... determined by the different sizes of the substituents. In the case of TpT, intramolecular stack-ing of thymine residues brings the two C(5)¼C(6)bonds in close proximity, thereby increasing the ... [1]remains disputable. In view of the absolute requirement for Mg2+ in the process of RNA synthesis by E. coli RNAP [19],related primarily to the involvement of Mg2+ in the catalysis of internucleotide ... band doubling for T)11and T+2. Therefore, the measured contribution of theseforms to the integrated intensity of these two bases wasused in the calculation of the contribution of individualbases...