... bonds,one from 2¢-OH to the side chain of Asp70, and one from the backbone N of Gly63, and the phosphategroup forming hydrogen bonds from O1 to Arg55, from O2 to the backbone N and the side chain of Thr138, ... E. coli. The probable binding motif for the uracil base is through hydrogen bonds from N3 to the backbone O of Phe133, and from O4to the backbone N and the side chain of Thr131, with the ribose ... and D + F, and (c) electrostatic forces in the central channel of the hexamer between B, C and F, and A, D and E. The hydrophobic interactionsbetween A and B (Fig. 3A,B) are formed between the antiparallel...