void OEPerceiveResidues(OEMolBase &mol,
                        unsigned int stable=OEPreserveResInfo::None)

Recognizes the protein and nucleic acid chains of a molecule and set the residue information for each atom appropriately. The stable parameter is a bit-mask defined in the OEPreserveResInfo namespace that indicates if the residue numbers, residue names, or chain ID’s should be preserved during the perception routine. By default, no prior information is preserved.