(37) Sclove, Stanley L., and Sherman, Simon A. (1997). A priori and a posteriori mixture distributions for using databases in protein structure determination. Journal of Molecular Structure (Theochem) 419 245-255.
The twists and turns of protein molecules correspond to the rotational angles of the main and side chains in their constituent amino acide residues. Owing to stereochemical restrictions the joint distribution of these angles falls into several well-separated clusters. Consequently, we fit a statistical finite mixture model to data from the Brookhaven Protein Data Bank (PDB), obtaining a new classificaiton of conformational states of amino acids. The results of this database modeling are important for knowledge-based approaches to protein structure determination and analysis and can be used in conjunction with experimental data in the determination of protein spatial structure. As part of this process, the mixture distributions wer have fit can be used as a priori distributions. A posteriori distributions corresponding to these a priori mixture distributions are illustrated.