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errors,Structures not same size

Open oyileo opened this issue 1 year ago • 2 comments

pdb: 8xgo 8xgn

CsFAOMT.zip

oyileo avatar Jan 15 '24 09:01 oyileo

Will take a look (reference to #102 )

charnley avatar Jan 15 '24 09:01 charnley

@oyileo Because the two structures differ in atom count (either in the form shared by you, or neglecting hydrogen atoms), calculate_rmsd is going to report "structures of different size", and exit.

For one, 8gxn.pdb is about a structure model including hydrogen atoms. Counting the atoms with openbabel and wc -l*:

$ obabel 8gxn.pdb -oxyz | wc -l
1 molecule converted
3934
$ obabel 8gxn.pdb -oxyz | grep "H" -c
1 molecule converted
1846
# tentatively delete hydrogen atoms present
$ obabel 8gxn.pdb -oxyz -d | wc -l
1 molecule converted
2088
$ obabel 8gxn.pdb -oxyz -d | grep "H" -c
1 molecule converted
0

For two, 8gxo.pdb is about a model without any hydrogen atoms. Its number of atoms differs to the one in 8gxn.pdb, and a deletion of hydrogens in 8gxn.pdb alone is not sufficient for an analysis by calculate_rmsd:

$ obabel 8gxo.pdb -oxyz | wc -l
==============================
*** Open Babel Warning  in PerceiveBondOrders
  Failed to kekulize aromatic bonds in OBMol::PerceiveBondOrders (title is 8gxo.pdb)

1 molecule converted
4001
$ obabel 8gxo.pdb -oxyz | grep "H" -c
==============================
*** Open Babel Warning  in PerceiveBondOrders
  Failed to kekulize aromatic bonds in OBMol::PerceiveBondOrders (title is 8gxo.pdb)

1 molecule converted
0

* The count is off by two (the line about the number of atoms, the line of optional comments), but this systematic error will be present in both checks.

nbehrnd avatar Jan 15 '24 10:01 nbehrnd