Deletion, insertion or substitution of nucleotides...?

Question

Shown below are the amino acid sequences of the wild-­-type and 4 mutant forms of a polypeptide (the amino acid sequence is taken from the middle of the protein, so
there is no start or stop codon shown). In each mutant, one nucleotide was changed (either a substitution, insertion, or deletion).
Determine the mRNA sequence of the wild-­-type mRNA.

Wild-­-type:
….met-­-his-­-thr-­-leu-­-glu-­-trp-­-v...?
Mutant
#1:
….met-­-his-­-thr-­-leu(stop)
Mutant
#2:
….met-­-his-­-thr-­-pro-­-glu-­-trp-­-v...?
Mutant
#3:
….met-­-arg-­-tyr-­-ser-­-gly-­-val-­-g...?
Mutant
#4:
….ser-­-ile-­-leu-­-trp-­-ser-­-gly(sto...?

Answer 1

DNA sequence:

 

WT: ATG--CAT/CAC--ACT/ACC/ACA/ACG--CTT/CTC/CTA/CTG/TTA/TTG--CAA/CAG--TGG..GTT/GTC/GTG/GTA

 

M1-ATG--CAT/CAC--ACT/ACC/ACA/ACG--CTT/CTC/CTA/CTG/TTA/TTG--TAA/TAG/TGA

 

M2-ATG--CAT/CAC--ACT/ACC/ACA/ACG--CCT/CCA/CCC/CCG--CAA/CAG--TGG..GTT/GTC/GTG/GTA 

 

M3-ATG--CGT/CGC/CGA/CGG/AGA/AGG--TAT/TAC-TCT/TCC/TCA/TCG/AGT/AGC--GGT/GGC/GGA/GGG--GTT/GTC/GTG/GTA--GGT/GGC/GGA/GGG

 

M4-TCT/TCC/TCA/TCG/AGT/AGC--ATT/ATC/ATA--CTT/CTC/CTA/CTG/TTA/TTG--TGG--TCT/TCC/TCA/TCG/AGT/AGC--GGT/GGC/GGA/GGG--TAA/TAG/TGA

 

 Hi Jake,

 

I have provided you with codon sequence to understand how alteration in triplet leads to a different amino acids and insertion of stop codon.

 

For mRNA, substitute uracil or U for T; that is the code for RNA. You can send it to me and I shall check it out for you if you did it right, you can post it here as well and I shall take a look to make sure it is correct.

 

I hope it helps.