Give the amino acid sequence predicted by the following nucl

Give the amino acid sequence predicted by the following nucleotide sequence of an RNA molecule. (Hint – look for the first start codon.)

5’ – CCAUGCAGCGACCGU(G*)GGAAGGUCUUA – 3’

Question 1: If the G-residue in parentheses and indicated by the asterisk mutated to an A nucleotide, what would the predicted amino acid sequence be?

Question 2: If the G-residue in parentheses and indicated by the asterisk was deleted, what would the predicted amino acid sequence be?

PLEASE ANSWER BOTH QUESTION 1 AND 2!!!! Please explain thoroughly!! Thanks

Solution

Starting from the start codon 5\' AUG 3\', the translation of the mRNA will code the following amino acids without mutation.

5’ – CC AUG CAG CGA CCG U(G*)G GAA GGU CUU A – 3’

Met - Gln - Arg - Pro - Trp - Glu - Gly - Leu

Question 1:

If the G-residue in parentheses and indicated by the asterisk mutated to an A nucleotide, the mutated RNA will look like:

5’ – CC AUG CAG CGA CCG U(A)G GAA GGU CUU A – 3’

And the amino acid coded by this mutated RNA will be:

Met - Gln - Arg - Pro

There will be no addition of amino acid after proline as UAG codes for stop codon. So the process of translation will stop here.

Question 2:

If the G-residue in parentheses and indicated by the asterisk was deleted, the mutated RNA will look like:

5’ – CC AUG CAG CGA CCG UGG AAG GUC UUA – 3’

Met - Gln - Arg - Pro - Trp - Lys - Val - Leu

The mutated amino acid will have different amino acid sequence than the unmutated amino acid, due to frame shift mutation.