Structures of kinesin and kinesin-microtubule interactions

Several X-ray crystal structures of kinesin motor domains have recently bee n solved at high resolution (similar to 0.2-0.3 nm), in both their monomeri c and dimeric states. They show the folding of the polypeptide chain and di fferent arrangements of subunits in the dimer. in addition, cryo-electron m icroscopy and image reconstruction have revealed microtubules decorated wit h kinesin at intermediate resolution (similar to 2 nm), showing the distrib ution and orientation of kinesin heads on the microtubule surface. The comp arison of the X-ray and electron microscopy results yields a model of how m onomeric motor domains bind to the microtubule but the binding of dimeric m otors, their stoichiometry, or the influence of nucleotides remains a matte r of debate.