X-group (possible homology)

807 Allophycocyanin linker chain (domain)

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Ligands and drugs

267

Member domains

213

with ligand contacts (≤ 4 Å)

79.8% of members

with DrugDomain annotations

37.1% of members

with a DrugBank compound

0.0% 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)

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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	0.25×observed / expected4×	Ratio	Significance
Homogeneous metal compounds	0	6.3		0	q = 7.4e-4
Organoheterocyclic compounds	13	2.0		6.59×	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

No DrugBank compounds are annotated on this group's domains.

Most frequently bound compounds

PDB ligand	Name	Domains in contact
CYC	PHYCOCYANOBILIN	194
PEB	PHYCOERYTHROBILIN	18
PUB	PHYCOUROBILIN	2