TOWARDS A REFERENCE LIBRARY OF MONOMERS. Jean Richelle and Alexei Vagin, Unit de Conformation des Macromolcules, Biologiques Universit Libre de Bruxelles, av. FD Roosevelt 50, CP 160/166, B-1050 Brussels, Belgium

When dealing with an archive composed of a large set of files of macromolecular structures, the correctness, completeness, and coherence of the information in the data files are critical. One of the roles of the mmCIF dictionary is to ensure correctness and completeness. The 'Reference Library of Monomers' is aimed at providing the description of the templates of all the monomers that can be used to guarantee the coherence of the whole set of CIFs. The Library is composed on one hand of a Dictionary, defining the categorie in CIF format, and on the other of the Reference Files, describing the monomer templates as well as parameters for energy calculation.

The talk will describe the conceptual schema of the Library; the main design decisions which lead to this schema will be discussed and the different CIF categories will be explained.

Next the contents of the Reference Files, i.e. types of monomers - amino acids, carbohydrates, ligands, etc. - and energy parameters will be reviewed.

Finally the sources of information used to build the Reference Files will be discussed. Currently the data files of the Protein DataBank (PDB) are the primary source of monomer description; the tools to extract this information will be described. Other sources will be discussed as well.