Kinesin motor domain, KIF2-like group. KIF2 is a protein expressed in neurons, which has been associated with axonal transport and neuron development; alternative splice forms have been implicated in lysosomal translocation. This catalytic (head) domain has ATPase activity and belongs to the larger group of P-loop NTPases. Kinesins are microtubule-dependent molecular motors that play important roles in intracellular transport and in cell division. In this subgroup the motor domain is found in the middle (M-type) of the protein chain. M-type kinesins are (+) end-directed motors, i.e. they transport cargo towards the (+) end of the microtubule. Kinesin motor domains hydrolyze ATP at a rate of about 80 per second, and move along the microtubule at a speed of about 6400 Angstroms per second (KIF2 may be slower). To achieve that, kinesin head groups work in pairs. Upon replacing ADP with ATP, a kinesin motor domain increases its affinity for microtubule binding and locks in place. Also, the neck linker binds to the motor domain, which repositions the other head domain through the coiled-coil domain close to a second tubulin dimer, about 80 Angstroms along the microtubule. Meanwhile, ATP hydrolysis takes place, and when the second head domain binds to the microtubule, the first domain again replaces ADP with ATP, triggering a conformational change that pulls the first domain forward.
Jiyao W et al.(2023). "The conserved domain database in 2023.",