Scientists from the Department of Energy’s lab at Argonne, have devised a way to have a gas-cloud of molecules align itself in the same way (press release here). This is very significant as it allows scientists to decipher the structure of said molecules without having to crystallize them.

You see, the major way to figure out the structure of molecules and such, is by a technique called x-ray diffraction. It basically shoots in a very powerful x-ray beam (from a source called a synchrotron), and causes it to diffract off it, creating a pattern image. You can think of it kind of like shining light at an object and then looking at it’s shadow to figure out what it looks like (a simplification of course, but you get the idea). The problem with this though, is that each atom will diffract (cast a shadow) in a different way depending on how it is aligned, and unless they are all set in a periodic lattice (also called crystal), it is impossible to understand the diffraction picture and gain any information from it (for an example of a periodic lattice check out the picture for this article). So for example while you would be able to do x-ray diffraction on a crystal, you could not perform it on a gas-cloud, as the distance between atoms there is random and they do not align themselves in any periodic way.

Because of this, scientists have had to crystallize proteins and such that they wanted to investigate (in fact x-ray diffraction was heavily used to investigate DNA when it was found, that’s how they found out it was helical), but there is one major problem, many proteins, including many in drug interaction, can’t be crystallized, and that is where this new technique comes in. Using a laser, they claim to be able to align the molecules in a gas in a periodic way so that it can be used in x-ray diffraction. This would obviously be a huge thing as there are so many proteins (in the human body among other places) that have not yet been investigated.

It should be noted though, that they say they have achieved alignment and theoretically shown that it could be used for x-ray diffraction. They have only achieved the laser periodicity, not actually performed x-ray diffraction on it. On a slightly more personal note, i got to witness the x-ray diffraction of a crystallized molecule a few months ago, and frankly it seemed like a huge hassle, they had to keep it on liquid nitrogen, fish out a tiny sample and mount it in front of the beam. In the end, the sample we saw her (the scientist) image ended up having to be discarded because there was some water vapor that had set on the crystal (if i remember correctly), meaning she had to do it all over again. So I’m sure this is something that will be welcomed with open arms in that community.