The development of new drugs is the primary way in which researchers continue to advance the fight against diseases such as cancer, Alzheimer’s, and cystic fibrosis. The process of developing new drugs is a complicated endeavor. Before drug trials can begin, researchers must learn the nature of the drug in question and how the human body processes its effects.

Two of the most important steps in this process are biological target identification and validation. More simply put, researchers must find a protein that will accept the molecular structure of the drug and enable the body to utilize it. This involves a series of procedures designed to isolate a drug target and measure its effectiveness.

What Is a Drug Target?

A drug target is a molecule in the human body that is closely tied to the disease process and whose molecular interaction with a drug could produce a beneficial effect. For example, beta-blockers interact with a drug target site whose function is to bind to the hormone epinephrine. Beta-blockers binding effectively blocks epinephrine’s effects on the system, causing the heart to beat slower and less forcefully.

Most drug targets are proteins, although RNA and genes may also serve as targets. Researchers must perform analysis on the potential drug targets to identify the types of drug molecules that will interact with the target in the appropriate way, eliciting the desired response.

Understanding Binding Sites

Since drugs usually act on the human body by engaging with a molecular target, it is important to find the perfect target for any drug under development. Usually, this means intensive research into the potential protein binding sites that may allow molecular interaction. What, exactly, is a binding site?

A binding site is an area on the outside of the protein molecule that can bind to a molecule, such as a messenger, hormone, or another modulator. Upon binding, the reaction between the protein and the binding partner – known as a ligand – usually changes the protein’s shape, altering its function. For many diseases, altering the protein’s function in a particular way can remedy issues related to that function.

Ligands and Their Importance

In most cases, protein binding sites will only allow bonds with specific ligands. Ligands that are not the correct shape or molecular structure will not bind adequately with the binding site. Conversely, the proper ligand will fit properly, allowing the formation of the strong hydrogen bonds that are necessary to keep it in place.

Once the ligand is in place, the hydrophobic atoms of the protein molecule shift into place, surrounding the ligand. This ensures limited reactions from the surrounding environment and provides the ligand with a more secure fit. Drugs that closely mirror the structure of a particular ligand can fit into their place and thus have their own effects on protein function.

Target Identification and Validation are Crucial to Drug Development

To develop a drug that can have a therapeutic effect on the body, researchers must identify and validate the ideal binding sites the drug could utilize. For these reasons, it is essential to research all possible target sites and study the molecular interactions between drug ligands and the protein itself. Then, drug ligands that adequately bind to each target can proceed in development, potentially resulting in a drug that produces relief for those suffering from disease.