Structural analysis of the bipartite DNA-binding domain of Tc3 transposase bound to transposon DNA.
The bipartite DNA-binding domain of Tc3 transposase, Tc3A, was crystallized in complex with its transposon recognition sequence. In the structure the two DNA-binding domains form structurally related helix-turn-helix (HTH) motifs. They both bind to the major groove on a single DNA oligomer, separated by a linker that interacts closely with the minor groove. The structure resembles that of the transcription factor Pax6 DNA-binding domain, but the relative orientation of the HTH-domain is different. The DNA conformation is distorted, characterized by local narrowing of the minor groove and bends at both ends. The protein-DNA recognition takes place through base and backbone contacts, as well as shape-recognition of the distortions in the DNA. Charged interactions are primarily found in the N-terminal domain and the linker indicating that these may form the initial contact area. Two independent dimer interfaces could be relevant for bringing together transposon ends and for binding to a direct repeat site in the transposon end. In contrast to the Tn5 synaptic complex, the two Tc3A DNA-binding domains bind to a single Tc3 transposon end.
Division of Molecular Carcinogenesis, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands.
Stephan
S
Watkins
Gertie
G
van Pouderoyen
Titia K
TK
Sixma
D001483:Base Sequence; D001665:Binding Sites; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D004251:DNA Transposable Elements; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D019281:Dimerization; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D019895:Transposases / Q000737:chemistry* / Q000378:metabolism
D004251:DNA Transposable Elements; D004268:DNA-Binding Proteins; D004247:DNA; D019895:Transposases