The amino-acid sequence shown in the following table was obtained from the central region of a particular polypeptide chain in the wild-type and several mutant bacterial strains: Codon 1 2 3 4 5 6 7 8 9
a. Wild-type: Phe Leu Pro Thr Val Thr Thr Arg Trp
b. Mutant 1: Phe Leu His His Gly Asp Asp Thr Val
c. Mutant 2: Phe Leu Pro Thr Met Thr Thr Arg Trp
d. Mutant 3: Phe Leu Pro Thr Val Thr Thr Arg
e. Mutant 4: Phe Pro Pro Arg
f. Mutant 5: Phe Leu Pro Ser Val Thr Thr Arg Trp
Each mutant represents a single nucleotide change from the original wild-type gene. For each mutant, explain what SINGLE nucleotide mutation at the DNA level accounts for the change(s) in amino acid sequence. Also, state in which codon and which position the mutation took place and then fully characterize the mutation as a base-pair substitution mutation (transversion or transition; and missense, nonsense, etc.) or a frameshift mutation. Finally, recreate as much of the original wild-type mRNA sequence as possible.
The amino-acid sequence shown in the following table was obtained from the central region of a particular polypeptide chain in the wild-type and several mutant bacterial strains: Codon 1 2 3 4 5 6 7 8 9
a. Wild-type: Phe Leu Pro Thr Val Thr Thr Arg Trp
b. Mutant 1: Phe Leu His His Gly Asp Asp Thr Val
c. Mutant 2: Phe Leu Pro Thr Met Thr Thr Arg Trp
d. Mutant 3: Phe Leu Pro Thr Val Thr Thr Arg
e. Mutant 4: Phe Pro Pro Arg
f. Mutant 5: Phe Leu Pro Ser Val Thr Thr Arg Trp
Each mutant represents a single nucleotide change from the original wild-type gene. For each mutant, explain what SINGLE nucleotide mutation at the DNA level accounts for the change(s) in amino acid sequence. Also, state in which codon and which position the mutation took place and then fully characterize the mutation as a base-pair substitution mutation (transversion or transition; and missense, nonsense, etc.) or a frameshift mutation. Finally, recreate as much of the original wild-type mRNA sequence as possible.
