On the mechanism of pairing of single- and double-stranded DNA molecules by the recA and single-stranded DNA-binding proteins of Escherichia coli.

摘要: The pairing of single- and double-stranded DNA molecules at homologous sequences promoted by recA single-stranded DNA-binding proteins Escherichia coli follows apparent first-order kinetics. initial rate constant for the reaction are maximal approximately 1 protein/3 protein/8 nucleotides DNA. increases with concentration duplex DNA; however, is independent concentration. Both extent increase linearly increasing length over range 366 to 8623 base pairs. In contrast, size circular between 6,400 10,100 nucleotides. No significant effect on observed when a paired 477 pairs joined lengths heterologous (627-2,367 pairs). Similarly, T7 has no pairing. These findings support mechanism in which protein-single-stranded complex interacts produce an intermediate two aligned sequences. Conversion paranemic joint then occurs rate-determining unimolecular process.