorophore at different positions in the light-chain domain and measured the step size with a standard deviation of <1.5 nanometers, with 0.5-second temporal resolution, and observation times of minutes. The step size alternates between 37 + 2x nm and 37 - 2x, where x is the distance along the direction of motion between the dye and the midpoint between the two heads. These results strongly support a hand-over-hand model of motility, not an inchworm model.
Yildiz
Ahmet
A
Center for Biophysics and Computational Biology, University of Illinois, Urbana-Champaign, IL 61801, USA.
Forkey
Joseph N
JN
McKinney
Sean A
SA
Ha
Taekjip
T
Goldman
Yale E
YE
Selvin
Paul R
PR
D008841:Actin Cytoskeleton / Q000378:metabolism* / Q000648:ultrastructure; D000199:Actins / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D001665:Binding Sites; D002147:Calmodulin; D002232:Carbocyanines / Q000378:metabolism; D020134:Catalytic Domain; D004247:DNA; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000378:metabolism; D007700:Kinetics; D008433:Mathematics; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D020409:Molecular Motor Proteins / Q000737:chemistry / Q000378:metabolism*; D018994:Myosin Light Chains / Q000737:chemistry / Q000378:metabolism; D024701:Myosin Type V / Q000737:chemistry / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D012235:Rhodamines / Q000378:metabolism
D000199:Actins; D002147:Calmodulin; D002232:Carbocyanines; D005456:Fluorescent Dyes; D020409:Molecular Motor Proteins; D018994:Myosin Light Chains; D012235:Rhodamines; C089187:cyanine dye 3; D000255:Adenosine Triphosphate; D004247:DNA; D024701:Myosin Type V