Abstract
Transposition requires a coordinated series of DNA breakage and joining reactions. The Tn7 transposase contains two proteins: TnsA, which carries out DNA breakage at the 5' ends of the transposon, and TnsB, which carries out breakage and joining at the 3' ends of the transposon. TnsB is a member of the retroviral integrase superfamily whose hallmark is a conserved DDE motif. We report here the structure of TnsA at 2.4 A resolution. Surprisingly, the TnsA fold is that of a type II restriction endonuclease. Thus, Tn7 transposition involves a collaboration between polypeptides, one containing a DDE motif and one that does not. This result indicates that the range of biological processes that utilize restriction enzyme-like folds also includes DNA transposition.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Bacterial Proteins / chemistry*
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Bacterial Proteins / genetics
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Bacterial Proteins / metabolism
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Binding Sites
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Catalytic Domain
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Crystallography, X-Ray
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DNA / genetics
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DNA / metabolism*
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DNA Transposable Elements*
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DNA-Binding Proteins / chemistry*
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism
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Deoxyribonucleases, Type II Site-Specific / chemistry*
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Escherichia coli Proteins*
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Magnesium / metabolism
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Models, Molecular
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Mutation
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Protein Folding
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Protein Structure, Secondary
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Recombination, Genetic*
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Structure-Activity Relationship
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Transposases / chemistry*
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Transposases / genetics
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Transposases / metabolism
Substances
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Bacterial Proteins
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DNA Transposable Elements
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DNA-Binding Proteins
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Escherichia coli Proteins
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TnsA protein, E coli
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DNA
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Transposases
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Deoxyribonucleases, Type II Site-Specific
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Magnesium