AFITT is a crystallographic tool for correctly placing small molecules in real-space density. AFITT combines our flagship Shape technology with generic forcefields into a new forcefield that fits small molecules into crystallographic density while maintaining excellent chemistry.

AFITT also provides an interface to external refinement programs and tools to validate the refinement including interactive Ramachandran plots and real-space correlation coefficient calculation (RSCC).


The AFITT distribution contains a single application:

  • FLYNN for fitting ligands into real-space density.

Utility Programs

The following utility programs are also included in this distribution:

  • AlignGrid: Utility to align proteins with electron-density maps on a single reference

  • RotFit: Utility to carry out fast automated refitting of side-chains and peptide flips.

  • Rscc: Utility to perform real-space correlation coefficient and real-space R-factor calculations.

  • WriteDict: Refinement dictionary generator that properly handles covalent bond restraints between the ligand and the protein