Mu transpositional recombination: donor DNA cleavage and strand transfer in trans by the Mu transposase.
Central to the Mu transpositional recombination are the two chemical steps; donor DNA cleavage and strand transfer. These reactions occur within the Mu transpososome that contains two Mu DNA end segments bound to a tetramer of MuA, the transposase. To investigate which MuA monomer catalyzes which chemical reaction, we made transpososomes containing wild-type and active site mutant MuA. By pre-loading the MuA variants onto Mu end DNA fragments of different length prior to transpososome assembly, we could track the catalysis by MuA bound to each Mu end segment. The donor DNA end that underwent the chemical reaction was identified. Both the donor DNA cleavage and strand transfer were catalyzed in trans by the MuA monomers bound to the partner Mu end. This arrangement explains why the transpososome assembly is a prerequisite for the chemical steps.
Savilahti
H
H
Laboratory of Molecular Biology, National Institute of Diabetes, and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
Mizuuchi
K
K
D000595:Amino Acid Sequence; D010583:Bacteriophage mu / Q000235:genetics*; D001665:Binding Sites / Q000502:physiology; D004247:DNA / Q000378:metabolism; D004249:DNA Damage / Q000502:physiology; D004254:DNA Nucleotidyltransferases / Q000235:genetics* / Q000378:metabolism; D004279:DNA, Viral / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000378:metabolism; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D011995:Recombination, Genetic / Q000502:physiology*; D019895:Transposases
D004279:DNA, Viral; D004268:DNA-Binding Proteins; D004247:DNA; D004254:DNA Nucleotidyltransferases; D019895:Transposases