<li>
Only standard codes of aminoacids are recognized in PDB files.
<li>
+PDB files can be downloaded from the PDB database based on given PDB code.
+To select only a single chain use PDB_code:chain_id notation (for example
+5G3Q:B), chain_id is case sensitive.
+<li>
Unres server requires input PDB files with continuous (without breaks)
protein chains. PDB files with gaps in the structure have to be first prepared
by filling up all missing residues. There is a plan to add such service to