Unconventional reading of the glycine codons.
1983; Elsevier BV; Volume: 258; Issue: 21 Linguagem: Inglês
10.1016/s0021-9258(17)44098-1
ISSN1083-351X
AutoresTore Samuelsson, T. Axberg, Thomas Borén, Ulf Lagerkvist,
Tópico(s)Advanced biosensing and bioanalysis techniques
ResumoWe have used a protein-synthesizing in vitro system programmed with the phage message MS2-RNA to investigate the ability of glycyl-tRNAs with different anticodons to read the glycine codons.Under conditions of no competition, when the glycyl-tRNA analyzed was the only source of glycine for protein synthesis, each of the isoacceptors tested, tRNAfIY (anticodon CCC), tRNA2Iy (anticodon N/UCC), (anticodon GCC) from Escherichia coli, and tRNAGIY (anticodon UCC) from Mycoplasma mycoides, could read all of the glycine codons in the MS2 coat protein cistron (GGU, GGC, GGA, and GGG).However, tRNAp'Y seemed to have difficulties reading through the whole cistron.Experiments in which two glycyl-tRNAs competed for the same codon showed that the mycoplasma tRNAGIy (anticodon UCC) was almost as efficient in the unorthodox reading of the codons GGU and GGC as it was in conventional reading.It would seem to be the only tRNAGIY present in Mycoplasma mycoides and our results are consistent with this finding since the mycoplasma tRNAGIY appears to have been designed to read all four glycine codons with approximately equal efficiency.The competition experiments furthermore showed that E. coli (anticodon CCC) reads the codon GGA more efficiently than it reads GGU and GGC suggesting that the mispair C .A between the wobble position of the anticodon and the third codon position might have appreciable stability.
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