A comparison between inosine- and guanosine-containing anticodons in ribosome-free codon-anticodon binding

Binding of the ribooligomers, AUC, AUU, AUA, AUCA, AUUA, and AUAA to the isoleucine-accepting tRNAs, tRNA${}_{\mathrm{<mtext>T.\; utilis</mtext>}}{}^{\mathrm{Ile}}$ (anticodon, -IAU-) and tRNA${}_{\mathrm{<mtext>E.\; coli</mtext>}}{}^{\mathrm{Ile}}$ (anticodon, -GAU-) was measured by equilibrium dialysis. With the aid of Scatchard plots, AUCA was shown to bind to one site per tRNA molecule, presumably the anticodon. AUA and AUAA did not measurably attach to either anticodon in the ribosome-free system. All other oligomers were bound to tRNA${}_{\mathrm{<mtext>E.\; coli</mtext>}}{}^{\mathrm{Ile}}$ about 5 to 13 times stronger than to tRNA${}_{\mathrm{<mtext>T.\; utilis</mtext>}}{}^{\mathrm{Ile}}$.