Protein crystallography: a concise guide, by Eaton E. Lattman and Patrick J. Loll
With their book Protein Crystallography: A Concise Guide, Eaton E. Lattman and Patrick J. Loll endeavoured to offer ‘a trip through the essentials of crystallography’ and they managed to hit the mark. The short book (112 pages plus an 18-page glossary) is predominantly addressed to newcomers in the field of protein crystallography and it definitely is an excellent introduction to the topic. As also stated by the authors, it will not turn the reader into an expert, but it allows newcomers to get started. Having worked through the book, they will be able to digest more comprehensive texts on the topic, and what is even more important, they will be able to critically read scientific articles on macromolecular structures which have been determined by X-ray crystallography. The book is divided into seven chapters, each of them about 15 pages long, and it is extremely straightforward to read. Each individual chapter is easy to comprehend by itself, and the reader is guided smoothly from one topic to the next, sometimes without even noticing that a new area of protein crystallography has been entered. Following the seven chapters is a glossary, which includes many of the essential terms of a crystallographer’s day-to-day language. In the introduction (Chapter 1), the reader gets acquainted with protein crystallography as an imaging process. X-rays are introduced, as are diffraction patterns, electron densities and different ways of visualizing protein structures. Furthermore, a gallery of protein crystals is depicted and a very brief excursion into symmetry is made. In Chapter 2 (Physical Understanding of Diffraction), the phenomenon of diffraction is described and explained, starting from one-dimensional crystals as the simplest case. The authors also describe an easy laser diffraction experiment, which can be set up in the lab or in a classroom without difficulty. Newcomers to the field will be thrilled by the do-it-yourself character of this example. The authors also succeed in deriving and presenting the fundamentals of the Fourier Transformation clearly and intuitively. The ‘trip through the essentials of crystallography’ continues in Chapter 3, which is the central and probably most important chapter, since it deals with diffraction from three-dimensional crystals. The reader is guided step by step towards the understanding of how the discrete spots in the diffraction pattern are generated. Following the authors’ route is absolutely intuitive for the novice. After introducing Miller indices and Bragg’s Law, the authors move on to the two fundamental equations of crystallography, the structure factor equation and the electron density equation. The following three chapters (4, 5 and 6) deal with the phase problem in crystallography and how to derive phase information. Chapter 4 describes multiple isomorphous replacement (MIR) andmultiple wavelength anomalous dispersion (MAD) as the primary approaches for phase determination in the absence of a similar structure. Much time and effort is spent on the explanation of phase circle constructions for both MIR and MAD. The evident relationship between MIR and MAD is highlighted at several points. The final paragraph of this chapter on fitting atomic models to electron density maps seems