ABSTRACT
The structures described in this book have been determined by physical methods: most of them by x-ray crystallography, some of the smaller ones by nuclear magnetic resonance (NMR). We conclude the book with a short description of these techniques. It is not our aim to convert biologists into x-ray crystallographers and NMR spectroscopists; a complete explanation of the physical basis of these techniques and of the methods as currently practiced would fill more than one textbook. Our purpose is rather to convey the essence of the principles and procedures involved, so as to provide a general understanding of what is entailed in solving protein structures by these means. We will see how deriving a three-dimensional protein structure from x-ray or NMR data depends not only on the quality of the data themselves, but also on biochemical and sometimes genetic information that are essential to their interpretation.
