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Mirror Molecules?

Date: (2/10/2009)

Facultad de Ciencias Químicas

“There are mirror molecules which have the atoms linked in the same way, but they are not the same molecule.” A molecule can be the mirror of the other one. One of the techniques for characterized them is through X-ray diffraction:” Doctor Sylvain Jean Bernes Flouriot.

X-ray diffraction allows us to assure the active principle sold for a medication, it is which gives the biological effect.

By Gabriela Hernandez Villanueva

It comes from: Atoms, Molecules and Their Structure

The atoms are linked by chemical links and they generate molecules. Determine a molecule’s structure means that researches recognize –for example- sulfur atom is in a certain place and not in another one, that there is a brome atom and beyond a nitrogen atom, all of this in a three-dimensional structure.

Around 50 million different chemical compounds are known, and only one percent can be characterized through X-ray diffraction technique.

“Diffraction method allows us to see –directly- what the matter has inside, but there is a condition that is like a bottle’s neck for being applied, the matter has to be crystalline. That is why just one percent of the molecules that can be characterized through this technique, because not everything can be crystallized.”

“The molecules that got all the necessary are inserted inside the crystal and for seeing them, currently (and probably, for more time) we use diffraction technique, because any electronic microscope is enough powerful in order to have enlargement factor which allows us to see them.”

“I am participating in a projects’ stage that can be essential or maybe cannot help a lot in my colleagues’ researches; this depends –totally- on the molecule,” said Doctor Sylvain Jean Bernes, the Universidad Autonoma de Nuevo Leon (UANL) School of Chemistry (FCQ, Spanish abbreviation) researcher.

FCQ professor receives products synthesized in crystalline status by other researches. Their work is to generate diffraction phenomenon and define these products’ molecular structure.

“We have specialized equipment in the laboratory, there is a X-ray source, a system that conduces the crystal and measures a diffraction pattern, as well as a software that will carry out endless steps which allow us to transform diffraction pattern in atomic projections,” said Doctor Sylvain Jean Bernes.

Procedures’ time vary according to the type of molecule we work with. The difficulty for developing X-ray diffraction technique depends on crystals’ quality (pure) and different technical matters which take part in the process. At the end, the scientist gives to his colleagues the molecule’s three-dimensional model where every sphere is an atom.


Application

Imagine a project where we try to synthesize and improve a well-known medication used for treat a disease.

There are molecules inside of the medication, and a small modification is applied on them in order to get the same effects with a better impact or with less secondary effects.

When the chemicals synthesize a new molecule, they do not know if what they modified was molecule’s active principle –they did have- or not. For knowing what the modification is, one of the techniques is to determine its structure.

“Once, they know how all the atoms are put, they got molecule’s formula and they know what they did. In other words, that technique tells them what they did and which is the chemical modification they applied on the molecule.”

“Even though, in the medication is more difficult to remove the effects than increase the effect we wanted in the molecule, the main objective is to modify it lightly, and medication’s active principle hoping to decrease the effects,” said Dr. Sylvain Jean Bernes.

It is essential to determine the molecular structure when the active principles get ready in the pharmaceutical industry and other ones, because they have to be proved if the molecule is prepared or its mirror.

“There are molecules which have linked atoms in the same way, but they are not the same molecule. A molecule can be another one’s image on a mirror, and one of the techniques to characterize them is through the X-ray:” Doctor Sylvain Jean Bernes Flouriot.

“It is essential to define the molecular structure of these particles because when a molecule is the active principle such as medication’s active principle, and the molecule that is being used is the mirror, this will not give any biological effect or even, it might have a lethal effect.”

“The technique that allows us to know if the researches prepared the correct molecule or the opposite one –without considering other molecules- is X-ray diffraction,” specified Doctor Sylvain Jean Bernes.

Legally, everytime that a laboratory prepares an 1102 pounds batch of a medication’s active principle, it is necessary to crystallize a part of the prepared batch and determine its structure in order to be sure that what they prepared is the molecule they wanted to. Any medication can be sold until get the report that proves that the active ingredient was what they were looking for.

So, X-ray diffraction assures that the active principle sold for a medication is which gives the biological effect we wait for.