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2owm

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Revision as of 08:49, 4 May 2008 by OCA (Talk | contribs)
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Template:STRUCTURE 2owm

Motor domain of Neurospora crassa kinesin-3 (NcKin3)


Overview

Neurospora crassa kinesin NcKin3 belongs to a unique fungal-specific subgroup of small Kinesin-3-related motor proteins. One of its functions appears to be the transport of mitochondria along microtubules. Here, we present the X-ray structure of a C-terminally truncated monomeric construct of NcKin3 comprising the motor domain and the neck linker, and a 3-D image reconstruction of this motor domain bound to microtubules, by cryoelectron microscopy. The protein contains Mg.ADP bound to the active site, yet the structure resembles an ATP-bound state. By comparison with structures of the Kinesin-3 motor Kif1A in different nucleotide states (Kikkawa, M. et al. (2001) Nature (London, U.K.) 411, 439-445), the NcKin3 structure corresponds to the AMPPCP complex of Kif1A rather than the AMPPNP complex. NcKin3-specific differences in the coordination of the nucleotide and asymmetric interactions between adjacent molecules in the crystal are discussed in the context of the unusual kinetics of the dimeric wild-type motor and the monomeric construct used for crystal structure analysis. The NcKin3 motor decorates microtubules at a stoichiometry of one head per alphabeta-tubulin heterodimer, thereby forming an axial periodicity of 8 nm. In spite of unusual extensions at the N-terminus and within flexible loops L2, L8a, and L12 (corresponding to the K-loop of monomeric kinesins), the microtubule binding geometry is similar to that of other members of the kinesin family.

About this Structure

2OWM is a Single protein structure of sequence from Neurospora crassa. Full crystallographic information is available from OCA.

Reference

X-ray Structure and Microtubule Interaction of the Motor Domain of Neurospora crassa NcKin3, a Kinesin with Unusual Processivity(,)., Marx A, Muller J, Mandelkow EM, Woehlke G, Bouchet-Marquis C, Hoenger A, Mandelkow E, Biochemistry. 2008 Feb 19;47(7):1848-1861. Epub 2008 Jan 19. PMID:18205396 Page seeded by OCA on Sun May 4 11:49:06 2008

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