Mechanism of IS200/IS605 Family DNA Transposases: Activation and Transposon-Directed Target Site Selection

Orsolya Barabas, Donald R. Ronning, Catherine Guynet, Alison Burgess Hickman, Bao Ton-Hoang, Michael Chandler, Fred Dyda

Research output: Contribution to journalArticlepeer-review

77 Scopus citations

Abstract

The smallest known DNA transposases are those from the IS200/IS605 family. Here we show how the interplay of protein and DNA activates TnpA, the Helicobacter pylori IS608 transposase, for catalysis. First, transposon end binding causes a conformational change that aligns catalytically important protein residues within the active site. Subsequent precise cleavage at the left and right ends, the steps that liberate the transposon from its donor site, does not involve a site-specific DNA-binding domain. Rather, cleavage site recognition occurs by complementary base pairing with a TnpA-bound subterminal transposon DNA segment. Thus, the enzyme active site is constructed from elements of both protein and DNA, reminiscent of the interdependence of protein and RNA in the ribosome. Our structural results explain why the transposon ends are asymmetric and how the transposon selects a target site for integration, and they allow us to propose a molecular model for the entire transposition reaction.

Original languageEnglish (US)
Pages (from-to)208-220
Number of pages13
JournalCell
Volume132
Issue number2
DOIs
StatePublished - Jan 25 2008

Keywords

  • DNA

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

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