DSSP (Define Secondary Structure of Proteins) is an algorithm written by Wolfgang Kabsch and Chris Sander (1983) to assign secondary structure information to the amino acids of a protein. BotDB here provides a DSSP Analysis tool which summarizes secondary structure information by counting individual alpha helices, 3- and 5- helices, beta strands, beta bridges, hydrogen bonded turns, bends as well as other non-structural information.
A PDB file format is different from a DSSP file format and therefore will not produce desired results.
You may download DSSP files from the Centre for Molecular and Biomolecular Informatics (CMBI) FTP site. To view an example of a DSSP file at the CMBI, click here. To view a DSSP summary file after running the analysis tool at BotDB, click here.