Comparative analysis of electrostatic potential distribution for ?early? T4 phage promoters was undertaken, along with calculation of topography of electrostatic potential around the native and ADP-ribosylated C-terminal domain of RNA polymerase α-subunit. The data obtained indicate that there is specific difference in the patterns of electrostatic potential distribution in far upstream regions of T4 promoters differing by their response to ADP-ribosylation of RNA polymerase. A specific change in profiles of electrostatic potential distribution for the native and ADP-ribosylated forms of RNA polymerase α-subunit was observed suggesting that this factor may be responsible for modulating T4 promoter activities in response to the enzyme modification.