Y. Flashner et al., 3 NOVEL PLASMID R6K PROTEINS ACT IN CONCERT TO DISTORT DNA WITHIN THEALPHA-ORIGIN AND BETA-ORIGIN OF DNA-REPLICATION, Molecular microbiology, 19(5), 1996, pp. 985-996
Three novel R6K genes which are responsible for expression of NA disto
rtion polypeptides (DDP) were identified. The DDPs act in vivo in conc
ert to induce similar stepwise DNA helix distortions within two long i
nverted repeats (alpha LIR and beta LIR), which are essential elements
for the two distally located R6K a and beta DNA replication origins.
DDP1 and DDP2 are encoded by two tandem genes located at the 5' end of
alpha LIR, whereas a gene coding for DDP3 is located at the 3' end of
beta LIR. DDP1 and DDP2 are required for primary DNA distortion withi
n alpha LIR or beta LIR, while DDP3 is essential for generation of sec
ondary DNA distortion in these LIR sequences. Creation of DNA distorti
on within alpha LIR depends on its specific interaction with DDP1 and
on the presence of the R6K primase DNA-binding site. The possible rele
vance of these findings to R6K replication is discussed.