KINETICS OF ALTERATION AND MODIFICATION OF DNA-DEPENDENT RNA-POLYMERASE IN T4-INFECTED E COLI CELLS

The decrease in the activity of DNA‐dependent RNA polymerase in Escherichia coli after infection with bacteriophage T4 is the consequence of a structural change of the polymerase and not of the appearance of an inhibitor. The kinetics of this change were followed using polymerases highly purified at different times after infection (a) by measuring the specific enzymatic activity with T4‐ and calf thymus DNA as templates and (b) by following the appearance of the modified polymerase‐subunit in disc‐electrophoresis. The results allow one to differentiate between two consecutive processes: A very rapid alteration which inactivates the RNA polymerase for T4‐DNA, but not for other DNA templates, and which does not require protein synthesis. A structural modification which depends on protein synthesis and leads to a change in one subunit of the polymerase. As shown by the use of the T4‐mutants am BL 292 and am N.134 neither gene 55 nor gene 33, both involved in the transcription of late genes, are participating in the modification reaction. Copyright © 1969, Wiley Blackwell. All rights reserved