This year has been named by the United Nations as the International Year of Crystallography. For those without a scientific background, and for many with one, looks of puzzlement and confusion usually appear about now during conversations on this topic. It is this reaction that the UN are trying to combat, making general public more aware of the fairly obscure science that is crystallography, and showcasing the huge leaps of understanding in many areas of science that are due to it.
2014 is an appropriate choice to host this year of recognition of crystallography, falling on the centennial anniversary of the awarding of Max von Laue’s Noel Prize in Physics. Von Laue, a German physicist, was awarded the prize for his “discovery of the diffraction of x-rays by crystals”. His work heralded the age of crystallography, allowing the father-son team of Sir William Bragg and Sir Lawrence Bragg to do further work with crystals and ultimately discover that x-rays could be used to see the interior of a crystallised compound without interfering with it, an achievement for which they were also awarded the Noble Prize for Physics.
The main part of their work was the invention of the modestly named Bragg Diffraction Pattern in response to a lack of information about the interior of molecules. In general, in the realm of light microscopy, a small object can be viewed using a lens to focus the illuminating radiation, or light. Visible light, however, is usually of a wavelength between 4000 and 7000 ångströms (Å) (one ångström is one-tenth of a nanometre or one ten-billionth of a metre). This is almost three orders of magnitude longer than the length of an atomic bond (the connection between atoms allowing them to construct more complicated structures), which weighs in in the region of 1 to 2 Å. To combat this problem, shorter wavelengths of radiation, such as x-rays and neutron beams were employed. Using these types of radiation posed another problem however, as there was no way of focusing radiation of such a short length.
This is where the Bragg Diffraction Pattern comes in. By analysing the spots or “reflections” in the pattern, the structure of the sample may be discovered. Sharper images were obtained from samples with a high density and a constant repetition of atomic order, as more light was focused on one particular point, whereas random atomic order cause light to be thrown in all directions. This simple fact made crystals, with their highly ordered internal arrangement, the perfect choice for studying compounds using this technique.
So what impact has this made of the world today? To be fair, crystallography has a huge impact on the way we view the world today, especially in creating new information for the sciences, but also in allowing more affective drugs to be created.
The most noteworthy story in which this science played a role is possibly one of the most important and well known of recent science; the discovery of the double helical structure of DNA. In 1952, Raymond Gosling, a PhD student in the lab of Rosalind Franklin, took Photo 51, the nickname given to an image of the x-ray diffraction pattern of DNA. This photo was shown to James Watson and Francis Crick, who used the characteristics shown by the photo to construct a chemical model of the structure of DNA. This was a vital break-through, as the discovery of the structure of DNA allowed others to learn how hereditary information is passed from the parents into their offspring. However, the story is not without controversy. Watson was apparently shown the image without Franklin’s consent, and the paper on the structure only hinted at her contribution to the discovery. It is for this reason that her role and the role of crystallography are often overlooked in this paradigm shift in the way we think about information transfer in the body.
Crystallography has also allowed, in more recent years, the discovery of the structure of G-Protein Coupled Receptors (GPCRs), receptors on the membrane of all cells that control a huge amount of physiological response within the body. They are the target of almost 60% of all drugs, and the 2012 Nobel Prize in Chemistry was awarded to two men, Brian Kobilka and Robert Lefkowitz, for their work on discovering the structure of these receptors, allowing more effective drugs to be derived, benefitting millions of people worldwide.
Moving back to the present, the UN has requested the UN Educational, Scientific and Cultural Organisation (UNESCO) to lead and coordinate “the planning and implementation of educational and capacity-building activities during the year.” The main events are the opening of crystallography laboratories in Asia, Africa and Latin America throughout the year, a number of summits occurring across the globe, and the organisation of public awareness events such as hands-on Crystallography Open Laboratories, the launch of an open-access crystallography journal, and the arrangement of crystal-growing competitions, to name but a few. More information on nearby events and on crystallography in general can be found online at iycr2014.org, for those interested in this fascinating area of science.