15 A resolution model of the monomeric kinesin motor, KIF1A

Cell. 2000 Jan 21;100(2):241-52. doi: 10.1016/s0092-8674(00)81562-7.


A two-headed structure has been widely believed to be essential for the kinesin molecular motor to move processively on the track, microtubules. However, we have recently demonstrated that a monomeric motor domain construct of KIF1A (C351), a kinesin superfamily protein, moves processively, taking about 700 steps before being detached from microtubules. To elucidate the mechanism of its single-headed processivity, we examined the C351 -MT interaction by mutant analysis and high-resolution cryo-EM. Mutant analysis indicated the importance of a highly positively charged loop, the "K loop," for such processivity. A 15 A resolution structure unambiguously docked with the available atomic models revealed "K loop" as an extra microtubule-binding domain specific to KIF1A, and bound to the C terminus of tubulin. The site-specific cross-linking further confirmed this model.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Binding Sites / physiology
  • Cross-Linking Reagents / chemistry
  • Cross-Linking Reagents / metabolism
  • Gold / chemistry
  • Humans
  • Image Processing, Computer-Assisted
  • Kinesin / chemistry*
  • Kinesin / genetics*
  • Kinesin / metabolism
  • Microscopy, Electron
  • Microtubules / chemistry
  • Microtubules / ultrastructure
  • Models, Chemical*
  • Molecular Motor Proteins / chemistry*
  • Molecular Motor Proteins / genetics*
  • Molecular Motor Proteins / metabolism
  • Molecular Sequence Data
  • Mutagenesis
  • Nerve Tissue Proteins / chemistry*
  • Nerve Tissue Proteins / genetics*
  • Nerve Tissue Proteins / metabolism
  • Protein Structure, Quaternary
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Sequence Homology, Amino Acid
  • Tubulin / chemistry
  • Tubulin / metabolism


  • Cross-Linking Reagents
  • KIF1A protein, human
  • Molecular Motor Proteins
  • Nerve Tissue Proteins
  • Tubulin
  • Gold
  • Kinesin