Question

Because of the possibility of ‘wobble’ in the base-pair made between the third (5’) position of the anticodon and the third (3’) base of the the mRNA codon , single tRNAs with appropriate bases in this position are often employed by the cell to decode more than one codon specifying the same amino acid (synonymous codons). This is not possible and does not occur in the first or second positions of the codon.

N1-methyl-pseudouridine has been used to replace uracil in the preparation of mRNA for vaccines because it renders the mRNA less immunogenic. It has the same potential for base–pairing as uracil, so that even if its orientation in space is not absolutely identical, one would expect it to be able to form a base-pair with the wobble position of the appropriate anticodon.

But what is the situation with N1-methyl-pseudouridine at the first or second codon positions, where base-pairing is more stringent? Is there a potential for miscoding there, producing a proteins with incorrect amino acids?

Answer 1

The wobble phenomenon allows for flexibility in decoding synonymous codons with single tRNAs. N1-methyl-pseudouridine can replace uracil at the wobble position, maintaining accurate decoding. However, potential miscoding can occur at the first and second positions of the codon.

Step-by-step explanation:

The wobble phenomenon in codon-anticodon interactions allows for flexibility in base pairing and enables single tRNAs to decode multiple codons for the same amino acid.

N1-methyl-pseudouridine can replace uracil in mRNA and form base pairs at the wobble position, ensuring accurate decoding of synonymous codons for the respective amino acid. However, at the first and second positions of the codon, where base pairing is more stringent, there is a potential for miscoding if N1-methyl-pseudouridine is present.