Dimeric Eg5 maintains processivity through alternating-site catalysis with rate-limiting ATP hydrolysis.

ABSTRACT: Eg5/KSP is a homotetrameric, Kinesin-5 family member whose ability to cross-link microtubules has associated it with mitotic spindle assembly and dynamics for chromosome segregation. Transient-state kinetic methodologies have been used to dissect the mechanochemical cycle of a dimeric motor, Eg5-513, to better understand the cooperative interactions that modulate processive stepping. Microtubule association, ADP release, and ATP binding are all fast steps in the pathway. However, the acid-quench analysis of the kinetics of ATP hydrolysis with substrate in excess of motor was unable to resolve a burst of product formation during the first turnover event. In addition, the kinetics of P(i) release and ATP-promoted microtubule-Eg5 dissociation were observed to be no faster than the rate of ATP

SUBMITTER: Krzysiak TC 

PROVIDER: S-EPMC1866285 | biostudies-literature | 2006 Dec

REPOSITORIES: biostudies-literature