Abstract
Whereas most kinesins motor along microtubules, KinI kinesins are microtubule depolymerizing machines. Surprisingly, we found that a KinI fragment consisting of only the motor core is capable of ATP-dependent depolymerization. The motor binds along microtubules in all nucleotide states, but in the presence of AMPPNP, microtubule depolymerization also occurs. Structural characterization of the products of AMPPNP-induced destabilization revealed a snapshot of the disassembly machine in action as it precisely deformed a tubulin dimer. While conventional kinesins use the energy of ATP binding to execute a "powerstroke," KinIs use it to bend the underlying protofilament. Thus, the relatively small class-specific differences within the KinI motor core modulate a fundamentally conserved mode of interaction with microtubules to produce a unique depolymerizing activity.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Adenosine Triphosphate / metabolism
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Adenylyl Imidodiphosphate / metabolism
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Animals
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Biomechanical Phenomena
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Biopolymers / metabolism
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Dimerization
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Kinesins / chemistry
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Kinesins / metabolism*
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Macromolecular Substances
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Microscopy, Electron
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Microtubules / metabolism*
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Models, Chemical
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Models, Molecular
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Molecular Motor Proteins / metabolism*
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Peptide Fragments / chemistry
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Peptide Fragments / metabolism
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Plasmodium falciparum / metabolism*
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Protein Conformation
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Protein Interaction Mapping
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Protein Structure, Tertiary
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Protozoan Proteins / chemistry
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Protozoan Proteins / metabolism*
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Recombinant Fusion Proteins / chemistry
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Recombinant Fusion Proteins / metabolism
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Tubulin / chemistry
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Tubulin / metabolism*
Substances
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Biopolymers
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Macromolecular Substances
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Molecular Motor Proteins
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Peptide Fragments
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Protozoan Proteins
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Recombinant Fusion Proteins
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Tubulin
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Adenylyl Imidodiphosphate
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Adenosine Triphosphate
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Kinesins