.. _subs_buildtasks_psfgen_mods_ssbonds: ssbonds and ssbondsdelete ------------------------- ssbonds ^^^^^^^ .. # shortcode format: C_RRR-D_SSS # C, D chainIDs # RRR, SSS resids An ``ssbonds`` directive is used to specify disulfide bonds between two residues. The syntax for specifying a disulfide bond is as follows: ``_-_`` ```` and ```` are the chain IDs, and ```` and ```` are the residue numbers of the two residues that form the disulfide bond. For example, ``A_12-B_15`` would create a disulfide bond between residue 12 in chain A and residue 15 in chain B. You can use either 1-byte or 3-byte residue names. ssbondsdelete ^^^^^^^^^^^^^ An ``ssbondsdelete`` directive is used to specify the deletion of a disulfide bond between two residues. The syntax for specifying a disulfide bond deletion is as follows: ``_-_`` ```` and ```` are the chain IDs, and ```` and ```` are the residue numbers of the two residues that form the disulfide bond. For example, ``A_12-B_15`` would delete the disulfide bond between residue 12 in chain A and residue 15 in chain B. You can use either 1-byte or 3-byte residue names.