Recombination proficiency and Chi activity of the <i>P. syringae</i> RecBCD enzymes.

aThe enzyme alleles were expressed from plasmid-borne genes, except in V66 strain that had wild-type recBCD alleles on chromosome. The mutant enzyme alleles (recBK28QCD, recBD1118ACD, and recBCDK229Q) were all derivatives of the P. syringae enzyme (recBCDPs). bThe recombination frequency values are based on three independent crossings between the recipient V67 containing the plasmid-borne recBCD alleles and donor strain V1306 (Hfr PO44). The standard error of means (± SEM) have been indicated. cThe frequency of J+R+ recombinants in each set of crosses (Cross 1: phage 1081×1082, and Cross 2: phage 1083×1084) was determined as described under Materials and Methods. dData are the mean ± SEM from three independent experiments.