Kinesin motor domain. 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 most kinesins, the motor domain is found at the N-terminus (N-type), in some its is found in the middle (M-type), or C-terminal (C-type). N-type and M-type kinesins are (+) end-directed motors, while C-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. 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.

Cellulose synthase catalytic subunit A2 (CESA2) is a catalytic subunit or a catalytic subunit substitute of the cellulose synthase complex. Cellulose synthase (CESA) catalyzes the polymerization reaction of cellulose using UDP-glucose as the substrate. Cellulose is an aggregate of unbranched polymers of beta-1,4-linked glucose residues, which is an abundant polysaccharide produced by plants and in varying degrees by several other organisms including algae, bacteria, fungi, and even some animals. Genomes from higher plants harbor multiple CESA genes. There are ten in Arabidopsis. At least three different CESA proteins are required to form a functional complex. In Arabidopsis, CESA1, 3 and 6 and CESA4, 7 and 8, are required for cellulose biosynthesis during primary and secondary cell wall formation. CESA2 is very closely related to CESA6 and is viewed as a prime substitute for CESA6. They functionally compensate each other. The cesa2 and cesa6 double mutant plants were significantly smaller, while the single mutant plants were almost normal.

Kinesin motor domain.

Kinesin motor, catalytic domain. ATPase. Microtubule-dependent molecular motors that play important roles in intracellular transport of organelles and in cell division.

Kinesin motor domain, KIF4-like subfamily. Members of this group seem to perform a variety of functions, and have been implicated in neuronal organelle transport and chromosome segregation during mitosis. 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 most kinesins, the motor domain is found at the N-terminus (N-type). N-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. 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.