ATP Hydrolysis in Eg5 Kinesin Involves a Catalytic Two-Water Mechanism
نویسندگان
چکیده
منابع مشابه
Pathway of ATP hydrolysis by monomeric kinesin Eg5.
Kinesin-5 family members including human Eg5/KSP contribute to the plus-end-directed force necessary for the assembly and maintenance of the bipolar mitotic spindle. We have used monomeric Eg5-367 in the nucleotide-free state to evaluate the role of microtubules at each step in the ATPase cycle. The pre-steady-state kinetic results show that the microtubule-Eg5 complex binds MgATP tightly, foll...
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During ATP hydrolysis, myosin or subfragment 1 catalyzes the exchange of oxygens between water and phosphate, so that on average, each product Pi molecule contains more than one oxygen atom derived from water. Using quenched-flow techniques, the exchange process in both ATP and Pi was studied in the rabbit skeletal muscle subfragment 1 ATPase. The exchange in protein-bound ATP (M**ATP) and prot...
متن کاملMonastrol inhibition of the mitotic kinesin Eg5.
Monastrol is a small, cell-permeable molecule that arrests cells in mitosis by specifically inhibiting Eg5, a member of the Kinesin-5 family. We have used steady-state and presteady-state kinetics as well as equilibrium binding approaches to define the mechanistic basis of S-monastrol inhibition of monomeric human Eg5/KSP. In the absence of microtubules (Mts), the basal ATPase activity is inhib...
متن کاملMyosin ATP hydrolysis: a mechanism involving a magnesium chelate complex.
It is suggested that under physiological conditions (> 1 mM Mg(2+)) MgATP binds to myosin to form a chelate involving the two reactive sulfhydryl sites (SH(1) and SH(2)). The stability of the chelate structure results in marked inhibition of the myosin ATPase in the presence of millimolar magnesium ion. The inhibitory effect of magnesium ion can be eliminated chemically by blocking either the S...
متن کاملDimeric Eg5 maintains processivity through alternating-site catalysis with rate-limiting ATP hydrolysis.
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. Microtubul...
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ژورنال
عنوان ژورنال: Biophysical Journal
سال: 2010
ISSN: 0006-3495
DOI: 10.1016/j.bpj.2009.12.3344