Investigation of the Binding of Escherichia coli RNA Polymerase to DNA from Bacteriophages T2 and T7 by Kinetic Formaldehyde Method and Electron Microscopy

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Abstract
The complexes of T2 DNA with RNA polymerase of E. coli were studied by 2 methods: kinetic formaldehyde method with preliminary fixation of complexes with low formaldehyde concentrations and EM. For EM investigations the effect of different conditions of formaldehyde fixation for DNA.cntdot.RNA-polymerase complexes was studied and optimal fixation conditions were found. The suggested fixation method for DNA.cntdot.RNA-polymerase complexes allows investigation of RNA polymerase molecule distribution on DNA in a wide range of conditions (ionic strength of the solution, weight ratio of enzyme to DNA, etc.). The comparison of the concentration of RNA polymerase molecules bound to DNA, determined by EM, and the concentration of defects in DNA, as determined by the kinetic formaldehyde method, showed their coincidence. The EM procedure was used to make maps of RNA polymerase distribution on T7 DNA. A correlation between the binding regions of the enzyme and the genetic map of early DNA T7 region was found.