April 2013 marks the 100th anniversary of the birth of an amazing modern science named ‘crystallography’. This is the scientific thread that originated with the description and analysis of those mysterious and amazing pieces of matter that were referred to as ‘crystals’. Characterized by sparkling, well polished and sharply defined faces and intriguing geometrical shapes, crystals have always had a fascinating effect on humans. Their forms inspire awe, mystery, and many people are prone to ascribe powerful forces to crystals, including healing powers. Crystalline precious stones such as diamonds, saphires, rubies and others are typically connected to wealth, influence, power through history and have been treasured avariciously by humans for generations.
In April 1913 in the United Kingdom, the Braggs (William Henry and Willian Lawrence, father and son) managed to unveil the atomic structure of simple common salts such as (Sodium Chloride, table salt) by puting crystals of such substances in front of an unknown form of radiation, appropriately named X-rays. These mysterious rays had been discovered barely a decade earlier (1895) by the German physicist W. Roentgen. The experiments and their interpretation brought together the power of crystals and X-rays. Incidently, also in April (1953), Watson and Crick proposed their seminal three-dimensional structure of DNA based on the diffraction data obtained by Rosalind E. Franklin exposing fibers of the genetic material to the same enigmatic X-rays. The combination of these events has prompted the International Union of Crystallography (IUCr) to declare 2014 the international year of crystallography (www.iycr2014.org).
What made this possible? What was the ‘truly magical power’ of the combination of crystals and X-rays that allowed such a feat? Of course, there was human ingenuity, but the key elements that made this achievement possible were already present in the crystals and in the incoming unfathomable radiation. What are these elements? How do they combine together to unveil the hidden secrets of matter?
Crystallography, as a science or as a field of research, has a dreadful reputation. Always shrouded in a veil of mathematical mystery that apparently only a few can lift to discover its innate beauty. Although the professional crystallographer needs a mathematical background to practice the craft, this does not mean that complex mathematical knowledge is required to understand what crystallographers do. Or the impact of their discoveries. Appreciation and further interest may follow an initial window of understanding into the field. This is what I intend to do with these brief initial sequential essays in this blog. Other topics of interest related to crystals will follow.
There is one further motivation that was also expressed in the introduction to Crystals and Life: A Personal Journey (IUL, 2002) . I have read many books of science addressed to the layperson and I have found many of them terribly dry. A sentence-after-sentence recitation or regurgitation of facts, only broken with a few parentheses to mention who obtained the Nobel Prize for what and on which date. Nowadays, the availability of internet sources has made such approach to convey the scientific enterprise obsolete. We need to present how rich and multifaceted the scientific endeavor is in a different manner: peripatetic, colloquial, narrative, dramatic, literary and even poetic and certainly electronic. Roald Hoffman, Carl Djerassi, Oliver Sacks and others have made major strides along these lines within the domain of chemistry. However, crystallography, hidden behind its mathematical cloak, is still among the orphan sciences in this regard. So far, it seems that it is better to leave it alone. The fundamental discoveries and the names with the appropriate accolades can be obtained from a myriad of sites in the world wide web. Can we, however, convey the basis of crystallography in a condensed, personal, suggestive, inspirational and poetic form?
These are the goals of this brief collection of vignettes around the general theme of crystals, crystallography and the implications of their scientific findings for the understanding of life processes. Because of my professional expertise, I will focus on the study of crystals from biological samples, and especially proteins and biological macromolecules. However, enough material is common to many other applications of crystallography that the reader should be able to extend the ideas easily. A limited glossary would be added along the way to provide the definitions of some of the technical terms used throughout the text and I intent to add notes and references for further reading.
On one side, the crystallographic community has only partially succeeded in communicating the enormous influence that the study of crystals, and the study of matter inside crystals or semi-crystalline materials, has had on our tangible world. On the other hand, the public at large has not realized how the discoveries made in the atomic domain of crystals are affecting their daily lives in areas such as health care or the design of new materials. Moreover, the biomedical sciences stand at the brink of yet another revolution fueled by the influx of information obtained from the unraveling of the gene maps of pathogens and the human genome itself. Mapping the three-dimensional structures of an increasingly larger portion of the proteins coded by those genes is the next challenge in molecular biology. This knowledge will be followed by therapies based on the understanding, inhibition or alteration of the three-dimensional structures of the proteins associated with those genes. How are those structures unveiled? What is the technology behind those spectacular computer images? What do they mean for the synthesis of novel drugs, or the design of new vaccines? What can we expect in the near future? What are the implications of this wealth of new information for our understanding of life’s physico-chemical processes and who we are?
Reading through these brief essays, the reader should be able to assimilate a series of ideas and concepts related to crystallography. She or he will be able to conceptually understand how crystallography works and how crystallographers are able to unveil the molecular structures existing within crystals. Although painted with coarse strokes, there would be historical and conceptual background peppered throughout the text to follow the development of the field and to provide a firm basis for further reading or even study. The initial essays and the structure of these notes are taken from the more extensive book that I published in 2002 entitled Crystals and Life: A Personal Journey (International University Line, 2002). I am grateful to my editor Dr. Igor Tsigelny for allowing me to extract significant amounts of material from the original manuscript to retain the spirit of the narrative in these notes and to present them in electronic form to a wider community. Hopefully, the essays will complement and continue on beyond the content of the book.
Initially, I will present a handfull of essays to introduce the basic concepts of crystallography so that the readers can appreciate its internal beauty and recognize its inmense power. The essays will also identify and pay homage to some of the heroes of the field who developed the concepts, methods and tools to expedite the structural analysis. Depending upon the response, future essays could also illustrate how recent results obtained from crystals or crystalline materials are affecting our standard of living and quality of life in certain specific areas. There is much that could be said about the impact of crystallography in many fields of science. It is in fact a truism that there are more Nobel Prizes related to crystallography as a method, and the results obtained from this science in various domains of research (i.e., structural biology, medicine, materials science), than in any other science or in several branches of science combined.
I do hope that these personal and scientific sketches can be used as an introductory narrative to introduce the science of crystallography to the educated layperson in the electronic web and to the public at large. In addition, any person curious about crystallography and its impact on the biomedical sciences and our world at large could also benefit from reading them. They should be read in sequence first. Like poems, some essays will be easier to read than others, but I encourage you to make an effort to read through all of the basic ones first. Later, some of the essays could be read again for further insight, in a coffee break; others on a quiet Sunday brunch at home or on the train or bus. All can be read anywhere and everywhere. If I succeed in brightening your day with an ‘aha’ of scientific or human understanding, these vignettes will have served their purpose. Hopefully, you may be inspired to read more and discover for yourself the ‘Magic of Crystals’.
Some parts of the text have been excerpted from the introduction to the book ‘Crystals and Life: A Personal Journey” (Abad-Zapatero, IUL, 2002), with permission from the publisher (www.iul-press.us/Books/BSFE01-Magic/magic.html).