The general strategy for setting up the molecular
structure for a combination of proteins, water,
substrates, ligands, and/or nucleic acids is:
Split the original coordinate file into several files containing the segments.
A segment is defined as a protein with one continuous
polypeptide chain, a continuous protein chain, a substrate, a cofactor, a
ligand, all water molecules combined, or a single nucleic acid strand.
Generate each segment separately.
If necessary, apply appropriate patches to establish covalent links
between segments or within segments, such as disulfide bridges.