Base flipping in Tn10 transposition: an active flip and capture mechanism

The bacterial Tn5 and Tn10 transposases have a single active site that cuts both strands of DNA at their respective transposon ends. This is achieved using a hairpin intermediate that requires the DNA to change conformation during the reaction. In Tn5 these changes are controlled in part by a flippe...

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Main Authors: Bischerour, Julien, Chalmers, Ronald
Format: Article
Published: Public Library of Science 2009
Online Access:https://eprints.nottingham.ac.uk/2772/
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author Bischerour, Julien
Chalmers, Ronald
author_facet Bischerour, Julien
Chalmers, Ronald
author_sort Bischerour, Julien
building Nottingham Research Data Repository
collection Online Access
description The bacterial Tn5 and Tn10 transposases have a single active site that cuts both strands of DNA at their respective transposon ends. This is achieved using a hairpin intermediate that requires the DNA to change conformation during the reaction. In Tn5 these changes are controlled in part by a flipped nucleoside that is stacked on a tryptophan residue in a hydrophobic pocket of the transposase. Here we have investigated the base flipping mechanism in Tn10 transposition. As in Tn5 transposition, we find that base flipping takes place after the first nick and is required for efficient hairpin formation and resolution. Experiments with an abasic substrate show that the role of base flipping in hairpin formation is to remove the base from the DNA helix. Specific interactions between the flipped base and the stacking tryptophan residue are required for hairpin resolution later in the reaction. We show that base flipping in Tn10 transposition is not a passive reaction in which a spontaneously flipped base is captured and retained by the protein. Rather, it is driven in part by a methionine probe residue that helps to force the flipped base from the base stack. Overall, it appears that base flipping in Tn10 transposition is similar to that in Tn5 transposition.
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spelling nottingham-27722020-05-04T16:28:30Z https://eprints.nottingham.ac.uk/2772/ Base flipping in Tn10 transposition: an active flip and capture mechanism Bischerour, Julien Chalmers, Ronald The bacterial Tn5 and Tn10 transposases have a single active site that cuts both strands of DNA at their respective transposon ends. This is achieved using a hairpin intermediate that requires the DNA to change conformation during the reaction. In Tn5 these changes are controlled in part by a flipped nucleoside that is stacked on a tryptophan residue in a hydrophobic pocket of the transposase. Here we have investigated the base flipping mechanism in Tn10 transposition. As in Tn5 transposition, we find that base flipping takes place after the first nick and is required for efficient hairpin formation and resolution. Experiments with an abasic substrate show that the role of base flipping in hairpin formation is to remove the base from the DNA helix. Specific interactions between the flipped base and the stacking tryptophan residue are required for hairpin resolution later in the reaction. We show that base flipping in Tn10 transposition is not a passive reaction in which a spontaneously flipped base is captured and retained by the protein. Rather, it is driven in part by a methionine probe residue that helps to force the flipped base from the base stack. Overall, it appears that base flipping in Tn10 transposition is similar to that in Tn5 transposition. Public Library of Science 2009-07-10 Article PeerReviewed Bischerour, Julien and Chalmers, Ronald (2009) Base flipping in Tn10 transposition: an active flip and capture mechanism. PLoS ONE, 4 (7). e6201/1-e6201/8. ISSN 1932-6203 http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0006201 doi:10.1371/journal.pone.0006201 doi:10.1371/journal.pone.0006201
spellingShingle Bischerour, Julien
Chalmers, Ronald
Base flipping in Tn10 transposition: an active flip and capture mechanism
title Base flipping in Tn10 transposition: an active flip and capture mechanism
title_full Base flipping in Tn10 transposition: an active flip and capture mechanism
title_fullStr Base flipping in Tn10 transposition: an active flip and capture mechanism
title_full_unstemmed Base flipping in Tn10 transposition: an active flip and capture mechanism
title_short Base flipping in Tn10 transposition: an active flip and capture mechanism
title_sort base flipping in tn10 transposition: an active flip and capture mechanism
url https://eprints.nottingham.ac.uk/2772/
https://eprints.nottingham.ac.uk/2772/
https://eprints.nottingham.ac.uk/2772/