6XGX

ISCth4 transposase, strand transfer complex 1, STC1

Summary for 6XGX

• Entry DOI: 10.2210/pdb6xgx/pdb
• Descriptor: Mutator family transposase, DNA (47-MER), DNA (25-MER), ... (4 entities in total)
• Functional Keywords: antibiotic resistance, promoter, transposon, recombination
• Biological source: Hungateiclostridium thermocellum (strain ATCC 27405 / DSM 1237 / JCM 9322 / NBRC 103400 / NCIMB 10682 / NRRL B-4536 / VPI 7372); More
• Total number of polymer chains: 5
• Total formula weight: 123563.40

Authors

Kosek, D.,Dyda, F. (deposition date: 2020-06-18, release date: 2020-10-14, Last modification date: 2023-10-18)

Primary citation

Kosek, D.,Hickman, A.B.,Ghirlando, R.,He, S.,Dyda, F.
Structures of ISCth4 transpososomes reveal the role of asymmetry in copy-out/paste-in DNA transposition.
Embo J., 40:e105666-e105666, 2021

PubMed Abstract: Copy-out/paste-in transposition is a major bacterial DNA mobility pathway. It contributes significantly to the emergence of antibiotic resistance, often by upregulating expression of downstream genes upon integration. Unlike other transposition pathways, it requires both asymmetric and symmetric strand transfer steps. Here, we report the first structural study of a copy-out/paste-in transposase and demonstrate its ability to catalyze all pathway steps in vitro. X-ray structures of ISCth4 transposase, a member of the IS256 family of insertion sequences, bound to DNA substrates corresponding to three sequential steps in the reaction reveal an unusual asymmetric dimeric transpososome. During transposition, an array of N-terminal domains binds a single transposon end while the catalytic domain moves to accommodate the varying substrates. These conformational changes control the path of DNA flanking the transposon end and the generation of DNA-binding sites. Our results explain the asymmetric outcome of the initial strand transfer and show how DNA binding is modulated by the asymmetric transposase to allow the capture of a second transposon end and to integrate a circular intermediate.

PubMed: 33006208
DOI: 10.15252/embj.2020105666

Experimental method

X-RAY DIFFRACTION (3.5 Å)