X-group (possible homology)

142 Sigma2 domain-like

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Ligands and drugs

1,188

Member domains

with ligand contacts (≤ 4 Å)

4.7% of members

with DrugDomain annotations

3.5% of members

with a DrugBank compound

2.1% 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.

Proteins with classified ligands

Superclasses bound (of 23)

—

Superclasses per 20 proteins

fewer than 20 proteins: too few to compare at equal depth

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
Benzenoids	1	0.7	1.54×	not tested
Organoheterocyclic compounds	2	1.4	1.47×	not tested
Homogeneous metal compounds	4	4.4	0.92×	not tested
Nucleosides, nucleotides, and analogues	2	2.5	0.81×	not tested
Homogeneous non-metal compounds	1	1.9	0.52×	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
DB02693	D1D	(4S,5S)-1,2-dithiane-4,5-diol	2
DB00171	ATP	ATP	1
DB02701	NCA	Nicotinamide	1

Most frequently bound compounds

PDB ligand	Name	Domains in contact
MGmetal	MAGNESIUM ION	7
C2E	9,9'-[(2R,3R,3aS,5S,7aR,9R,10R,10aS,12S,14aR)-3,5,10,12-tetrahydroxy-5,12-dioxidooctahydro-2H,7H-difuro[3,2-d:3',2'-j][1,3,7,9,2,8]tetraoxadiphosphacyclododecine-2,9-diyl]bis(2-amino-1,9-dihydro-6H-purin-6-one)	5
Kmetal	POTASSIUM ION	3
ADP	ADENOSINE-5'-DIPHOSPHATE	2
CL	CHLORIDE ION	2
D1D	(4S,5S)-1,2-DITHIANE-4,5-DIOL	2
NAmetal	SODIUM ION	2
118	TETRAPHENYLANTIMONIUM ION	1
ATP	ADENOSINE-5'-TRIPHOSPHATE	1
CDmetal	CADMIUM ION	1
NCA	NICOTINAMIDE	1