Describe why no loss of function would occur in the context of a polar or charge
ID: 497743 • Letter: D
Question
Describe why no loss of function would occur in the context of a polar or charged amino acid to alanine.
3. Alanine scanning is a technique to determine the importance ofeach amino acid to the function of the protein. This technique uses site directed mutagenesis to create a seriesof mutants, each ofwhich changes a single amino acid to alanine. If the mutant protein maintains comparable function to the original (wild type) protein, this indicates that the mutated amino acid is not essential. However, ifthe function decreases or is lost, there are several possible effects. For example, certain mutations of the primary structure are so disruptive, the protein is targeted for degradation by the unfolded protein response (UPR) Because the protein is degraded immediately after production, it is not present long enough in the cell to show any function.Explanation / Answer
Alanine is a non-polar, neutral amono acid which is hydrophobic in nature. When a polar or charged amino acid is replaced by alanine then the interactions which hold the protein in place, like H-bonding with water molecules or between the charged amino acid, will be lost. As a result the mutant protein would be expected to show less activity than the non-mutant protein.