Year: 2026
Type: article
Abstract: (Tn7)-like transposons typically contain asymmetric left- and right-end sequences that flank and define DNA cargo. However, how the transposase recognizes these different sequences and assembles them into a catalytically competent state for cut-and-paste transposition remains unknown. Here, we present the cryo-electron microscopy structure of the VchCAST transposase TnsB in complex with transposon DNA ends and host factor IHF, along with biochemistry, molecular dynamics, and in vivo analyses. Our structure reveals the stoichiometry and architecture of the assembly, as well as the DNA distortions required to accommodate transposon end asymmetry. Molecular dynamics suggests that these distortions are required for the coordinated assembly of the complex. Physical association of asymmetric left and right ends results in a previously uncharacterized protein-protein interface that is required for transposition efficiency. Our findings explain how transposases regulate the pairing of transposon end sequences for high-fidelity recognition, reveal a model of transposon-end synapsis, and suggest future avenues to engineer DNA cargo for genome-editing applications.
Source: Science Advances
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $4,500
Funders: National Science Foundation, Alfred P. Sloan Foundation, Cystic Fibrosis Foundation, Camille and Henry Dreyfus Foundation, St. Jude Children's Research Hospital, American Lebanese Syrian Associated Charities, National Institutes of Health, National Institute of General Medical Sciences, Office of Advanced Cyberinfrastructure, Division of Chemistry
Awards: G1453181110, G1555197637, G1732709109, G1787346651, Track 4: Advanced CI Coordination Ecosystem: Monitoring and Measurement Services, G338811424, G34258105, G3562386289, Track 1: ACCESS Resource Allocations Marketplace and Platform Services (RAMPS), G4010157413, G4090037298, G4275568664, G4500179846, ACO: An Open CI Ecosystem to Advance Scientific Discovery (OpenCI), G4736717341, G4773471377, Track 3: COre National Ecosystem for CyberinfrasTructure (CONECT), G5097243881, G5156331529, G5367127336, G5464919783, G560129009, G63540804, G6997014837, G7395639013, G7526614437, G7916508619, G806035767, Track 2: Customized Multi-tier Assistance, Training, and Computational Help (MATCH) for End User ACCESS to CI, CAREER: Mechanistic Investigations of Conformational Activation and Catalysis in Emerging CRISPR-Cas Systems, G8499740153, G885392968, G8994211811, Investigating the metal-dependent function, allostery and inhibition of CRISPR-Cas9, Structural Basis of Programmable DNA-Insertion via Cryo-EM Studies of CRISPR-Associated TnsC, Structural and evolutionary basis for insertion unidirectionality in RNA-guided DNA transposition systems
OpenAlex ID: W7216325154