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-Structure paper
Title | Structural basis of transposon end recognition explains central features of Tn7 transposition systems. |
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Journal, issue, pages | Mol Cell, Vol. 82, Issue 14, Page 2618-22632.e7, Year 2022 |
Publish date | Jul 21, 2022 |
Authors | Zuzanna Kaczmarska / Mariusz Czarnocki-Cieciura / Karolina M Górecka-Minakowska / Robert J Wingo / Justyna Jackiewicz / Weronika Zajko / Jarosław T Poznański / Michał Rawski / Timothy Grant / Joseph E Peters / Marcin Nowotny / |
PubMed Abstract | Tn7 is a bacterial transposon with relatives containing element-encoded CRISPR-Cas systems mediating RNA-guided transposon insertion. Here, we present the 2.7 Å cryoelectron microscopy structure of ...Tn7 is a bacterial transposon with relatives containing element-encoded CRISPR-Cas systems mediating RNA-guided transposon insertion. Here, we present the 2.7 Å cryoelectron microscopy structure of prototypic Tn7 transposase TnsB interacting with the transposon end DNA. When TnsB interacts across repeating binding sites, it adopts a beads-on-a-string architecture, where the DNA-binding and catalytic domains are arranged in a tiled and intertwined fashion. The DNA-binding domains form few base-specific contacts leading to a binding preference that requires multiple weakly conserved sites at the appropriate spacing to achieve DNA sequence specificity. TnsB binding imparts differences in the global structure of the protein-bound DNA ends dictated by the spacing or overlap of binding sites explaining functional differences in the left and right ends of the element. We propose a model of the strand-transfer complex in which the terminal TnsB molecule is rearranged so that its catalytic domain is in a position conducive to transposition. |
External links | Mol Cell / PubMed:35654042 / PubMed Central |
Methods | EM (single particle) / EM (helical sym.) |
Resolution | 2.68 - 3.79 Å |
Structure data | EMDB-13439, PDB-7pik: EMDB-13440: Cryo-EM helical reconstruction of E. coli TnsB in complex with right end fragment of Tn7 transposon |
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Keywords | DNA BINDING PROTEIN / complex / nuclease / Tn7 / transposon |