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Equilibrium studies of kinesin-nucleotide intermediates
S S Rosenfeld1, B Rener, J J Correia
1Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA.
The Journal of Biological Chemistry
|April 19, 1996
Summary
Kinesin
Area of Science:
- Biochemistry
- Molecular Biology
- Cell Biology
Background:
- Kinesin is a motor protein crucial for intracellular transport.
- Understanding kinesin's interaction with microtubules and nucleotides is key to deciphering its motility mechanism.
Purpose of the Study:
- To investigate the energetics of kinesin-microtubule and kinesin-nucleotide interactions.
- To develop a structural model for kinesin-dependent motility.
Main Methods:
- Studied kinesin constructs with varying nucleotide states and microtubule binding.
- Measured effects of dimerization, beryllium fluoride, aluminum fluoride, and inorganic phosphate on kinesin ATPase activity and microtubule affinity.
Main Results:
- Kinesin dimerization reduced microtubule-activated ATPase rate 5-fold.
- Fluoride compounds decreased ATPase rate but increased microtubule affinity.
- Inorganic phosphate decreased dimeric kinesin's microtubule affinity.
- Kinesin heads exhibit "strong" and "weak" binding states influenced by nucleotide occupancy.
Conclusions:
- Kinesin motility involves conformational changes between strong and weak binding states.
- ATP hydrolysis and subsequent phosphate release are critical steps in kinesin detachment from microtubules.
- The formation of kinesin.ADP.P(i) represents a significant energy change driving kinesin dissociation.