Protein Purification: Principles and Trends

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of adjacent amino acid residues. The sequence of amino acids in a protein is defined by the sequence of a gene, which is encoded in the genetic code. In general, the genetic code specifies 20 standard amino acids; however, in certain organisms the genetic code can include selenocysteine and certain archaea pyrrolysine. Shortly after or even during synthesis, the residues in a protein are often chemically modified by posttranslational modification, which alters the physical and chemical properties, folding, stability, activity, and ultimately, the function of the proteins. Sometimes proteins have non-peptide groups attached, which can be called prosthetic groups or cofactors. Proteins can also work together to achieve a particular function, and they often associate to form stable protein complexes. The complexity and sheer number of proteins in a cell are impediments to identifying proteins of interest or purifying proteins for function and structure analysis. Thus, reducing the complexity of a protein sample or in some cases purifying a protein to homogeneity is necessary. The latest manual in the Basic Methods series contains a collection of convenient and easy to use protein purification protocols along with a sampling of dependable methods for assessing protein-protein interactions. The protocols are supported by background information to assist researchers in understanding how the purification methods work and how to optimize and troubleshoot the methods. This book contains tested methods for preparing cellular and subcellular extracts- a critical and often neglected step in successful protein purification. The book also covers other areas like Cellular localization, Structure prediction and simulation, which can be a reference book for researchers.