O is a general purpose macromolecular modelling environment. The program is aimed at scientists with a need to model, build and display macromolecules. Unlike other molecular modelling programs, such as FRODO [4], O is a graphical display program built on top of a versatile database system. All molecular data is kept in this database, in a predefined datastructure. However, any data can be stored in the database. Data produced by associated, stand-alone programs can very easily be stored in the database, and used by the program, for example for colouring of atoms.
The powerful macro facility of O enables the user to customize the use of the program to satisfy his or her specific needs. The current version of O is mainly aimed at the field of protein crystallography, bringing into use several new tools, which ease the building of models into electron density, allowing this to be done faster and more correctly. Notably, some new autobuild options greatly enhance the speed of building and rebuilding molecular models.
The program is the work of Alwyn Jones and Morten Kjeldgaard.