X-group (possible homology)

219 Cysteine proteinases-like

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Ligands and drugs

7,757

Member domains

2,040

with ligand contacts (≤ 4 Å)

26.3% of members

1,700

with DrugDomain annotations

21.9% of members

942

with a DrugBank compound

12.1% of members

Aggregated over all current member domains of this group. Drug annotations come from DrugDomain; buffers and crystallization additives are excluded from the tables below.

Chemical profile

ClassyFire chemical superclasses of the ligands bound by this X-group's proteins, from DrugDomain annotations.

214

Proteins with classified ligands

Superclasses bound (of 23)

9.6

Superclasses per 20 proteins

broader than 89% of the 256 X-groups with enough proteins to compare (median 7.6)

The raw number of superclasses rises with the number of proteins sampled; the per-20 value compares X-groups at equal depth.

Superclass	Proteins	Expected	Ratio	Significance
Organic nitrogen compounds	32	6.7	4.75×	q < 0.0001
Organic acids and derivatives	60	32.7	1.84×	q < 0.0001
Benzenoids	27	15.4	1.75×	q = 9.8e-3
Homogeneous non-metal compounds	73	45.4	1.61×	q < 0.0001
Homogeneous metal compounds	106	103.6	1.02×	q = 0.85
Organic oxygen compounds	30	42.0	0.71×	q = 0.06
Organoheterocyclic compounds	22	32.5	0.68×	q = 0.07
Lipids and lipid-like molecules	6	23.5	0.26×	q < 0.0001
Nucleosides, nucleotides, and analogues	12	58.3	0.21×	q < 0.0001
Organohalogen compounds	4	0.6	6.66×	not tested
Organosulfur compounds	11	4.3	2.53×	not tested
Phenylpropanoids and polyketides	7	4.4	1.59×	not tested
Alkaloids and derivatives	1	0.7	1.39×	not tested
Mixed metal/non-metal compounds	1	4.4	0.23×	not tested

enriched (q < 0.05)depleted (q < 0.05)not significantnot tested (expected < 5)

Unit: a protein (UniProt accession) with a ligand-binding domain in this X-group, counted once per superclass. Expected counts use each superclass's frequency across all ligand-binding X-groups; significance is Fisher's exact test with Benjamini–Hochberg correction. Buffers and crystallization additives are excluded. ECOD v295.2; the method follows the ECOD 2027 update, whose published figures used a slightly different artifact filter.

DrugBank compounds

DrugBank	PDB ligand	Name	Domains
DB04276	E64	4-[[(2S)-2-[[(2S)-3-Carboxy-2-hydroxypropanoyl]amino]-4-methylpentanoyl]amino]butyl-(diaminomethylidene)azanium	46
DB00141	NAG	N-Acetylglucosamine	37
DB14981	IHP	Phytic acid	21
DB01992	COA	Coenzyme A	16
DB03345	BME	Mercaptoethanol	13
DB04315	GDP	Guanosine-5'-Diphosphate	11
DB08656	TTT	5-amino-2-methyl-N-[(1R)-1-naphthalen-1-ylethyl]benzamide	11
DB04349	PGO	(S)-propane-1,2-diol	8
DB03837	C1P	Morpholine-4-Carboxylic Acid (1-(3-Benzenesulfonyl-1-Phenethylallylcarbamoyl)-3-Methylbutyl)-Amide	7
DB02855	074	N-(3-Propylcarbamoyloxirane-2-Carbonyl)-Isoleucyl-Proline	6
DB04137	GTP	Guanosine-5'-Triphosphate	6
DB04126	E6C	N-[1-Hydroxycarboxyethyl-Carbonyl]Leucylamino-2-Methyl-Butane	5
DB07878	H7J	N-[(1S)-1-{1-[(1R,3E)-1-ACETYLPENT-3-EN-1-YL]-1H-1,2,3-TRIAZOL-4-YL}-1,2-DIMETHYLPROPYL]BENZAMIDE	5
DB00123	LYS	Lysine	4
DB00171	ATP	ATP	4
DB00201	CFF	Caffeine	4
DB02766	ZFB	(3R)-3-{[(Benzyloxy)carbonyl]amino}-2-oxo-4-phenylbutane-1-diazonium	4
DB03435	UDP	Uridine-5'-Diphosphate	4
DB04427	VS4	N-{(3S)-1-[(Benzyloxy)sulfamoyl]-5-phenyl-3-pentanyl}-Nα-[(4-methyl-1-piperazinyl)carbonyl]-L-phenylalaninamide	4
DB08603	TCK	N-[(1S)-5-amino-1-(chloroacetyl)pentyl]-4-methylbenzenesulfonamide	4

Most frequently bound compounds

PDB ligand	Name	Domains in contact
ZNmetal	ZINC ION	379
CL	CHLORIDE ION	352
CAmetal	CALCIUM ION	159
NAmetal	SODIUM ION	120
E64	N-[N-[1-HYDROXYCARBOXYETHYL-CARBONYL]LEUCYLAMINO-BUTYL]-GUANIDINE	60
NAG	2-acetamido-2-deoxy-beta-D-glucopyranose	58
AYE	prop-2-en-1-amine	40
Kmetal	POTASSIUM ION	39
MGmetal	MAGNESIUM ION	24
IHP	INOSITOL HEXAKISPHOSPHATE	21
TFA	trifluoroacetic acid	20
BR	BROMIDE ION	18
COA	COENZYME A	16
NEH	ETHANAMINE	15
GVE	METHYL 4-AMINOBUTANOATE	14
UNX	UNKNOWN ATOM OR ION	14
BME	BETA-MERCAPTOETHANOL	13
GDP	GUANOSINE-5'-DIPHOSPHATE	11
TTT	5-amino-2-methyl-N-[(1R)-1-naphthalen-1-ylethyl]benzamide	11
0IW	Nalpha-[(4-methylpiperazin-1-yl)carbonyl]-N-[(3S)-1-phenyl-5-(phenylsulfonyl)pentan-3-yl]-L-phenylalaninamide	10