Abstract
FtsK is a DNA translocase that coordinates chromosome segregation and cell division in bacteria. In addition to its role as activator of XerCD site-specific recombination, FtsK can translocate double-stranded DNA (dsDNA) rapidly and directionally and reverse direction. We present crystal structures of the FtsK motor domain monomer, showing that it has a RecA-like core, the FtsK hexamer, and also showing that it is a ring with a large central annulus and a dodecamer consisting of two hexamers, head to head. Electron microscopy (EM) demonstrates the DNA-dependent existence of hexamers in solution and shows that duplex DNA passes through the middle of each ring. Comparison of FtsK monomer structures from two different crystal forms highlights a conformational change that we propose is the structural basis for a rotary inchworm mechanism of DNA translocation.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adenosine Triphosphate / metabolism
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Crystallography, X-Ray
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DNA Helicases / metabolism
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DNA, Bacterial / chemistry
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DNA, Bacterial / metabolism*
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DNA, Bacterial / ultrastructure
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Escherichia coli / chemistry*
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Escherichia coli Proteins / chemistry*
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Escherichia coli Proteins / isolation & purification
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Escherichia coli Proteins / metabolism*
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Escherichia coli Proteins / ultrastructure
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Hydrolysis
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Integrases / metabolism
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Membrane Proteins / chemistry*
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Membrane Proteins / isolation & purification
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Membrane Proteins / metabolism*
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Membrane Proteins / ultrastructure
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Models, Genetic
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Models, Molecular
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Nucleic Acid Conformation
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Pseudomonas aeruginosa / chemistry*
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RNA Helicases / metabolism
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Rec A Recombinases / metabolism
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Recombination, Genetic
Substances
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DNA, Bacterial
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Escherichia coli Proteins
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FtsK protein, E coli
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Membrane Proteins
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Adenosine Triphosphate
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Integrases
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Rec A Recombinases
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DNA Helicases
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RNA Helicases
Associated data
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PDB/2IUS
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PDB/2IUT
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PDB/2IUU