[The effect of the phage lambda ral gene on the level of synthesis of the EcoK restriction endonuclease beta-subunit].

E. coli hsd genes were subcloned from lambda 642 (ral+) into lambda L47.1 vector (ral-after replacement). The influence of bacteriophage lambda ral gene on the expression efficiency of hsdS kappa, hsdM kappa genes was investigated. It was shown, that its presence in vitro enhanced the synthesis of beta-subunit, hsdM gene product, and the increase of modification in vivo was observed. It is proposed that the increase of modification rate of lambda phage fully unmodified DNA is connected with the appearance of E. coli DNA methylase consisting of beta- and gamma-subunits but lacking alpha-subunit.