X-group (possible homology)

102 HhH/H2TH

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Ligands and drugs

24,989

Member domains

3,327

with ligand contacts (≤ 4 Å)

13.3% of members

2,674

with DrugDomain annotations

10.7% of members

964

with a DrugBank compound

3.9% 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.

185

Proteins with classified ligands

Superclasses bound (of 23)

6.9

Superclasses per 20 proteins

narrower than 61% 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
Homogeneous metal compounds	112	89.5	1.25×	q = 2.7e-3
Homogeneous non-metal compounds	48	39.3	1.22×	q = 0.18
Nucleosides, nucleotides, and analogues	55	50.4	1.09×	q = 0.54
Organoheterocyclic compounds	19	28.1	0.68×	q = 0.10
Organic oxygen compounds	23	36.3	0.63×	q = 0.02
Benzenoids	8	13.3	0.60×	q = 0.21
Organic acids and derivatives	11	28.2	0.39×	q = 4.0e-4
Organic nitrogen compounds	1	5.8	0.17×	q = 0.06
Lipids and lipid-like molecules	0	20.3	0	q < 0.0001
Mixed metal/non-metal compounds	4	3.8	1.04×	not tested
Organosulfur compounds	3	3.8	0.80×	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
DB03345	BME	BETA-MERCAPTOETHANOL	65
DB04447	DTT	2,3-DIHYDROXY-1,4-DITHIOBUTANE	48
DB00171	ATP	ADENOSINE-5'-TRIPHOSPHATE	41
DB04005	UTP	URIDINE 5'-TRIPHOSPHATE	35
DB02431	CTP	CYTIDINE-5'-TRIPHOSPHATE	32
DB03317	HEC	HEME C	25
DB04137	GTP	GUANOSINE-5'-TRIPHOSPHATE	22
DB03798	DC	2'-DEOXYCYTIDINE-5'-MONOPHOSPHATE	18
DB16833	ADP	ADENOSINE-5'-DIPHOSPHATE	18
DB02596	APC	DIPHOSPHOMETHYLPHOSPHONIC ACID ADENOSYL ESTER	15
DB04104	ADK	3-METHYL-3H-PURIN-6-YLAMINE	12
DB12010	—	—	11
DB04450	HTG	heptyl 1-thio-beta-D-glucopyranoside	10
DB01860	3AT	3'-DEOXYADENOSINE-5'-TRIPHOSPHATE	9
DB00118	SAM	S-ADENOSYLMETHIONINE	7
DB00131	AMP	ADENOSINE MONOPHOSPHATE	7
DB01592	—	—	5
DB01972	5GP	GUANOSINE-5'-MONOPHOSPHATE	5
DB02181	DGT	2'-DEOXYGUANOSINE-5'-TRIPHOSPHATE	5
DB02883	DOC	2',3'-DIDEOXYCYTIDINE-5'-MONOPHOSPHATE	5

Most frequently bound compounds

PDB ligand	Name	Domains in contact
NAmetal	SODIUM ION	1,013
MGmetal	MAGNESIUM ION	670
CL	CHLORIDE ION	246
CAmetal	CALCIUM ION	231
ZNmetal	ZINC ION	187
Kmetal	POTASSIUM ION	112
MNmetal	MANGANESE (II) ION	95
OHX	osmium (III) hexammine	63
SF4	IRON/SULFUR CLUSTER	52
DTT	2,3-DIHYDROXY-1,4-DITHIOBUTANE	50
NImetal	NICKEL (II) ION	42
ATP	ADENOSINE-5'-TRIPHOSPHATE	41
BME	BETA-MERCAPTOETHANOL	40
UTP	URIDINE 5'-TRIPHOSPHATE	37
CTP	CYTIDINE-5'-TRIPHOSPHATE	33
GTP	GUANOSINE-5'-TRIPHOSPHATE	21
ADP	ADENOSINE-5'-DIPHOSPHATE	18
IOD	IODIDE ION	16
APC	DIPHOSPHOMETHYLPHOSPHONIC ACID ADENOSYL ESTER	15
ADK	3-METHYL-3H-PURIN-6-YLAMINE	12