X-group (possible homology)

604 Spectrin repeat-like

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Ligands and drugs

10,423

Member domains

957

with ligand contacts (≤ 4 Å)

9.2% of members

524

with DrugDomain annotations

5.0% of members

192

with a DrugBank compound

1.8% 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)

7.4

Superclasses per 20 proteins

narrower than 55% 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
Lipids and lipid-like molecules	8	7.3	1.10×	q = 0.76
Homogeneous non-metal compounds	14	14.0	1.00×	q = 1.00
Homogeneous metal compounds	30	31.9	0.94×	q = 0.78
Organoheterocyclic compounds	8	10.0	0.80×	q = 0.69
Organic oxygen compounds	10	13.0	0.77×	q = 0.52
Nucleosides, nucleotides, and analogues	13	18.0	0.72×	q = 0.28
Organic acids and derivatives	3	10.1	0.30×	q = 0.02
Organosulfur compounds	2	1.3	1.49×	not tested
Benzenoids	1	4.8	0.21×	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
DB03147	FAD	Flavin adenine dinucleotide	23
DB02451	BNG	B-nonylglucoside	20
DB00158	FOL	Folic acid	8
DB01373	—	—	8
DB00140	RBF	Riboflavin	7
DB03247	FMN	Flavin mononucleotide	7
DB00141	NAG	N-Acetylglucosamine	4
DB12010	—	Fostamatinib	4
DB00121	BTN	Biotin	3
DB00152	VIB	Thiamine	3
DB00171	ATP	ATP	3
DB02175	MLA	Malonic acid	3
DB14756	SRT	meso-Tartaric acid	3
DB02210	HEZ	Hexane-1,6-Diol	2
DB02693	D1D	(4S,5S)-1,2-dithiane-4,5-diol	2
DB03152	BGL	B-2-Octylglucoside	2
DB03345	BME	Mercaptoethanol	2
DB04447	DTT	1,4-Dithiothreitol	2
DB09130	—	—	2
DB00479	AKN	Amikacin	1

Most frequently bound compounds

PDB ligand	Name	Domains in contact
MGmetal	MAGNESIUM ION	663
Kmetal	POTASSIUM ION	33
CL	CHLORIDE ION	24
BNG	nonyl beta-D-glucopyranoside	21
UNL	Unknown ligand	15
NAmetal	SODIUM ION	13
PG0	2-(2-METHOXYETHOXY)ETHANOL	12
CAmetal	CALCIUM ION	8
FOL	FOLIC ACID	8
OHX	osmium (III) hexammine	8
ZNmetal	ZINC ION	8
RBF	RIBOFLAVIN	7
3PE	1,2-Distearoyl-sn-glycerophosphoethanolamine	6
FMN	FLAVIN MONONUCLEOTIDE	6
P6G	HEXAETHYLENE GLYCOL	6
PC1	1,2-DIACYL-SN-GLYCERO-3-PHOSPHOCHOLINE	6
PO3	PHOSPHITE ION	6
FAD	FLAVIN-ADENINE DINUCLEOTIDE	5
UNX	UNKNOWN ATOM OR ION	5
2VY	4-[(4-amino-2-methylpyrimidin-5-yl)methyl]-3-methylthiophene-2-carbaldehyde	4