Kinesins consume ATP to power the motor which allows them to move along microtubules. The motor region contains highly conserved Switch 1 (SSRSH) and 2 (DLAGSE) motifs which change conformation during ATP hydrolysis (Rice et al. 1999). These form a salt-bridge that, in myosin, closes the nucleotide-binding cleft, enabling the motor to hydrolyze ATP (Geeves & Holmes 1999). This closed conformation has now been seen by cryo-electron microscopy in human conventional kinesin (Sindelar & Downing 2010) and in a crystal structure of the frog kinesin-5 Eg5 (Parke et al. 2010).