Question

5. The following reaction between fluoroacetamide and thiol usually does not occur as an organic reaction. However, researchers have made it work when they incorporated fluoroacetamide into a protein as a side chain of an unnatural amino acid, which then reacted with a cysteine residue of another protein when these two proteins formed a complex. (a) Explain why the given organic reaction does not work. (b) Explain why fluoroacetamide reacts with cysteine in the protein complex. The direct participation of other amino acid residues in the reaction is negligible

Answer 1

Answer:

Following are the responses to the given points:

Explanation:

In point a:

Its reaction provided is indeed a type of radioactive substitution reaction. Its fluoride group (F group) is a poor leaving group, in which carbon atoms attached to the carbon atom reducing their energy. Thus fluoride group replacement becomes complicated again for the thiol group.

In point b:

When fluoroacetamide is blended with cystine, they associate due to the proximity of ligands, resulting in the formation of a complex of hydrogen bond proteins.