The DSSP program was designed by Wolfgang Kabsch and Chris Sander to standardize secondary structure assignment. DSSP is a database of secondary structure assignments (and much more) for all protein entries in the Protein Data Bank (PDB). DSSP is also the program that calculates DSSP entries from PDB entries. DSSP does not predict secondary structure.
If you use DSSP, please quote:
Dictionary of protein secondary structure: pattern recognition of
hydrogen-bonded and geometrical features.
Kabsch W, Sander C,
Biopolymers. 1983 22 2577-2637. PMID: 6667333; UI: 84128824.
A series of PDB related databases for everyday needs.
Joosten RP, Te Beek TAH, Krieger E, Hekkelman ML, Hooft RWW, Schneider R, Sander C, Vriend G,
NAR 2010; doi: 10.1093/nar/gkq1105. (PDF).
In 2011 Maarten Hekkelman has written new software that produces the same output as the original DSSP, but that deals better with the many exceptions life and the PDB throw at us. And the new software is much faster and easier to maintain in the future too. To not confuse the topic too much, we call this new software DSSP. The original DSSP will be referred to as DSSPold.
The source code of DSSPold (as patched, corrected, and optimised by Elmar Krieger in the beginning of this century) is still available (and works fine). The new DSSP, is distributed as executable only. You can get the new DSSP source code only if you can convince us that it is really needed for a worthy scientific cause.
DSSP is distributed on a basis of trust. You send the license agreement and you download the software (either the source code including distribution of DSSPold, or the executable of DSSP; whatever you want). If you are a commercial entity, the same rules hold for the new DSSP. So, as of 'now' (July 8 2011) DSSP is free of cost for everybody.
We provide a series of DSSP related facilities that are explained partly in these DSSP pages, and partly elsewhere in the PDBfacilities pages.