X-group (possible homology)

216 UBC-like

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Ligands and drugs

2,773

Member domains

269

with ligand contacts (≤ 4 Å)

9.7% of members

204

with DrugDomain annotations

7.4% of members

117

with a DrugBank compound

4.2% 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.

Proteins with classified ligands

Superclasses bound (of 23)

7.5

Superclasses per 20 proteins

narrower than 51% 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 non-metal compounds	12	6.2	1.95×	q = 0.02
Homogeneous metal compounds	12	14.0	0.85×	q = 0.54
Organic oxygen compounds	2	5.7	0.35×	q = 0.15
Nucleosides, nucleotides, and analogues	0	7.9	0	q = 5.5e-4
Organosulfur compounds	7	0.6	12×	not tested
Benzenoids	5	2.1	2.39×	not tested
Organic nitrogen compounds	2	0.9	2.19×	not tested
Organoheterocyclic compounds	5	4.4	1.14×	not tested
Organic acids and derivatives	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
DB03345	BME	Mercaptoethanol	6
DB00172	PRO	Proline	2
DB02418	—	(R,R)-2,3-Butanediol	1
DB03309	NHE	N-cyclohexyltaurine	1

Most frequently bound compounds

PDB ligand	Name	Domains in contact
A1AIV	4-aminobutanenitrile	29
CL	CHLORIDE ION	24
NAmetal	SODIUM ION	24
ZNmetal	ZINC ION	13
U94	4,5-dideoxy-5-(3',5'-dichlorobiphenyl-4-yl)-4-[(methoxyacetyl)amino]-L-arabinonic acid	9
BME	BETA-MERCAPTOETHANOL	7
AUmetal	GOLD ION	6
SCN	THIOCYANATE ION	5
SY8	5-azanylpentan-2-one	5
GZM	4-[(3',5'-dichloro[1,1'-biphenyl]-4-yl)methyl]-N-ethyl-1-(methoxyacetyl)piperidine-4-carboxamide	4
P6G	HEXAETHYLENE GLYCOL	4
UNX	UNKNOWN ATOM OR ION	3
5VL	2-(2-hydroxyphenyl)phenol	2
5VM	5-chloranyl-3~{H}-1,3-benzoxazole-2-thione	2
6LN	ethane-1,2-dithiol	2
CUmetal	COPPER (II) ION	2
G1V	N-[(1R,5S)-3-azabicyclo[3.1.0]hexan-6-yl]-1-[2,6-bis(chloranyl)phenyl]carbonyl-4-[[2,6-bis(chloranyl)phenyl]carbonylamino]pyrazole-3-carboxamide	2
IOD	IODIDE ION	2
PA0	Phenylarsine oxide	2
PRO	PROLINE	2