title: Solution conformations of early intermediates in Mos1 transposition.
abstract: DNA transposases facilitate genome rearrangements by moving DNA transposons around and between genomes by a cut-and-paste mechanism. DNA transposition proceeds in an ordered series of nucleoprotein complexes that coordinate pairing and cleavage of the transposon ends and integration of the cleaved ends at a new genomic site. Transposition is initiated by transposase recognition of the inverted repeat sequences marking each transposon end. Using a combination of solution scattering and biochemical techniques, we have determined the solution conformations and stoichiometries of DNA-free Mos1 transposase and of the transposase bound to a single transposon end. We show that Mos1 transposase is an elongated homodimer in the absence of DNA and that the N-terminal 55 residues, containing the first helix-turn-helix motif, are required for dimerization. This arrangement is remarkably different from the compact, crossed architecture of the dimer in the Mos1 paired-end complex (PEC). The transposase remains elongated when bound to a single-transposon end in a pre-cleavage complex, and the DNA is bound predominantly to one transposase monomer. We propose that a conformational change in the single-end complex, involving rotation of one half of the transposase along with binding of a second transposon end, could facilitate PEC assembly.
authors.affiliation: Life Sciences Group, Institut Laue Langevin (ILL), 6 rue Jules Horowitz, 38042 Grenoble, France.
authors.forename: Maxime G
authors.initials: MG
authors.lastname: Cuypers
authors.forename: Maryia
authors.initials: M
authors.lastname: Trubitsyna
authors.forename: Philip
authors.initials: P
authors.lastname: Callow
authors.forename: V Trevor
authors.initials: VT
authors.lastname: Forsyth
authors.forename: Julia M
authors.initials: JM
authors.lastname: Richardson
mesh_terms: D004247:DNA / Q000737:chemistry / Q000378:metabolism; D004251:DNA Transposable Elements; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D019281:Dimerization; D008958:Models, Molecular; D033363:Neutron Diffraction; D017434:Protein Structure, Tertiary; D053838:Scattering, Small Angle; D019895:Transposases / Q000737:chemistry* / Q000378:metabolism; D014961:X-Ray Diffraction
chemical_list: D004251:DNA Transposable Elements; D004268:DNA-Binding Proteins; C111652:mariner transposases; D004247:DNA; D019895:Transposases