PREQUEST: A DATA INPUT PROGRAM FOR THE CAMBRIDGE STRUCTURAL DATABASE. Paul Edgington, Clare Macrae, Sam Motherwell, Cambridge Crystallographic Data Centre, 12 Union Rd., Cambridge, CB2 lEZ. UK

The Prequest program enables users to create new entries for the Cambridge Structural Database (CSD) from common input formats such as CIF and SHELX. Important checks are made for validity and self-consistency of data fields, enabling users to add entries to a local (private) CSD database fully searchable with Quest. This gives the user a method for quickly comparing molecular geometry parameters of current experimental results with the main CSD.

The program also prepares the way for trouble-free depositing of data with the Cambridge Crystallographic Data Centre (CCDC), as private communications to be added to the widely distributed main CSD file.

The use of the CIF input format is now well established. Prequest gives a friendly interface with which to check out the content of a CIF file, giving interactive graphic display of the 3D molecular structure. Messages are given if items normally expected in CSD entries are missing from the CIF.

Prequest also accepts other common formats such as SHELX. Cartesian coordinates from modelling or theoretical calculations may be input in MOL2 format. Fragments of proteins may be inserted from PDB format with automatic generation of connections and bond types.

Generation of 2D chemical diagrams with bond-type from the 3D coordinates is provided, either automatically or by direct 2D drawing. Checks are made for matching of 2D/3D connectivity before storage.

For further details see http://www.ccdc.cam.ac.uk