1F9T image
Entry Detail
PDB ID:
1F9T
Title:
CRYSTAL STRUCTURES OF KINESIN MUTANTS REVEAL A SIGNALLING PATHWAY FOR ACTIVATION OF THE MOTOR ATPASE
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2000-07-11
Release Date:
2001-06-13
Method Details:
Experimental Method:
Resolution:
1.50 Å
R-Value Free:
0.24
R-Value Work:
0.21
Space Group:
P 1 21 1
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:KINESIN-LIKE PROTEIN KAR3
Mutations:V372M
Chain IDs:A
Chain Length:358
Number of Molecules:1
Biological Source:Saccharomyces cerevisiae
Primary Citation
A structural pathway for activation of the kinesin motor ATPase.
EMBO J. 20 2611 2618 (2001)
PMID: 11387196 DOI: 10.1093/emboj/20.11.2611

Abstact

Molecular motors move along actin or microtubules by rapidly hydrolyzing ATP and undergoing changes in filament-binding affinity with steps of the nucleotide hydrolysis cycle. It is generally accepted that motor binding to its filament greatly increases the rate of ATP hydrolysis, but the structural changes in the motor associated with ATPase activation are not known. To identify the conformational changes underlying motor movement on its filament, we solved the crystal structures of three kinesin mutants that decouple nucleotide and microtubule binding by the motor, and block microtubule-activated, but not basal, ATPase activity. Conformational changes in the structures include a disordered loop and helices in the switch I region and a visible switch II loop, which is disordered in wild-type structures. Switch I moved closer to the bound nucleotide in two mutant structures, perturbing water-mediated interactions with the Mg2+. This could weaken Mg2+ binding and accelerate ADP release to activate the motor ATPASE: The structural changes we observe define a signaling pathway within the motor for ATPase activation that is likely to be essential for motor movement on microtubules.

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