title: Mechanism of Mos1 transposition: insights from structural analysis.
abstract: We present the crystal structure of the catalytic domain of Mos1 transposase, a member of the Tc1/mariner family of transposases. The structure comprises an RNase H-like core, bringing together an aspartic acid triad to form the active site, capped by N- and C-terminal alpha-helices. We have solved structures with either one Mg2+ or two Mn2+ ions in the active site, consistent with a two-metal mechanism for catalysis. The lack of hairpin-stabilizing structural motifs is consistent with the absence of a hairpin intermediate in Mos1 excision. We have built a model for the DNA-binding domain of Mos1 transposase, based on the structure of the bipartite DNA-binding domain of Tc3 transposase. Combining this with the crystal structure of the catalytic domain provides a model for the paired-end complex formed between a dimer of Mos1 transposase and inverted repeat DNA. The implications for the mechanisms of first and second strand cleavage are discussed.
authors.affiliation: School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
authors.forename: Julia M
authors.initials: JM
authors.lastname: Richardson
authors.forename: Angela
authors.initials: A
authors.lastname: Dawson
authors.forename: Natasha
authors.initials: N
authors.lastname: O'Hagan
authors.forename: Paul
authors.initials: P
authors.lastname: Taylor
authors.forename: David J
authors.initials: DJ
authors.lastname: Finnegan
authors.forename: Malcolm D
authors.initials: MD
authors.lastname: Walkinshaw
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D004251:DNA Transposable Elements; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D019281:Dimerization; D004330:Drosophila / Q000201:enzymology; D008345:Manganese; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010957:Plasmids; D011487:Protein Conformation; D017510:Protein Folding; D017386:Sequence Homology, Amino Acid; D021241:Spectrometry, Mass, Electrospray Ionization; D019895:Transposases
chemical_list: D004251:DNA Transposable Elements; D004268:DNA-Binding Proteins; C111652:mariner transposases; D008345:Manganese; D019895:Transposases