Protein Structure and Function is an introduction for postgenomic biologists to the structural basis for the biological activities of proteins, with special emphasis on the interpretation of gene sequence in terms of protein function. Early chapters discuss the determinants of folding and stability and of secondary, tertiary and quaternary structure, the universe of protein folds, and superfamilies and motifs in the analysis of protein function, as well as the basic principles of protein function, with major sections on ligand binding and enzyme catalysis. Later chapters describe the regulation of protein function and how proteins work as switches, machines and motors, and discuss the contribution of comparative structural analysis to the understanding of the relationship between sequence, structure and function. The book ends with a short chapter on how the structures of proteins are determined.