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Updated: Jul 31, 2026

Preparation of the Mgm101 Recombination Protein by MBP-based Tagging Strategy
Published on: June 25, 2013
Unexpected structural diversity in DNA recombination: the restriction endonuclease connection
A B Hickman1, Y Li, S V Mathew
1Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA. ahickman@helix.nih.gov
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.
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