All biological processes are regulated and executed by nucleic acids (DNA) and proteins (proteins). These processes can only be understood if the spatial structures of such complex macromolecules and in particular the geometry of their active centres are known in atomic detail. Since nucleic acids, proteins and even intact viruses can be crystallized, they are accessible for X-ray structure analysis, which has given crystallography a key function in molecular biology.
Genetic engineering allows a protein to be altered structurally and thus functionally to a large extent. This “protein design” is only possible if the structure of the respective protein is known, which has further increased the need for structural analysis. Methodological innovations, such as the development of area counters and the availability of intensive synchrotron radiation, allow the rapid measurement of the extensive data. More efficient computers and graphic screens allow on-line interpretation of data and display of complicated structures. Computer simulations expand structural analysis and “protein design” because they represent dynamic processes in a time-dependent manner, especially complex formation with smaller molecules that have a regulating effect on proteins.
Essential for “protein design” is the availability of ever more extensive databases, which mainly contain crystallographically obtained structural data. Crystallography thus provides important insights into biology for basic research and has opened up new opportunities in medical and pharmaceutical research.