Dear Chimera Users, First Happy New Year to you and your families! I am trying to perform protein-ligand docking using UCSF Chimera 1.16v installed on my iMAC Big Sur. Using the pdb of the receptor and mol2 of the ligand (that I have already tested with VINA 1.2.3!) I got the following error: Model 1 (receptor.pdb) appears to be a protein without secondary structure assignments. Automatically computing assignments using 'ksdssp' and parameter values: energy cutoff -0.5 minimum helix length 3 minimum strand length 3 Use command 'help ksdssp' for more information. No SEQRES records for receptor.pdb (#1) chain A; guessing terminii instead Chain-initial residues that are actual N terminii: #1 SER 1.A Chain-initial residues that are not actual N terminii: Chain-final residues that are actual C terminii: Chain-final residues that are not actual C terminii: #1 THR 304.A 278 hydrogen bonds Removing spurious proton from 'C' of #1 THR 304.A Hydrogens added Wrote test.receptor.pdb into /Users/gleb/Desktop/docking_tuto adding gasteiger charges to peptide Traceback (most recent call last): File "/Applications/Chimera.app/Contents/Resources/share/vina/ws.py", line 395, in prepareReceptor execfile(scriptPath, d) File "/Applications/Chimera.app/Contents/Resources/lib/python2.7/site-packages/AutoDockTools/Utilities24/prepare_receptor4.py", line 172, in <module> delete_single_nonstd_residues=delete_single_nonstd_residues) File "/Applications/Chimera.app/Contents/Resources/lib/python2.7/site-packages/AutoDockTools/MoleculePreparation.py", line 533, in __init__ version=version, delete_single_nonstd_residues=delete_single_nonstd_residues) File "/Applications/Chimera.app/Contents/Resources/lib/python2.7/site-packages/AutoDockTools/MoleculePreparation.py", line 140, in __init__ self.addCharges(mol, charges_to_add) File "/Applications/Chimera.app/Contents/Resources/lib/python2.7/site-packages/AutoDockTools/MoleculePreparation.py", line 226, in addCharges chargeCalculator.addCharges(mol.allAtoms) File "/Applications/Chimera.app/Contents/Resources/lib/python2.7/site-packages/MolKit/chargeCalculator.py", line 80, in addCharges babel.assignHybridization(atoms) File "/Applications/Chimera.app/Contents/Resources/lib/python2.7/site-packages/PyBabel/atomTypes.py", line 127, in assignHybridization a.babel_atomic_number = self.get_atomic_number(a.babel_type) File "/Applications/Chimera.app/Contents/Resources/lib/python2.7/site-packages/PyBabel/atomTypes.py", line 103, in get_atomic_number (name,_name) ) ValueError: Could not find atomic number for Hn Hn Receptor preparation for AutoDock Vina failed; please look in Reply Log to see error messages.cannot prepare receptor for AutoDock Vina; please look in Reply Log and/or run Chimera with --debug flag to see errors. So here are my questions: 1) May this error be related to the version of OSX installed on my imac (I can not run MGL tools on the Big Sur for instance) ?? 2) Alternatively may I use the ADT scripts integrated in the Chimera like prepare_receptor4.py for my scripting purposes (outside of the UCSF Chimera) on the same iMAC machine ? Many thanks in advance! Cheers Enrico