[Daresbury Laboratory] The CCP4 Program Suite is an integrated set of programs for protein crystallography. It is distributed in source form (mostly Fortran), supported for VMS and various Unix platforms.
[S. Hubbard & J. Thornton, UMIST] A stand alone program that calculates the accessible area of a molecule from a PDB format file. It can calculate the atomic and residual accessiblities for both proteins and nucleic acids.
[ACRM] Torsion is a program for calculating phi, psi, omega, and C-alpha pseudo-torsions.