You may set the CHAIN character to one of the following special chatacters:<br>
<b>.</b>&nbsp;&nbsp;Choose first chain in the PDB file.<br>
<b>+</b>&nbsp;&nbsp;Use all protein atoms, no ligands, no waters.<br>
<b>@</b>&nbsp;&nbsp;Use all protein and water atoms, no ligands<br>
<b>%</b>&nbsp;&nbsp;Use all atoms in the PDB file. <br>