Principles of Biochemistry, Volume 3 - A. Lehninger 1985

Molecular Mechanisms of Genetic Information Transfer
Protein Synthesis and Its Regulation
tRNA acts as an adaptor

Once attached to its corresponding tRNA, The amino acid no longer plays a role in determining the Specificity of the aminoacyl-tRNA, since the aminoacyl group itself is recognized neither by the ribosome nor by the mRNA. The specificity of aminoacyl-tRNA is determined solely by the tRNA Structure. This was definitively proven by elegant experiments in which enzymatic Methods were used to produce cysteinyl-tRNACys, which was then isolated and chemically converted into alanyl-tRNACys. When this hybrid aminoacyl-tRNA—carrying Alanine but containing the anticodon for Cysteine—was incubated in a Cell-free protein-synthesizing system, Analysis of the newly synthesized polypeptide revealed that alanine was incorporated at the positions normally occupied by cysteine. Thus, this experiment provided conclusive proof of Crick's adaptor hypothesis.



Last update: 06/08/2026

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