Tools for limited proteolysis studies
X-ray crystallography and two-dimensional nuclear magnetic resonance (NMR) remain the methods of choice for determining the high-resolution three-dimensional structure of globular proteins. However, not every laboratory has the equipment and expertise required for these physicochemical methods. Before a protein can be examined by X-ray crystallography, it must first be crystallized. Some proteins form crystals more readily than others, and discovering the precise conditions needed for the crystallization of a given protein is rarely a trivial pursuit. Likewise, NMR studies require concentrated protein solutions containing no aggregates. Protein structure can also be studied, albeit at much lower resolution, by classical biochemical methods such as limited proteolysis. Also known as partial or controlled proteolysis, this approach is relatively inexpensive and generally easy. Partial proteolysis studies can provide useful structural information to complement that derived from higher-resolution techniques. A brief review of some of the basics of protein...