title: Purification and characterization of a DNA strand transferase from broccoli.
abstract: A protein with DNA binding, renaturation, and strand-transfer activities has been purified to homogeneity from broccoli (Brassica oleracea var italica). The enzyme, broccoli DNA strand transferase, has a native molecular mass of at least 200 kD and an apparent subunit molecular mass of 95 kD and is isolated as a set of isoforms differing only in charge. All three activities are saturated at very low stoichiometry, one monomer per approximately 1000 nucleotides of single-stranded DNA. Strand transfer is not effected by nuclease activity and reannealing, is only slightly dependent on ATP, and is independent of added Mg2+. Transfer requires homologous single- and double-stranded DNA and at higher enzyme concentrations results in very high molecular mass complexes. As with Escherichia coli RecA, transfer by broccoli DNA strand transferase depends strongly on the presence of 3' homologous ends.
authors.affiliation: Department of Biology, Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: A F
authors.initials: AF
authors.lastname: Tissier
authors.forename: M F
authors.initials: MF
authors.lastname: Lopez
authors.forename: E R
authors.initials: ER
authors.lastname: Signer
mesh_terms: D001937:Brassica / Q000201:enzymology*; D002467:Cell Nucleus / Q000201:enzymology*; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D004277:DNA, Single-Stranded / Q000378:metabolism; D029721:Drosophila Proteins; D004591:Electrophoresis, Polyacrylamide Gel; D007700:Kinetics; D008970:Molecular Weight; D009713:Nucleotidyltransferases / Q000302:isolation & purification* / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D004277:DNA, Single-Stranded; D029721:Drosophila Proteins; D009713:Nucleotidyltransferases; C061900:Rrp1 protein, Drosophila