Transposases are needed for efficient transposition of the insertion sequence or transposon DNA. This family includes transposases for IS200 from E. coli.
Transposases are needed for efficient transposition of the insertion sequence or transposon DNA. This entry represents a domain found in transposases for IS200 from Escherichia coli [ (PUBMED:10471738) ].
Active site sharing and subterminal hairpin recognition in a new class of DNAtransposases.
Mol Cell. 2005; 20: 143-54
Display abstract
Many bacteria harbor simple transposable elements termed insertion sequences(IS). In Helicobacter pylori, the chimeric IS605 family elements are particularlyinteresting due to their proximity to genes encoding gastric epithelial invasion factors. Protein sequences of IS605 transposases do not bear the hallmarks ofother well-characterized transposases. We have solved the crystal structure offull-length transposase (TnpA) of a representative member, ISHp608. Structurally,TnpA does not resemble any characterized transposase; rather, it is related torolling circle replication (RCR) proteins. Consistent with RCR, Mg2+ and aconserved tyrosine, Tyr127, are essential for DNA nicking and the formation of a covalent intermediate between TnpA and DNA. TnpA is dimeric, contains two shared active sites, and binds two DNA stem loops representing the conserved invertedrepeats near each end of ISHp608. The cocrystal structure with stem-loop DNAillustrates how this family of transposases specifically recognizes and pairsends, necessary steps during transposition.
