8AA5

Cryo-EM structure of the strand transfer complex of the TnsB transposase (type V-K CRISPR-associated transposon)

This is a non-PDB format compatible entry.

Summary for 8AA5

• Entry DOI: 10.2210/pdb8aa5/pdb
• EMDB information: 15294
• Descriptor: TnsB, RE_Target, RE_PolyA, ... (8 entities in total)
• Functional Keywords: transposase, complex, crispr, transposition, dna cleavage, ligation, dna binding protein
• Biological source: Scytonema hofmannii; More
• Total number of polymer chains: 10
• Total formula weight: 376637.76

Authors

Tenjo-Castano, F.,Sofos, N.,Lopez-Mendez, B.,Stutzke, L.S.,Fuglsang, A.,Stella, S.,Montoya, G. (deposition date: 2022-06-30, release date: 2022-10-19, Last modification date: 2024-07-24)

Primary citation

Tenjo-Castano, F.,Sofos, N.,Lopez-Mendez, B.,Stutzke, L.S.,Fuglsang, A.,Stella, S.,Montoya, G.
Structure of the TnsB transposase-DNA complex of type V-K CRISPR-associated transposon.
Nat Commun, 13:5792-5792, 2022

PubMed Abstract: CRISPR-associated transposons (CASTs) are mobile genetic elements that co-opted CRISPR-Cas systems for RNA-guided transposition. Here we present the 2.4 Å cryo-EM structure of the Scytonema hofmannii (sh) TnsB transposase from Type V-K CAST, bound to the strand transfer DNA. The strand transfer complex displays an intertwined pseudo-symmetrical architecture. Two protomers involved in strand transfer display a catalytically competent active site composed by DDE residues, while other two, which play a key structural role, show active sites where the catalytic residues are not properly positioned for phosphodiester hydrolysis. Transposon end recognition is accomplished by the NTD1/2 helical domains. A singular in trans association of NTD1 domains of the catalytically competent subunits with the inactive DDE domains reinforces the assembly. Collectively, the structural features suggest that catalysis is coupled to protein-DNA assembly to secure proper DNA integration. DNA binding residue mutants reveal that lack of specificity decreases activity, but it could increase transposition in some cases. Our structure sheds light on the strand transfer reaction of DDE transposases and offers new insights into CAST transposition.

PubMed: 36184667
DOI: 10.1038/s41467-022-33504-5

Experimental method

ELECTRON MICROSCOPY (2.46 Å)