. In studying receptor-ligand interactions, the researcher wanted to narrow down

Question

. In studying receptor-ligand interactions, the researcher wanted to narrow down the exact region of interaction between the receptor and the ligand. Amino acids 22 – 27 on the receptor were believed to be involved in ligand binding. So the researcher mutated the following amino acids, one at a time and assayed the effect of these mutations by performing binding assays.

                                             Mutations                                         Binding assays(Receptor-Ligand binding)

                                             Amino acid 23                                                                No

                                             Amino acid 24                                                                Yes

                                             Amino acid 25                                                                No

                                             Amino acid 26                                                                Yes

                                             Amino acid 27                                                                No

From these experiments:

What did the researcher learn from the mutation in amino acid 24?

What did the researcher learn from the mutation in amino acid 27?

Which of the amino acids are involved in receptor-ligand binding? Explain.

Explanation / Answer

A receptor is basically a protein molecule which consists of a unique combination of amino acids that defines a receptor uniquely.

A ligand can be an ion, a molecule made up of atoms or proteins which combines with the receptor to trigger a biochemical process.

This receptor-ligand binding is very specific, as when the target amino acid on the receptor is recognized by the ligand, then only the ligand binds to the receptor. In absence of that specific amino acid, that ligand will not bind to the receptor.

Here in the given question amino acid ( 23-27) were mutated to find whether that amino acid plays the role in binding of the ligand or not. Now, when a mutation is done to the amino acid, it loses its property either due to deletion, addition or substitution of other amino acids due to which ligand does not recognize the receptor thus causing failure in binding with the receptor.

So the basic concept is, despite of mutation, if the ligand is still binding to the receptor then that amino acid is not responsible for binding of the ligand to the receptor. Hence, the result is:

amino acid 24: is not responsible for ligand binding to the receptor as despite of mutation, the ligand is still binding.

amino acid 27: is responsible for ligand binding to the receptor, as mutation caused to aa 27 is not letting ligand bind to the receptor.

amino acid involved in binding are: 23, 25 and 27.

Related Questions

Navigate

• Browse (All)
• Browse #
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.