There are six forms of a protein; one is normal and five contain different mutat
ID: 191023 • Letter: T
Question
There are six forms of a protein; one is normal and five contain different mutations that change the amino acid at position 150 (called mutants). The normal enzyme has a glutamine residue at amino acid position 150 that is located on the protein surface Here are the 5 mutations: a.glutamine has been replaced by alanine b.glutamine has been replaced by arginine c.glutamine has been replaced by asparagine d.glutamine has been replaced by glutamate e.glutamine has been replaced by phenylalanine 1. Which mutant form of the protein is most like the normal form because it contains the most conservative substitution? 2. Which mutant form has the highest inclination to place amino acid 150 in the interior of the protein?Explanation / Answer
1. The replacement of glutamine with asparagine would cause the least amount of damage to the structural and functional properties of the protein, as both glutamine and asparagine are basic amino acids with an -NH2 R group.Thus, the mutant c, where glutamine has been replaced by asparagine would be most like the normal form.
2. Protein folding takes place in such a way that polar/charged amino acids are placed towards the exterior, near the surface, while non-polar amino acids lie in the interior, so as to allow for solvation and stability. Out of all the mutants, the mutant e, where glutamine has been replaced with phenylalanine would show a tendency to have the amino acid no. 150 in the interior, as phenylalanine is the most non-polar amino acid in the given options.