Report 79 16 Structure and Function of the

The long term practical goal of this work is the creation of a fully automated system for protein structure determination, starting with data collection and ending with an accurate 3-D model of the molecule. Most of the software already exists at the two ends of the process. At the "front end", programs exist for reducing and transforming the x-ray diffraction data, and estimating phases. The result of this processing Is an electron density map (EDM), which gives a blurred view of the electron cloud surrounding the molecule. At the "back end" are a variety of numerical techniques for taking a full or partial model of the protein and iteratively refining the atomic coordinates so that the model is a best compromise between one which best fits the data and one which best matches Ideal stereochemical constraints [Hermans74] [Agarwal77].