The OEGetFPOverlap function provides access to the fragments of two molecules that are considered equivalent based on a specific fingerprint type. This means that the returned fragment-pairs set the same bit “on” when fingerprints are generated. The following example shows how to retrieve the common five bond-length patterns of two molecules.
Listing 18: Example of accessing common patterns based on a fingerprint
pmol = oechem.OEGraphMol() oechem.OESmilesToMol(pmol, "c1cnc2c(c1)CC(CC2O)CF") tmol = oechem.OEGraphMol() oechem.OESmilesToMol(tmol, "c1cc2c(cc1)CC(CCl)CC2N") fptype = oegraphsim.OEGetFPType("Tree,ver=2.0.0,size=4096,bonds=5-5,atype=AtmNum|HvyDeg|EqHalo,btype=Order") for idx, match in enumerate(oegraphsim.OEGetFPOverlap(pmol, tmol, fptype)): ostring = "match %2d: " % (idx + 1) for mpair in match.GetAtoms(): p = mpair.pattern t = mpair.target ostring += "%d%s-%d%s " % (p.GetIdx(), oechem.OEGetAtomicSymbol(p.GetAtomicNum()), t.GetIdx(), oechem.OEGetAtomicSymbol(t.GetAtomicNum())) print(ostring)
The first three matches returned by the Listing 18 are depicted in the next table. The output of code is the following:
match 1: 3C-2C 9C-11C 4C-3C 8C-10C 7C-7C 11C-8C match 2: 3C-2C 4C-3C 5C-4C 6C-6C 7C-7C 8C-8C match 3: 3C-2C 4C-3C 5C-4C 6C-6C 7C-7C 8C-10C match 4: 3C-2C 4C-3C 5C-4C 6C-6C 7C-7C 11C-8C match 5: 3C-2C 4C-3C 5C-4C 6C-6C 7C-7C 11C-10C match 6: 3C-2C 9C-11C 4C-3C 6C-6C 7C-7C 11C-8C ... truncated ...
Even though the OEGetFPOverlap function returns an iterator of OEMatchBase objects, they are not matches in the traditional sense, i.e. the atom-pair and bond-pair correspondences between the pattern and the target atoms and bonds are not guaranteed. See example depicted below.
The OEGetFPOverlap can be used to visualize molecule similarity based on a given fingerprint type. See more details in: