I have the following settings in PyCharm:

enter image description here

BioPython is properly installed:

enter image description here


from Bio.PDB import PDBParser
from Bio.PDB.DSSP import DSSP
p = PDBParser()
structure = p.get_structure("16PK", "16pk.pdb")
model = structure[0]
dssp = DSSP(model, "16pk.pdb")
a_key = list(dssp.keys())[2]


C:\ProgramData\Miniconda3\python.exe C:/Users/pc/source/repos/DSSP_algoritm_test/dssp_test.py
Traceback (most recent call last):
  File "C:\Users\pc\source\repos\DSSP_algoritm_test\dssp_test.py", line 6, in <module>
    dssp = DSSP(model, "16pk.pdb")
  File "C:\ProgramData\Miniconda3\lib\site-packages\Bio\PDB\DSSP.py", line 437, in __init__
    dssp_dict, dssp_keys = dssp_dict_from_pdb_file(in_file, dssp)
  File "C:\ProgramData\Miniconda3\lib\site-packages\Bio\PDB\DSSP.py", line 231, in dssp_dict_from_pdb_file
    p = subprocess.Popen(
  File "C:\ProgramData\Miniconda3\lib\subprocess.py", line 947, in __init__
    self._execute_child(args, executable, preexec_fn, close_fds,
  File "C:\ProgramData\Miniconda3\lib\subprocess.py", line 1416, in _execute_child
    hp, ht, pid, tid = _winapi.CreateProcess(executable, args,
FileNotFoundError: [WinError 2] The system cannot find the file specified

Process finished with exit code 1

Why am I unable to execute DSSP algorithm from BioPython?

  • $\begingroup$ Just in the offchange, you install the DSSP binary (swift.cmbi.umcn.nl/gv/dssp) as described in the BioPython documentation, right? $\endgroup$ Sep 20, 2021 at 13:20
  • $\begingroup$ @MatteoFerla, Yes. Check the newly added screenshot. $\endgroup$
    – user366312
    Sep 20, 2021 at 14:37
  • 1
    $\begingroup$ Installing biopython does not magically install DSSP. $\endgroup$
    – Devon Ryan
    Sep 20, 2021 at 17:31

2 Answers 2


This looks like a python problem and not a “biopython”problem.

Check your file structures. Try giving a full path for 16pk.pdb

These might help. https://stackoverflow.com/questions/17658856/why-am-i-getting-a-filenotfounderror


  • $\begingroup$ Up-voted to offset a highly incorrect down-vote. $\endgroup$
    – Devon Ryan
    Sep 20, 2021 at 17:31

Ok so this might not provide a solution, but here's a couple things someone might find useful;

  • First, Biopython does not automatically contain DSSP, which you have to download as mentioned in the comments below (from here swift.cmbi.umcn.nl/gv/dssp)
  • Secondly, DSSP within Biopython, for whatever reason, accepts the path to the file, not the file itself. I see you have that correctly (dssp = DSSP(model, "16pk.pdb")), but just pointing it ou
  • Third, DSSP originally had dssp executable, but the newer version has mkdssp executable, so you might need to do dssp = DSSP(model, "16pk.pdb", dssp="mkdssp"), so it knows what to associate it with. This was the problem I had, because without specifying the dssp, it is not able to launch DSSP.

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