The structure of microtubule motor proteins.

Microtubules are the intracellular tracks for two classes of motor proteins: kinesins and dyneins. During the past few years, the motor domain structures of several kinesins from different organisms have been determined by X-ray crystallography. Compared with kinesins, dyneins are much larger proteins and attempts to crystallize them have failed so far. Structural information about these proteins comes mostly from electron microscopy. In this chapter, we mainly focus on the crystal structures of kinesin motor domains.