What are x-ray fragment based drug discovery experiments?

Question

And why are the guys on twitter so happy for the poster?

https://www.twitter.com/MartinWalshDLS/status/1236355083585179648?s=19

In: Chemistry

Answer 1

Scientists have to figure out the molecular structures of proteins and molecules (how the atoms are connected and the overall shape).
One way to do this is by a method called X-ray diffraction (XRD). It is an older method and is often used to figure out the structure of large molecules and especially proteins. It works like this:
-first, you grow a small crystal of the compound that you want to study (yes, some proteins can actually form crystals)
-you irradiate them with xrays from various angles. Behind the crystal you put a detector or a special plate. Depending on the angle, you detect different patterns of dots called diffraction patterns.
-A computer can take all the diffraction patterns and calculate a molecular structure of the compound.

Knowing the structure of important proteins helps you to design drugs that inhibit them.
In this case, they figured out the structure of an important enzyme of the new coronavirus. It is a type of enzyme called protease that the virus needs to assemble itself, and proteases are often targets for antiviral drugs (protease inhibitors).