Lysozyme is an enzyme that breaks down bacterial cell walls and is found in your tears, mucus, and saliva. A mutation occurs in the gene for lysozyme that results in a lysine (a positively charged amino acid) being substituted for an arginine (also a positively charged amino acid). Do you think that the mutant lysozyme will function similarly to the normal lysozyme?
A) no, because all changes in protein primary sequence result in functional differences
B) no, because changing lysine to arginine will cause the protein to denature
C) yes, because both lysine and arginine are positively charged so the tertiary structure and therefore function should be similar
D) yes, because protein function stays the same no matter what mutations occur

Question

Quizplus · Accepted Answer

Both lysine and arginine are positively charged amino acids, so the substitution is not likely to affect the overall charge distribution of the protein or its tertiary structure significantly. Moreover, the function of lysozyme relies on its ability to interact with bacterial cell wall components, and this interaction is not likely to be affected by a single amino acid substitution. Therefore, the mutant lysozyme should function similarly to the normal lysozyme.

Lysozyme Is an Enzyme That Breaks Down Bacterial Cell Walls