Improve workflow for ChEMBL database test

[flange-ipb]

Related to #51.

Move workflow to a separate repository:

• TUCAN-nest/ChEMBL-test

Separate Snakemake rules and Python code:

At the moment the Snakemake file is polluted with Python code for (a) SDFile creation from the SQLite database and (b) test execution.

• move (a) and (b) into separate Python modules.

Create snapshot:

At the moment a workflow run creates a log file with ChEMBL IDs that fail test_invariance.

I'm proposing to let the workflow run create a "snapshot file" with the TUCAN strings and test results. This snapshot file should be versionable (text format) and should be added to the repository. CSV seems to be a wise choice and a csv writer is included in Python's standard library. The csv file should look like this:

chembl_id,tucan,passed_test_invariance,passed_test_sumformula,passed_test_roundtrip_molfile_graph_tucan_graph_tucan_graph
CHEMBL6329,"C17H12ClN3O3/...",true,true,true
...

I'm expecting a file size of several tens of megabytes.

Further tasks:

• concatenate snapshot files from all chunks ordered by the chunk number (find like it is used right now does not give a reproducible order)
• document how a SQLite database can be created from the csv snapshot file

Make tests reusable:

test_invariance in the Snakemake file is more or less a duplicate of test_invariance in TUCAN's tests.

In order to improve reusability, most of test_invariance's implementation should be moved from TUCAN's test suite to a test module in the tucan package (i.e. into tucan/test_utils.py). The Snakemake workflow can then import test_invariance from tucan.test_utils and catch the AssertionError.

Add more tests:

• Check the sum formula from the TUCAN string against the sum formula from the ChEMBL compound (column full_molformula of table compound_properties). The sum formula can be written into the SDFile like it's already done with the ChEMBL ID. This aims to test the addition of implicit hydrogens, which is done using RDKit at the moment.
• roundtrip test Molfile -> graph -> TUCAN -> graph -> TUCAN -> graph

Bijection test:

TUCAN's test_bijection is supposed to show that all (different) compounds in the test set have different TUCAN strings from each other. This should also be checked for the ChEMBL dataset, but the test implementation will be different:

• create a SQLite database from the csv snapshot
• add an index on the tucan column
• find TUCAN string duplicates: SELECT COUNT(tucan), tucan FROM table GROUP BY tucan HAVING COUNT(tucan) > 1 (thanks @fbroda)

Tasks:

• automate (shell or Python script)

Licensing:

• The ChEMBL data is licensed under CC-BY-SA 3.0. I think the snapshot file counts as "derivative work", so I will license it with CC-BY-SA 4.0 (CC-BY-SA 3.0 allows upwards-compatibility). GPLv3 is not a compatible license for CC-BY-SA 3.0.
• Code (Snakemake file, Python modules) will be licensed with GPLv3.

Tasks:

• add LICENSE file (CC-BY-SA 4.0) next to the snapshot file
• add attribution via a readme next to the snapshot file
• add GPLv3

Other tasks:

• upgrade to ChEMBL version 31

[schatzsc]

Maybe add something like TUCAN-nest/ChEMBL-test to indicate it is not a ChEMBL version itself that is worked up?

[flange-ipb]

I'm expecting a file size of several tens of megabytes.

Well, the snapshot file has a size of about one gigabyte and GitHub refuses the upload (limit is 25 MB). I uploaded it to the repo using git lfs (limit is 2 GB for GitHub).

[flange-ipb]

Analysis

test_permutation_invariance

No fails.

test_sumformula

Compare sum formulas from the TUCAN string and from the ChEMBL compound (without charge annotations).

55 fails:

ChEMBL ID	sum formula from TUCAN	sum formula from ChEMBL
CHEMBL42403	BH3O3	H3BO3
CHEMBL542171	Cl2H6N2	H6Cl2N2
CHEMBL542448	ClH4NO	H4ClNO
CHEMBL1161633	ClHO3	HClO3
CHEMBL1161634	ClHO4	HClO4
CHEMBL1161635	BrHO3	HBrO3
CHEMBL1200706	AlH3O3	H3AlO3
CHEMBL1200939	ClH4N	H4ClN
CHEMBL1207889	FHO3S	HFO3S
CHEMBL1231052	AsH3	H3As
CHEMBL1231461	BrH	HBr
CHEMBL1231821	ClH	HCl
CHEMBL1232767	FH	HF
CHEMBL1236189	AsH3O3	H3AsO3
CHEMBL1616046	ClHO	HClO
CHEMBL1879693	ClH4NO4	H4ClNO4
CHEMBL1906899	ClHO2	HClO2
CHEMBL1909080	Cl2H12O6Sr	H12Cl2O6Sr
CHEMBL1909222	AsHO2	HAsO2
CHEMBL1909275	FH	HF
CHEMBL2097011	B4H2O7	H2B4O7
CHEMBL2104840	Cl2H3K2MgNa3O12P2S	H3Cl2K2MgNa3O12P2S
CHEMBL2106388	CaH2O2	H2CaO2
CHEMBL2107006	CaHNaO2	HCaNaO2
CHEMBL2107567	CaHO4P	HCaO4P
CHEMBL2140344	BF3H4O2	H4BF3O2
CHEMBL2146121	CaH2	H2Ca
CHEMBL2218895	CaH4O4P2	H4CaO4P2
CHEMBL2218916	Ca5HO13P3	HCa5O13P3
CHEMBL2365415	As3H5O7	H5As3O7
CHEMBL2374288	AsH3O4	H3AsO4
CHEMBL2448495	As3H2Na3O7	H2As3Na3O7
CHEMBL3184656	BeH8O8S	H8BeO8S
CHEMBL3185229	Cl2H12MgO6	H12Cl2MgO6
CHEMBL3185957	BaCl2H4O2	H4BaCl2O2
CHEMBL3186904	BF4H	HBF4
CHEMBL3188962	AsH15Na2O11	H15AsNa2O11
CHEMBL3707333	B2H4Na2O8	H4B2Na2O8
CHEMBL3707334	B2H4O8	H4B2O8
CHEMBL3707387	Cl4H2O11	H2Cl4O11
CHEMBL3833310	AlH5O4	H5AlO4
CHEMBL3833314	AlCl3H12O6	H12AlCl3O6
CHEMBL3833322	Al2H2MgO13Si4	H2Al2MgO13Si4
CHEMBL3833332	Al2H2O13S3	H2Al2O13S3
CHEMBL3833350	Al5H33Mg10O40S2	H33Al5Mg10O40S2
CHEMBL3833365	Al2H4O9Si2	H4Al2O9Si2
CHEMBL3833375	B4H20Na2O17	H20B4Na2O17
CHEMBL3833408	Al5H31Mg10O39S2	H31Al5Mg10O39S2
CHEMBL3833411	B4H2O7	H2B4O7
CHEMBL3989874	BaCaH4O4	H4BaCaO4
CHEMBL4297206	AgFH6N2	H6AgFN2
CHEMBL4298415	BrH	HBr
CHEMBL4298435	AsF6H	HAsF6
CHEMBL4299960	Cl4H4O10	H4Cl4O10
CHEMBL4450513	AgHO	HAgO

It seems ChEMBL annotates hydrogens first if carbon is absent.

test_roundtrip_molfile_graph_tucan_graph_tucan_graph (serializer-parser roundtrip)

No fails.

Bijection test

171008 fails.
As far as I can tell, most of them are stereoisomers. For instance

• CHEMBL1573853,
• CHEMBL1716183,
• CHEMBL1882433,
• CHEMBL1883192,
• CHEMBL1884515,
• CHEMBL1906279 and
• CHEMBL2134455

all have the same TUCAN string (and identical InChIKey main layer).
Nothing to worry about at the moment.

[schatzsc]

Really excellent work, absolutely love it!

About the bijection test, you mention that "most of them are stereoisomers" - is there a way to quantify this and in particular single out and show the ChEMBL codes for those which are not stereoisomers?

Other than that, works as expected, since stereoisomers are not covered by definition at the moment.

[flange-ipb]

@schatzsc

in particular single out and show the ChEMBL codes for those which are not stereoisomers?

I guess with the first layer of the InChIKey (first 14 characters) we should be able to detect this.

Thus, I just added the following to the analysis pipeline:

• (1) find all compounds with duplicate TUCAN strings (= what I called bijection test previously)

and among those

• (2) find all compounds with different InChIKey first layer.

(1) gives 171008 compounds, (2) reduces this to 64 compounds.

Table of compounds: (that's the same data like in the csv file)

Duplicates	TUCAN string
CHEMBL1200471 (OTPSWLRZXRHDNX-UHFFFAOYSA-L) CHEMBL3392049 (PICXIOQBANWBIZ-UHFFFAOYSA-N)	C10H8N2O2S2Zn/(1-9)(2-10)(3-11)(4-12)(5-13)(6-14)(7-15)(8-16)(9-11)(9-13)(10-12)(10-14)(11-15)(12-16)(13-17)(14-18)(15-19)(16-20)(17-19)(17-23)(18-20)(18-24)(19-21)(20-22)
CHEMBL74469 (INFDPOAKFNIJBF-UHFFFAOYSA-N) CHEMBL1451731 (CGIXVVWWIDFCNE-UHFFFAOYSA-N)	C12H14N2/(1-15)(2-16)(3-17)(4-18)(5-21)(6-21)(7-21)(8-22)(9-22)(10-22)(11-23)(12-24)(13-25)(14-26)(15-19)(15-23)(16-19)(16-24)(17-20)(17-25)(18-20)(18-26)(19-20)(21-27)(22-28)(23-27)(24-27)(25-28)(26-28)
CHEMBL1569487 (WLHQHAUOOXYABV-UHFFFAOYSA-N) CHEMBL3188235 (GTASRFITTBVXRX-UHFFFAOYSA-N)	C13H10ClN3O4S2/(1-11)(2-12)(3-13)(4-14)(5-15)(6-15)(7-15)(8-16)(9-25)(10-28)(11-12)(11-13)(12-16)(13-18)(14-22)(14-23)(15-26)(16-24)(17-19)(17-20)(17-26)(18-24)(18-25)(19-21)(19-28)(20-25)(20-27)(21-22)(21-31)(22-32)(23-31)(23-33)(26-32)(29-32)(30-32)
CHEMBL302795 (LZNWYQJJBLGYLT-UHFFFAOYSA-N) CHEMBL3188633 (MHLVRGMNJBUIRL-UHFFFAOYSA-N)	C13H11N3O4S2/(1-12)(2-13)(3-14)(4-15)(5-16)(6-16)(7-16)(8-17)(9-22)(10-26)(11-29)(12-13)(12-14)(13-17)(14-19)(15-22)(15-24)(16-27)(17-25)(18-20)(18-21)(18-27)(19-25)(19-26)(20-23)(20-29)(21-26)(21-28)(22-32)(23-24)(23-32)(24-33)(27-33)(30-33)(31-33)
CHEMBL599 (ZRVUJXDFFKFLMG-UHFFFAOYSA-N) CHEMBL1741042 (JJMWPUUMNOUPNB-UHFFFAOYSA-N)	C14H13N3O4S2/(1-14)(2-14)(3-14)(4-15)(5-16)(6-17)(7-18)(8-20)(9-20)(10-20)(11-21)(12-29)(13-32)(14-25)(15-16)(15-17)(16-18)(17-19)(18-26)(19-23)(19-26)(20-30)(21-25)(21-28)(22-23)(22-24)(22-30)(23-32)(24-29)(24-31)(25-35)(26-36)(27-28)(27-29)(27-35)(30-36)(33-36)(34-36)
CHEMBL53292 (YYUAYBYLJSNDCX-UHFFFAOYSA-N) CHEMBL1898455 (RSBXRGZKRGVKGF-UHFFFAOYSA-N)	C14H13N3O5S/(1-14)(2-14)(3-14)(4-15)(5-16)(6-17)(7-18)(8-19)(9-21)(10-21)(11-21)(12-28)(13-32)(14-25)(15-16)(15-17)(16-19)(17-20)(18-23)(18-25)(19-27)(20-24)(20-27)(21-30)(22-24)(22-26)(22-30)(23-28)(23-29)(24-32)(25-33)(26-28)(26-31)(27-36)(29-33)(30-36)(34-36)(35-36)
CHEMBL1091115 (NALREUIWICQLPS-UHFFFAOYSA-N) CHEMBL3330735 (PGWTYMLATMNCCZ-UHFFFAOYSA-M)	C14H14ClN3S/(1-15)(2-16)(3-17)(4-18)(5-19)(6-20)(7-21)(8-21)(9-21)(10-22)(11-22)(12-22)(13-29)(14-29)(15-16)(15-23)(16-24)(17-18)(17-25)(18-26)(19-23)(19-27)(20-26)(20-28)(21-31)(22-31)(23-29)(24-27)(24-30)(25-28)(25-30)(26-31)(27-32)(28-32)
CHEMBL1199277 (HMYISFASHDWPMO-UHFFFAOYSA-O) CHEMBL3558280 (FXONXBFTEMLSRZ-UHFFFAOYSA-N)	C14H14N3S/(1-15)(2-16)(3-17)(4-18)(5-19)(6-20)(7-21)(8-21)(9-21)(10-22)(11-22)(12-22)(13-29)(14-29)(15-16)(15-23)(16-24)(17-18)(17-25)(18-26)(19-23)(19-27)(20-26)(20-28)(21-31)(22-31)(23-29)(24-27)(24-30)(25-28)(25-30)(26-31)(27-32)(28-32)
CHEMBL2104833 (VCSAHSDZAKGXAT-AFEZEDKISA-M) CHEMBL2282011 (WUHOMZPXRJWWDW-UHFFFAOYSA-M)	C14H8ClN2NaO3S/(1-9)(2-10)(3-11)(4-12)(5-13)(6-20)(7-23)(8-23)(9-12)(9-16)(10-11)(10-20)(11-21)(12-22)(13-14)(13-22)(14-15)(14-16)(15-17)(15-18)(16-24)(17-21)(17-25)(18-24)(18-26)(19-23)(19-24)(19-27)(20-29)(21-29)(22-30)
CHEMBL428064 (CYSOFAOLQAYKGU-UHFFFAOYSA-N) CHEMBL1589921 (LKDGTXMRXOKPFZ-UHFFFAOYSA-N)	C15H10N2O2S/(1-11)(2-12)(3-13)(4-14)(5-15)(6-16)(7-17)(8-18)(9-22)(10-27)(11-12)(11-16)(12-18)(13-15)(13-19)(14-17)(14-19)(15-20)(16-21)(17-22)(18-25)(19-23)(20-21)(20-24)(21-25)(22-26)(23-24)(23-26)(24-27)(25-30)(27-30)(28-30)(29-30)
CHEMBL527 (QYSPLQLAKJAUJT-UHFFFAOYSA-N) CHEMBL1518938 (IAPMPNKHZPZVQU-UHFFFAOYSA-N)	C15H13N3O4S/(1-14)(2-15)(3-16)(4-17)(5-18)(6-19)(7-20)(8-22)(9-22)(10-22)(11-23)(12-30)(13-33)(14-16)(14-17)(15-18)(15-19)(16-20)(17-21)(18-23)(19-25)(20-28)(21-26)(21-28)(22-31)(23-29)(24-26)(24-27)(24-31)(25-29)(25-30)(26-33)(27-30)(27-32)(28-36)(31-36)(34-36)(35-36)
CHEMBL562639 (GEDVVYWLPUPJJZ-UHFFFAOYSA-N) CHEMBL1790006 (HNONEKILPDHFOL-UHFFFAOYSA-M)	C15H16ClN3S/(1-17)(2-17)(3-17)(4-18)(5-19)(6-20)(7-21)(8-22)(9-24)(10-24)(11-24)(12-25)(13-25)(14-25)(15-32)(16-32)(17-23)(18-19)(18-27)(19-29)(20-23)(20-28)(21-26)(21-31)(22-29)(22-30)(23-26)(24-34)(25-34)(26-32)(27-30)(27-33)(28-31)(28-33)(29-34)(30-35)(31-35)
CHEMBL1817784 (DNDJEIWCTMMZBX-UHFFFAOYSA-N) CHEMBL3330736 (KFZNPGQYVZZSNV-UHFFFAOYSA-M)	C15H16ClN3S/(1-17)(2-18)(3-19)(4-20)(5-21)(6-22)(7-23)(8-23)(9-23)(10-24)(11-24)(12-24)(13-25)(14-25)(15-25)(16-33)(17-19)(17-26)(18-20)(18-27)(19-28)(20-29)(21-28)(21-30)(22-29)(22-31)(23-33)(24-34)(25-34)(26-30)(26-32)(27-31)(27-32)(28-33)(29-34)(30-35)(31-35)
CHEMBL1197206 (KZEUBCUXBNEMSQ-UHFFFAOYSA-O) CHEMBL1622638 (RQNADZJRELIICT-UHFFFAOYSA-N)	C15H16N3S/(1-17)(2-17)(3-17)(4-18)(5-19)(6-20)(7-21)(8-22)(9-24)(10-24)(11-24)(12-25)(13-25)(14-25)(15-32)(16-32)(17-23)(18-19)(18-27)(19-29)(20-23)(20-28)(21-26)(21-31)(22-29)(22-30)(23-26)(24-34)(25-34)(26-32)(27-30)(27-33)(28-31)(28-33)(29-34)(30-35)(31-35)
CHEMBL1852066 (KKGWEPLBCABCDN-UHFFFAOYSA-O) CHEMBL3558304 (VBFJMDUNUIVOMH-UHFFFAOYSA-N)	C15H16N3S/(1-17)(2-18)(3-19)(4-20)(5-21)(6-22)(7-23)(8-23)(9-23)(10-24)(11-24)(12-24)(13-25)(14-25)(15-25)(16-33)(17-19)(17-26)(18-20)(18-27)(19-28)(20-29)(21-28)(21-30)(22-29)(22-31)(23-33)(24-34)(25-34)(26-30)(26-32)(27-31)(27-32)(28-33)(29-34)(30-35)(31-35)
CHEMBL1729471 (MXLFKQWACADBHE-UHFFFAOYSA-N) CHEMBL3913079 (KZLRTHGLORNBHC-UHFFFAOYSA-N)	C16H12N2O2S/(1-13)(2-13)(3-13)(4-14)(5-15)(6-16)(7-17)(8-18)(9-19)(10-20)(11-21)(12-30)(13-25)(14-15)(14-19)(15-21)(16-18)(16-22)(17-20)(17-22)(18-23)(19-24)(20-25)(21-28)(22-26)(23-24)(23-27)(24-28)(25-29)(26-27)(26-29)(27-30)(28-33)(30-33)(31-33)(32-33)
CHEMBL273148 (MXKZFNJSAXLWNC-UHFFFAOYSA-N) CHEMBL1712499 (ZEPLLJACXSUGNZ-UHFFFAOYSA-N)	C17H11F3N2O2S/(1-12)(2-12)(3-12)(4-13)(5-14)(6-15)(7-16)(8-17)(9-18)(10-19)(11-30)(12-24)(13-15)(13-20)(14-18)(14-20)(15-21)(16-19)(16-22)(17-22)(17-23)(18-24)(19-28)(20-25)(21-23)(21-26)(22-27)(23-28)(24-29)(25-26)(25-29)(26-30)(27-33)(27-34)(27-35)(28-36)(30-36)(31-36)(32-36)
CHEMBL188744 (ZVHVJEWJNSDXDB-UHFFFAOYSA-N) CHEMBL2005075 (CABFNLMCQJOTMT-UHFFFAOYSA-O)	C18H17N7O/(1-18)(2-18)(3-18)(4-19)(5-20)(6-21)(7-22)(8-23)(9-24)(10-25)(11-26)(12-27)(13-27)(14-36)(15-36)(16-37)(17-37)(18-27)(19-20)(19-21)(20-24)(21-25)(22-23)(22-28)(23-31)(24-32)(25-32)(26-28)(26-33)(27-30)(28-29)(29-30)(29-34)(30-38)(31-33)(31-40)(32-41)(33-42)(34-36)(34-39)(35-37)(35-38)(35-39)(40-41)(41-42)(42-43)
CHEMBL2105246 (DMHQLXUFCQSQQQ-JZJYNLBNSA-N) CHEMBL3989800 (OWFUPROYPKGHMH-UHFFFAOYSA-N)	C18H18N4O2/(1-19)(2-19)(3-19)(4-20)(5-21)(6-22)(7-23)(8-24)(9-25)(10-26)(11-27)(12-28)(13-29)(14-30)(15-30)(16-32)(17-34)(18-38)(19-34)(20-22)(20-23)(21-24)(21-25)(22-26)(23-27)(24-28)(25-29)(26-31)(27-31)(28-33)(29-33)(30-31)(30-34)(32-35)(32-39)(33-38)(34-39)(35-37)(35-42)(36-37)(36-38)(36-41)(39-40)(40-42)
CHEMBL1200879 (KYITYFHKDODNCQ-UHFFFAOYSA-M) CHEMBL2028193 (INUBUXBVYNRDGP-UHFFFAOYSA-M)	C19H15NaO4/(1-16)(2-16)(3-16)(4-17)(5-18)(6-19)(7-20)(8-21)(9-22)(10-23)(11-24)(12-25)(13-26)(14-26)(15-30)(16-31)(17-18)(17-19)(18-22)(19-23)(20-21)(20-24)(21-25)(22-27)(23-27)(24-28)(25-33)(26-30)(26-31)(27-30)(28-32)(28-33)(29-30)(29-32)(29-34)(31-35)(32-36)(33-38)(34-37)(34-38)
CHEMBL1178103 (DIGXMFZQXQUVMR-UHFFFAOYSA-N) CHEMBL1627264 (PLMIUUBYGDLUDD-UHFFFAOYSA-N)	C21H23NO5S/(1-24)(2-24)(3-24)(4-25)(5-26)(6-27)(7-28)(8-29)(9-30)(10-30)(11-31)(12-31)(13-32)(14-32)(15-33)(16-33)(17-34)(18-34)(19-43)(20-43)(21-43)(22-45)(23-48)(24-30)(25-27)(25-38)(26-36)(26-38)(27-40)(28-35)(28-44)(29-37)(29-44)(30-31)(31-32)(32-33)(33-34)(34-35)(35-41)(36-39)(36-40)(37-39)(37-41)(38-42)(39-46)(40-49)(41-49)(42-47)(42-48)(43-51)(44-51)(45-51)(50-51)
CHEMBL90073 (FPQMLJDRTAEFLR-UHFFFAOYSA-N) CHEMBL110934 (QKVZLTHLJDEDFA-IMVLJIQESA-N)	C22H22N6O2S/(1-23)(2-24)(3-25)(4-26)(5-27)(6-28)(7-29)(8-30)(9-31)(10-32)(11-33)(12-36)(13-36)(14-36)(15-37)(16-37)(17-37)(18-44)(19-44)(20-44)(21-46)(22-50)(23-24)(23-25)(24-27)(25-34)(26-30)(26-35)(27-38)(28-31)(28-40)(29-32)(29-40)(30-42)(31-43)(32-43)(33-39)(33-42)(34-38)(34-41)(35-39)(35-41)(36-48)(37-48)(38-45)(39-45)(40-46)(41-46)(42-47)(43-50)(44-53)(47-49)(48-49)(50-53)(51-53)(52-53)
CHEMBL45260 (WHQCODQJWHWKCA-UHFFFAOYSA-N) CHEMBL42192 (PJZWENDBSVLVEB-UHFFFAOYSA-N)	C34H40N4/(1-41)(2-42)(3-43)(4-44)(5-45)(6-46)(7-47)(8-48)(9-49)(10-50)(11-51)(12-52)(13-53)(14-54)(15-55)(16-56)(17-63)(18-63)(19-63)(20-64)(21-64)(22-64)(23-65)(24-65)(25-65)(26-66)(27-66)(28-66)(29-67)(30-67)(31-67)(32-68)(33-68)(34-68)(35-69)(36-69)(37-69)(38-70)(39-70)(40-70)(41-49)(41-57)(42-50)(42-57)(43-51)(43-58)(44-52)(44-58)(45-53)(45-59)(46-54)(46-59)(47-55)(47-60)(48-56)(48-60)(49-71)(50-71)(51-72)(52-72)(53-73)(54-73)(55-74)(56-74)(57-61)(58-61)(59-62)(60-62)(61-62)(63-75)(64-75)(65-76)(66-76)(67-77)(68-77)(69-78)(70-78)(71-75)(72-76)(73-77)(74-78)
CHEMBL2105351 (XNRNJIIJLOFJEK-UHFFFAOYSA-N) CHEMBL2364542 (WNGMMIYXPIAYOB-UHFFFAOYSA-M)	C5H4NNaOS/(1-5)(2-6)(3-7)(4-8)(5-6)(5-7)(6-8)(7-9)(8-10)(9-10)(9-13)(10-11)
CHEMBL357626 (MIJOCOSWJQYXGU-TZKMECQKSA-N) CHEMBL1627232 (PSCDTFAJGFDXAO-TZKMECQKSA-N)	C6H11NO6S/(1-12)(2-12)(3-16)(4-16)(5-16)(6-17)(7-17)(8-18)(9-21)(10-22)(11-23)(12-13)(12-14)(13-15)(13-17)(13-21)(14-19)(14-22)(15-20)(15-23)(16-25)(17-25)(18-25)(24-25)
CHEMBL842 (JBMKAUGHUNFTOL-UHFFFAOYSA-N) CHEMBL3392493 (MRLXNACLEKEMCQ-UHFFFAOYSA-N)	C7H6ClN3O4S2/(1-7)(2-8)(3-10)(4-15)(5-15)(6-16)(7-11)(7-12)(8-9)(8-13)(9-11)(9-14)(10-14)(10-16)(11-22)(12-13)(12-21)(13-23)(15-21)(16-22)(17-21)(18-21)(19-22)(20-22)
CHEMBL1514931 (ZVBIRPKGWOVBLG-UHFFFAOYSA-N) CHEMBL1596271 (QVADSMGRZHVGPL-UHFFFAOYSA-M)	C8H7N2NaO3S/(1-8)(2-9)(3-10)(4-11)(5-15)(6-15)(7-17)(8-9)(8-10)(9-11)(10-12)(11-14)(12-13)(12-14)(13-15)(13-16)(14-18)(15-22)(16-18)(17-22)(19-22)(20-22)
CHEMBL2107528 (ZPNRBQVNNIDJHX-UHFFFAOYSA-M) CHEMBL3186518 (DSOWAKKSGYUMTF-GZOLSCHFSA-M)	C8H7NaO4/(1-8)(2-8)(3-8)(4-9)(5-9)(6-9)(7-10)(8-12)(9-14)(10-13)(10-14)(11-12)(11-13)(11-15)(12-16)(13-17)(14-19)(15-18)(15-19)
CHEMBL1741516 (AGQSEIGTBQIVBF-UHFFFAOYSA-N) CHEMBL1989025 (PZUHHXFIMAEXGO-UHFFFAOYSA-N)	C9H8N2O2/(1-9)(2-9)(3-9)(4-10)(5-11)(6-12)(7-13)(8-14)(9-15)(10-11)(10-12)(11-13)(12-16)(13-17)(14-15)(14-18)(15-19)(16-17)(16-18)(17-19)(18-20)(19-21)
CHEMBL1644028 (VGTPCRGMBIAPIM-UHFFFAOYSA-M) CHEMBL2207072 (RROSXLCQOOGZBR-UHFFFAOYSA-N)	CNNaS/(1-2)(1-4)
CHEMBL448089 (IBJRLHARKKQREK-UHFFFAOYSA-M) CHEMBL2069541 (YTCRRZPPDGMMBV-UHFFFAOYSA-N)	CNNaSe/(1-2)(1-4)
CHEMBL1201279 (HCHKCACWOHOZIP-UHFFFAOYSA-N) CHEMBL1236970 (PTFCDOFLOPIGGS-UHFFFAOYSA-N)	Zn/

[schatzsc]

I did not manage to check all of the structural pairs individually, but the problem seems to be related to tautomer formation and is not an issue of TUCAN but rather of InChI, as all the structures I looked at appear to be the same and should have identical TUCAn strings ;-)