Is there a way to figure out what percentage of entries in PDB have SS bonds? In addition, what other types of bonds in PDB may be worth looking into (not H bonds)?


1 Answer 1


The easiest way is to check annotations in mmCIF or PDB files.

Looking at my page with statistics of mmCIF tags, last updated in March:

_struct_conn_type.id        59137×metalc 42706×covale 36195×disulf 10725×hydrog
_struct_conn.conn_type_id   5350402×hydrog 1733277×metalc 559092×covale 226472×disulf

Which means 226472 disulfide bonds in 36195 PDB entries at the time when the PDB had 161470 entries.

  • $\begingroup$ Great, thanks! Exactly what I needed. What about ionic interaction (salt bridges), do you have the numbers? $\endgroup$
    – Jake B.
    Oct 6, 2020 at 18:03
  • $\begingroup$ No, I'm afraid I can't help with salt bridges. $\endgroup$
    – marcin
    Oct 6, 2020 at 20:29

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.