This application provides a visual and pedagogical tool to understand the Ramachandran basin of different residues. The library is generated by culling a library of non-redundant X-ray structures from the PDB. The following libraries are described in more detail in  our work [download pdf] (Biochemistry, 2005):

Entire PDB
A library of 2020 chains (X-ray structure; n > 20 residues, homology < 25%, R < 0.3, Resol. > 2Å
PDB- helix & sheet From the "Entire PDB" library by removing helices and sheet as defined by DSSP.
PDB- helix, sheet and turns
From the "Entire PDB" library by removing helices, sheet and turns as defined by DSSP.
Coil Library
Filtering for fragments smaller than 4 residues and by removing the end residues.