Book of Abstracts: Albany 2003
June 17-21 2003
Specific Features of Electrostatic Potential of E.coli Ribosomal Promoters
Electrostatic properties of 4 individual E.coli ribosomal promoters were studied. Using original method, distribution of electrostatic potential around 4 E.coli DNA fragments (500bp) containing 3 different promoters rrnABP1 located at 3939139, 4032828, 4163946 positions and one promoter rrnGP1 located at 2729469 position was calculated.
All promoters are identical in their nucleotide sequences in the region from ?41 to +20bp, 3 promoters rrnABP1 share nucleotide sequence identity in the region from ?70 to +20bp. However, they differ in their functional behavior in response to ADP-ribosylation of a-subunit of RNA polymerase.
Functional response of T4 ?early? promoters to the ADP-ribosylation has recently been shown to be determined by their electrostatic properties and to depend on the presence of some specific elements in electrostatic potential profiles of promoter DNA in far upstream region (1). Therefore, DNA electrostatic potential profiles in the far upstream region of four different ribosomal promoters were analyzed for the presence of such elements. Two ribosomal promoters (rrnABP1-4032828 and rrnGP1-2729469) were shown to have electrostatic pattern identical in design with T4 promoter P164.5 which is inhibited due to ADP-ribosylation of RNA polymerase. Promoter rrnABP1-4163946 has no noticeable specific features in the far upstream region thus indicating that it is not probably affected by the ADP-ribosylation. Promoter rrnABP1-3939139 shares common electrostatic features in the far upstream region with T4 promoter P134.7 which is activated upon the ADP-ribosylation.
So, different E.coli ribosomal promoters possessing identical primary structures differ in their electrostatic properties in the far upstream region. It is most likely that this is the chief cause of their different functional behavior, allowing ribosomal RNA synthesis to be kept at a high level in different conditions.
S. G. Kamzolova1
1Institute of Cell Biophysics of RAS