4ETP image
Deposition Date 2012-04-24
Release Date 2012-06-27
Last Version Date 2024-11-20
Entry Detail
PDB ID:
4ETP
Keywords:
Title:
C-terminal motor and motor homology domain of Kar3Vik1 fused to a synthetic heterodimeric coiled coil
Biological Source:
Source Organism:
Host Organism:
Method Details:
Experimental Method:
Resolution:
2.30 Å
R-Value Free:
0.24
R-Value Work:
0.20
R-Value Observed:
0.20
Space Group:
P 21 21 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:Kinesin-like protein KAR3
Gene (Uniprot):KAR3
Mutations:C391L, C469A, C517A, C566V, C655V)
Chain IDs:A
Chain Length:403
Number of Molecules:1
Biological Source:Saccharomyces cerevisiae
Polymer Type:polypeptide(L)
Molecule:Spindle pole body-associated protein VIK1
Gene (Uniprot):VIK1
Mutations:C377V, C436A, C536A, C596A, C640A, E355C, K423C)
Chain IDs:B
Chain Length:333
Number of Molecules:1
Biological Source:Saccharomyces cerevisiae
Primary Citation
Kar3Vik1, a member of the kinesin-14 superfamily, shows a novel kinesin microtubule binding pattern.
J.Cell Biol. 197 957 970 (2012)
PMID: 22734002 DOI: 10.1083/jcb.201201132

Abstact

Kinesin-14 motors generate microtubule minus-end-directed force used in mitosis and meiosis. These motors are dimeric and operate with a nonprocessive powerstroke mechanism, but the role of the second head in motility has been unclear. In Saccharomyces cerevisiae, the Kinesin-14 Kar3 forms a heterodimer with either Vik1 or Cik1. Vik1 contains a motor homology domain that retains microtubule binding properties but lacks a nucleotide binding site. In this case, both heads are implicated in motility. Here, we show through structural determination of a C-terminal heterodimeric Kar3Vik1, electron microscopy, equilibrium binding, and motility that at the start of the cycle, Kar3Vik1 binds to or occludes two αβ-tubulin subunits on adjacent protofilaments. The cycle begins as Vik1 collides with the microtubule followed by Kar3 microtubule association and ADP release, thereby destabilizing the Vik1-microtubule interaction and positioning the motor for the start of the powerstroke. The results indicate that head-head communication is mediated through the adjoining coiled coil.

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