Recipes for the protein crystallographer

Abstract

Practical Protein Crystallography by Duncan E McRee Academic Press 1993, 386 pages. £35/$70 hardback (ISBN 0-12-486050-8).The area of protein crystallography has not been flooded with textbooks. After the classical Blundell and Johnson text appeared in 1976, not a single crystallography textbook focussing on protein crystallography has been published. Interested students have to consult more general texts on X-ray crystallography which devote not more than one or two chapters to proteins.Duncan McRee has done an excellent job in presenting his personal experience in this field. He writes in a casual style which makes reading easy. The title of this book truly covers its content. It is exclusively devoted to practical problems in protein X-ray crystallography. Chapter 1, on Laboratory Techniques, gives details about protein sample preparation and crystal growth, and storing and soaking of crystals. In chapter 2, data collection techniques are discussedin extenso, including crystal mounting, X-ray sources, strategies and data reduction. Chapter 3 is equally useful. It presents data processing and the solution of the phase problem, including the necessary elementary terminology, such as R-factors, space groups, and resolution. After the more general chapters 1–3, the book becomes a real cookbook. In 60 pages the author discusses eight specific problems from his own work and from the work of his colleagues at the Scripps Research Institute. Four of the examples concern multiple isomorphous replacement (40 pages) with only one example (3 pages) of molecular replacement, which is somewhat surprising in view of the extensive application of this technique for structure determination. The remaining three examples are on mutant studies and substrate-analog binding. These examples can be illuminating for the student who is struggling with his/her own structure. In the remaining 80 pages of the book, software is discussed. This is of only limited interest to most protein crystallographers because it focuses on the specific package (Xtal View) used in the author's laboratory.The book is not free of errors. Apart from an occasional printing error, it also contains some technical errors (for example, on page 33; in the X-ray tube drawing the tube current is indicated as the filament current, and in the legend to this figure it is stated that the filament is 40 kV above the target (anode), whereas in fact it is below). It is also sloppy to write: “soaking in an inhibitor or heavy atom”. One easily forgives the author these imperfections, however, because of the pleasant way in which he addresses the reader. The question is: what sort of reader? The experienced protein crystallographer will recognize the problems discussed and may have the same or different solutions for them. The absolute beginner and those with hardly any background in crystallography will have great difficulty, because the most elementary concepts (such as Ewald sphere and reciprocal lattice) are used but not explained. If there is an explanation it is in a dictionary-like style. Theory is not dealt with at all, and readers needing to understand diffraction and structure determination are referred to the literature (e.g. Blundell and Johnson, and Methods in Enzymology, Vol. 114 and 115). Therefore, this book is not a textbook for the beginner but a manual for the laboratory. The book will be appreciated most by the student who has already made a start in protein crystallography and who knows and understands what he/she is doing. Such students will find it instructive to learn from the author's extensive experience and to find out that the standard techniques in their own laboratory are not the only ones in the world. As a manual the book is highly useful and should be on the shelf in every protein crystallography laboratory.