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Motor domain of Neurospora crassa kinesin-3 (NcKin3)Motor domain of Neurospora crassa kinesin-3 (NcKin3)
Structural highlights
FunctionEvolutionary ConservationCheck, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedNeurospora 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. 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[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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