Loop L5 Acts as a Conformational Latch in the Mitotic Kinesin Eg5

All members of the kinesin superfamily of molecular motors contain an unusual structural motif consisting of an α-helix that is interrupted by a flexible loop, referred to as L5. We have examined the function of L5 in the mitotic kinesin Eg5 by combining site-directed mutagenesis of L5 with transien...

Full description

Saved in:
Bibliographic Details
Published inThe Journal of biological chemistry Vol. 286; no. 7; pp. 5242 - 5253
Main Authors Behnke-Parks, William M., Vendome, Jeremie, Honig, Barry, Maliga, Zoltan, Moores, Carolyn, Rosenfeld, Steven S.
Format Journal Article
LanguageEnglish
Published United States Elsevier Inc 18.02.2011
American Society for Biochemistry and Molecular Biology
Subjects
Animals
Catalytic Domain
Computer Simulation
Electron Microscopy (EM)
Fluorescence
Fluorescence Resonance Energy Transfer (FRET)
Humans
Kinesin
Kinesins - chemistry
Kinesins - genetics
Kinetics
Models, Molecular
Molecular Dynamics
Molecular Motors
Mutagenesis, Site-Directed
Protein Structure and Folding
Protein Structure, Secondary
Molecular Dynamics
Molecular Motors
Fluorescence
Fluorescence Resonance Energy Transfer (FRET)
Kinetics
Electron Microscopy (EM)
Kinesin
Online AccessGet full text

Cover

More Information
Summary:All members of the kinesin superfamily of molecular motors contain an unusual structural motif consisting of an α-helix that is interrupted by a flexible loop, referred to as L5. We have examined the function of L5 in the mitotic kinesin Eg5 by combining site-directed mutagenesis of L5 with transient state kinetics, molecular dynamics simulations, and docking using cryo electron microscopy density. We find that mutation of a proline residue located at a turn within this loop profoundly slows nucleotide-induced structural changes both at the catalytic site as well as at the microtubule binding domain and the neck linker. Molecular dynamics simulations reveal that this mutation affects the dynamics not only of L5 itself but also of the switch I structural elements that sense ATP binding to the catalytic site. Our results lead us to propose that L5 regulates the rate of conformational change in key elements of the nucleotide binding site through its interactions with α3 and in so doing controls the speed of movement and force generation in kinesin motors.
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.M110.192930