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Number of Disulfide Bonds

Disulfide bonds in protein structures are covalent bonds between the sulfur atoms of cysteine residues. They play an important role in the stability and folding of proteins.

Disulfide bonds are annotated by SSBOND records in the PDB file and in the _struct_conn category of the mmCIF file.

This search allows querying the PDB by the total number of disulfide bonds in all chains of asymmetric unit.


  1. Enter "Between 20 and 20" to find all structures that have exactly 20 disulfide bonds.
  2. Enter 50 in the left box and leave the right box empty to find all structures that have at least 50 disulfide bonds.