Question

In studies of the amino acid sequence of wild-type and mutant forms of tryptophan synthetase in \(E .\) coli, the following changes have been observed: Determine a set of triplet codes in which only a single-nucleotide change produces each amino acid change.

Short answer

Answer: One possible set of triplet codes for each amino acid change is: 1. Arginine (Arg) to Histidine (His): CGU -> CAU 2. Asparagine (Asn) to Aspartic acid (Asp): AAU -> GAU 3. Phenylalanine (Phe) to Leucine (Leu): UUU -> UUA 4. Serine (Ser) to Proline (Pro): UCU -> CCU

Step-by-step solution

List the amino acid changes

Write down the amino acid changes given in the problem: 1. Arginine (Arg) to Histidine (His) 2. Asparagine (Asn) to Aspartic acid (Asp) 3. Phenylalanine (Phe) to Leucine (Leu) 4. Serine (Ser) to Proline (Pro)

Determine corresponding codons in the genetic code

Identify the codons for the amino acids involved in the changes using the genetic code table: 1. Arginine (Arg): CGU, CGC, CGA, CGG, AGA, AGG Histidine (His): CAU, CAC 2. Asparagine (Asn): AAU, AAC Aspartic acid (Asp): GAU, GAC 3. Phenylalanine (Phe): UUU, UUC Leucine (Leu): UUA, UUG, CUU, CUC, CUA, CUG 4. Serine (Ser): UCU, UCC, UCA, UCG, AGU, AGC Proline (Pro): CCU, CCC, CCA, CCG

Find single-nucleotide changes matching amino acid changes

Compare codons of the original and mutated amino acids to find possible single-nucleotide changes: 1. Arginine (Arg) to Histidine (His): CGU -> CAU 2. Asparagine (Asn) to Aspartic acid (Asp): AAU -> GAU 3. Phenylalanine (Phe) to Leucine (Leu): UUU -> UUA 4. Serine (Ser) to Proline (Pro): UCU -> CCU Note that there might be more than one possible set of triplet codes that satisfy the given conditions. However, we have found one set of triplet codes that require only a single-nucleotide change for each amino acid change as mentioned in the problem statement.

Final Answer

The set of triplet codes in which only a single-nucleotide change produces each amino acid change is: 1. Arginine (Arg) to Histidine (His): CGU -> CAU 2. Asparagine (Asn) to Aspartic acid (Asp): AAU -> GAU 3. Phenylalanine (Phe) to Leucine (Leu): UUU -> UUA 4. Serine (Ser) to Proline (Pro): UCU -> CCU