Kinesins most resembled myosins, the motor proteins responsible for muscle contraction. That result surprised Vale because the two molecules differ in size, amino acid sequence, and movement style. The results suggest that kinesins and myosins may have diverged long ago during their evolution. It may be that nature found a good solution and kept it. The structural similarity between kinesins and myosins supports the idea that motors may be modular, with a similar fuel-burning domain that is joined to unique regions for carrying cargo.
Motor proteins work hard and fast.
Kinesin, for example, moves protein building blocks from their birth sites to far points in the cell. In the case of a nerve cell, this journey may stretch three feet long. Kinesin molecules can move at the blinding rate of 100 body lengths per second. Though kinesin and ncd are highly similar molecules, their small differences direct them along microtubules in opposite directions. Ncd builds the mitotic spindle and segregates chromosomes prior to cell division.