ABSTRACT
Structural biology has had an enormous influence on biochemistry in general, and on the study of proteins in particular. It can almost be said that unless we know a protein’s three-dimensional structure we cannot understand how it functions. However, when the crystallographer John Kendrew determined the structure of the first protein to be described in detail (myoglobin, in 1958), the most striking feature was its irregularity and complexity (or, as Max Perutz wrote, a “hideous and visceral-looking object”—Figure 1.1 [2]). It soon became clear that proteins require this level of complexity to bind ligands and catalyze reactions specifically. But as soon as we start looking in detail at proteins, we see that there are regular patterns to the way in which proteins fold up, patterns that are determined by the underlying structures of amino acids and by the forces that dictate how they pack together. When we look at the human body, we can identify a hierarchy of structural and functional units, each dependent on the next: limbs, organs, cells, and cellular components. The same is true of proteins-each level of structure (quaternary, tertiary, secondary, and primary) depends on the one below.
