The beta protein of phage lambda binds preferentially to an intermediate in DNA renaturation.
Phage lambda encodes two recombination proteins that are required for homologous recombination in a recA- host strain. Of these two recombination proteins, one is an exonuclease whose action on double-stranded DNA produces 3' single-stranded ends; the other, called beta protein, is a DNA binding protein that promotes the renaturation of complementary single strands. The enzymes of phage lambda provide a model for understanding a recombination pathway called "single-strand annealing". Further investigation of the binding of beta protein to DNA has revealed a new mechanism of renaturation. As reported before, beta protein binds directly to single-stranded DNA, but not to double-stranded DNA. However, in the experiments reported here, we observed that beta protein bound more strongly to a presumed intermediate in the renaturation reaction that beta itself catalyzed, and beta thereby protected all of a renatured duplex 83-mer oligonucleotide from nuclease digestion.
Karakousis
G
G
Department of Genetics, Yale University School of Medicine, New Haven, CT 06510, USA.
Ye
N
N
Li
Z
Z
Chiu
S K
SK
Reddy
G
G
Radding
C M
CM
D010582:Bacteriophage lambda / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D004277:DNA, Single-Stranded / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004279:DNA, Viral / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D009695:Nucleic Acid Renaturation; D009841:Oligonucleotides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D011995:Recombination, Genetic; D014764:Viral Proteins / Q000737:chemistry / Q000378:metabolism*
D004277:DNA, Single-Stranded; D004279:DNA, Viral; D004268:DNA-Binding Proteins; D046911:Macromolecular Substances; D009841:Oligonucleotides; D014764:Viral Proteins