The Mu three-site synapse: a strained assembly platform in which delivery of the L1 transposase binding site triggers catalytic commitment.
The Mu DNA transposition reaction proceeds through a three-site synaptic complex (LER), including the two Mu ends and the transpositional enhancer. We show that the LER contains highly stressed DNA regions in the enhancer and in the L1 transposase binding site. We propose that the L1 site acts as the keystone for assembly of a catalytically competent transpososome. Delivery of L1 through HU-mediated bending completes LER assembly, provides the trigger for necessary conformational transitions in transpososome formation, and allows target capture to occur. Relief of the stress at L1 and the enhancer may help drive Mu A tetramerization and engagement of the Mu ends by the transposase active site.
Kobryn
Kerri
K
Department of Biochemistry, University of Western Ontario, London, Ontario, Canada.
Watson
Mark A
MA
Allison
Ron G
RG
Chaconas
George
G
D010583:Bacteriophage mu / Q000201:enzymology / Q000235:genetics*; D001665:Binding Sites; D002384:Catalysis; D023902:Chromosome Pairing; D004247:DNA / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D018983:DNA Footprinting; D004279:DNA, Viral; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004742:Enhancer Elements, Genetic; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D019895:Transposases / Q000235:genetics / Q000378:metabolism*; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism
D004279:DNA, Viral; D004268:DNA-Binding Proteins; D014764:Viral Proteins; D004247:DNA; D019895:Transposases