Experimental methods in structural biology: Protein crystallization, structure determination by X-ray crystallography, SAXS, Cryo-EM and NMR spectroscopy


In this chapter I discuss the basics of the major experimental methods used in tertiary protein structure determination. Among those is protein crystallography, which has contributed most to our knowledge of protein structures, NMR spectroscopy, electron microscopy (and spesially Cryo-EM) and the rapidly developing method of small-angle X-ray scattering (SAXS). The first page is a general introduction, which is currently followed by specific parts on protein crystallization and protein crystallography. More parts will be added later.
Introduction

People often say: Crystallization is an art and not a science. It is true to a certain degree, there are still some general principles which need to be followed, and most importantly, there are different methods, which have been developed to facilitate protein crystallization. In this part I will provide an overview of the method and subsequently I will add more details on the theory and methods used in protein crystallization.
Crystallization
Crystallization tools

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After obtaining crystals it is time for the actual X-ray crystallographic experiment, which is essentially placing the crystal in an X-ray beam and collecting diffraction data. Once data have been obtained, the rest of the work will be done using specialized computer programs. To start with, I will first give an overview of the method of X-ray crystallography, followed by introduction to the theoretical basics of X-ray diffraction: Crystals and symmetry, the theory of X-ray diffraction, X-ray data collection and structure determination, model building and refinement, and finally assessment of the quality of the structure.
Protein crystallography : Protein characterization and crystallization
Protein crystallography 2 : X-ray data collection and processing
Structure quality