The effect of specific structural modification on the biological activity of E. coli arginine tRNA.

Escherichia coli arginine tRNA1 has been modified at position s2C32 with iodoacetamide and a spin labelled derivative. The small effects on the charging ability of tRNA by the modifiications suggest that the synthetase does not bind to the tRNA in this region of the anticodon loop before the anticodon. A ternary complex of elongation factor Tu, GTP and the modified Arg-tRNA, can be formed allowing future studies of enzymatic binding to the ribosome. Using the triplet binding assay the native Arg-tRNA1 decodes all 4 codons beginning with CG. The modified Arg-tRNA1 has a restricted decoding but the decoding pattern is still unusual according to the Wobble Hypothesis.