# Computer-aided drug design

During the process of developing a new drug against a certain disease or against a specific type of pain (e.g. headache), scientists first try to find a so-called target molecule in the human body. This target molecule plays an important role in the causation or the progress of the disease or the pain, respectively. When such a target molecule has been identified, the next step is to find active agents that bind to the target molecule.

### What is a binding pocket?

Areas on the surface of molecules that are essential for their activity are so-called binding pockets or active centers. Usually, these areas are like a groove on the surface and offer ideal surroundings for other molecules to bind here. In such cases, the molecules fit as a key in the corresponding lock, hence this is called the "key-lock principle".

On the right hand side, you see a protein - the acetylcholinesterase - that degrades the small chemical compounds acetylcholin in the human body. Can you identify the binding pocket? Turn the protein using the mouse to spot the binding pocket. If you think you found the pocket, click here to see if you are right.

So you can imagine that a molecule cannot bind any other molecule, just like a key won't fit in the wrong lock, i.e. the binding pocket of a protein is specific for certain molecules. Only these specific molecules can bind to the binding pocket of the protein and induce a reaction in the human body.

Click here to see the complex of two bound molecules. The molecules are colored differently. Do you see how accurately they are fitting?

### How does a drug work?

The active pharmaceutical ingredient of a drug is usually a small molecule that can bind to a specific protein - the target - in the human body. As already explained, the molecule (the key) fits into the binding pocket of the protein (the lock) in a specific manner and, ideally, this specificity is sufficiently unique so that the small molecule will only bind in the binding pocket of the target protein.

On the next page, you learn more about why we need computers in modern drug design.

- Back
- Next