• macromolecular crystallography;
  • computer programs;
  • Python;
  • mmCIF;
  • PDB.

The Python Macromolecular Library (mmLib) is a software toolkit and library of routines for the analysis and manipulation of macromolecular structural models, implemented in the Python programming language. It is accessed via a layered object-oriented application programming interface, and provides a range of useful software components for parsing mmCIF, PDB and MTZ files, a library of atomic elements and monomers, an object-oriented data structure describing biological macromolecules, and an OpenGL molecular viewer. The mmLib data model is designed to provide easy access to the various levels of detail needed to implement high-level application programs for macromolecular crystallography, NMR, modeling and visualization. We describe here the establishment of mmLib as a collaborative open-source code base, and the use of mmLib to implement several simple illustrative application programs.