Question

The earliest work on the genetic code established UUU, CCC, and AAA as the codons for Phe, Pro, and Lys, respectively.

Explain the reason why polyG was not used as a translation template in these experiments.

Match the words in the left column to the appropriate blanks in the sentences on the right.

RNA polymerase To establish codons for different amino acids Nirenberg and Matthaei polymerized is physically unstable molecules with the to synthesize polyN, a polyribonucleotide containing only one type of nucleotide residues. When this artificial RNA was placed in a cell-free system containing a bacterial only two extract, ATP, GTP, and the 20 canonical amino acids, the product was a polypeptide containing twenty different amino acid(s). However, polyG and, hence, cannot be used as a only one translation template in vitro ligase NTP forms hairpins is insoluble NMP NDP polynucleotide phosphorylase

Answer 1

To establish codons for different amino acids Nirenberg and Matthaei polymerized twenty different amino acids with the polynucleotide phosphorylase to synthesise polyN, a polyribonucleotide containing only one type of nucleotide residues.

When this artificial RNA was placed in a cell free system containing bacterial extract, ATP, GTP, and the 20 canonical amino acids, the product was a polypeptide containing only one (phenylalanine - Poly U, Proline - Poly C and Lysine - Poly A ) amino acids.

However, polyG forms hairpins which is physically stable and, hence, cannot be used as a translation template invitro.

Poly G folds by itself and form secondary structure and cannot produce a protein. Long Poly G forms highly ordered quadruplex folding which makes it stable. Its coding specificity cannot be determined. So, it is cannot be used as translation template invitro experiments.