This set contains the polar amino acids. All amino acids are classified as either hydrophobic or polar. The set of all atoms in proteins. This consists of the RasMol predefined set amino and common post-translation modifications. The set of purine nucleotides.
All nucleotides are either purines or pyrimidines.
The set of pyrimidine nucleotides. All nucleotides are either purines or pyrimidines. This set contains the set of atoms in the currently selected region. The currently selected region is defined by the preceding select or restrict command and not the atom expression containing the selected keyword. This set contains all atoms that form part of a protein beta sheet as determined by either the PDB file author or Kabsch and Sander's DSSP algorithm.