Myosin V walks hand-over-hand: single fluorophore imaging with 1.5-nm localization

Science. 2003 Jun 27;300(5628):2061-5. doi: 10.1126/science.1084398. Epub 2003 Jun 5.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Actin Cytoskeleton / metabolism*
  • Actin Cytoskeleton / ultrastructure
  • Actins / metabolism
  • Adenosine Triphosphate / metabolism
  • Binding Sites
  • Calmodulin
  • Carbocyanines / metabolism
  • Catalytic Domain
  • DNA
  • Fluorescence
  • Fluorescent Dyes / metabolism
  • Kinetics
  • Mathematics
  • Microscopy, Fluorescence
  • Models, Biological*
  • Molecular Motor Proteins / chemistry
  • Molecular Motor Proteins / metabolism*
  • Myosin Light Chains / chemistry
  • Myosin Light Chains / metabolism
  • Myosin Type V / chemistry
  • Myosin Type V / metabolism*
  • Protein Structure, Tertiary
  • Rhodamines / metabolism

Substances

  • Actins
  • Calmodulin
  • Carbocyanines
  • Fluorescent Dyes
  • Molecular Motor Proteins
  • Myosin Light Chains
  • Rhodamines
  • cyanine dye 3
  • Adenosine Triphosphate
  • DNA
  • Myosin Type V