Annotations: 4RDQ

Calcium-activated chloride channel bestrophin-1, from chicken, in complex with Fab antibody fragments, chloride and calcium

External Resource: Annotation

Domain Annotation: SCOP/SCOPe Classification
Domain Annotation: ECOD Classification
Domain Annotation: CATH
IMGT Antibody Annotation
SAbDab Antibody Annotation
Protein Family Annotation
Gene Ontology: Gene Product Annotation
InterPro: Protein Family Classification
Membrane Protein Annotation: OPM
Membrane Protein Annotation: PDBTM
Membrane Protein Annotation: MemProtMD
Membrane Protein Annotation: mpstruc

Domain Annotation: SCOP/SCOPe Classification SCOP-e Database Homepage

Chains	Domain Info	Class	Fold	Superfamily	Family	Domain	Species	Provenance Source (Version)
F	d4rdqf2	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	C1 set domains (antibody constant domain-like)	automated matches	(Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)
F	d4rdqf1	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	automated matches	automated matches	(Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)
H	d4rdqh2	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	C1 set domains (antibody constant domain-like)	automated matches	(Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)
H	d4rdqh1	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	automated matches	automated matches	(Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)
J	d4rdqj2	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	C1 set domains (antibody constant domain-like)	automated matches	(Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)
J	d4rdqj1	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	automated matches	automated matches	(Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)
N	d4rdqn2	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	C1 set domains (antibody constant domain-like)	automated matches	(Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)
N	d4rdqn1	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	automated matches	automated matches	(Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)
L	d4rdql2	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	C1 set domains (antibody constant domain-like)	automated matches	(Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)
L	d4rdql1	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	automated matches	automated matches	(Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)
G	d4rdqg1	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	V set domains (antibody variable domain-like)	automated matches	(Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)
G	d4rdqg2	Artifacts	Tags	Tags	Tags	N-terminal Tags	(Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)
I	d4rdqi1	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	V set domains (antibody variable domain-like)	automated matches	(Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)
I	d4rdqi2	Artifacts	Tags	Tags	Tags	N-terminal Tags	(Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)
M	d4rdqm1	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	V set domains (antibody variable domain-like)	automated matches	(Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)
M	d4rdqm2	Artifacts	Tags	Tags	Tags	N-terminal Tags	(Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)
O	d4rdqo1	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	V set domains (antibody variable domain-like)	automated matches	(Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)
O	d4rdqo2	Artifacts	Tags	Tags	Tags	N-terminal Tags	(Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)
K	d4rdqk1	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	V set domains (antibody variable domain-like)	automated matches	(Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)
K	d4rdqk2	Artifacts	Tags	Tags	Tags	N-terminal Tags	(Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)

Domain Annotation: ECOD Classification ECOD Database Homepage

Chains	Family Name	Domain Identifier	Architecture	Possible Homology	Homology	Topology	Family	Provenance Source (Version)
B	H_PPase	e4rdqB1	A: alpha arrays	X: jelly-roll	H: Double-stranded beta-helix	T: Double-stranded beta-helix	F: H_PPase	ECOD (v295.2)
D	H_PPase	e4rdqD1	A: alpha arrays	X: jelly-roll	H: Double-stranded beta-helix	T: Double-stranded beta-helix	F: H_PPase	ECOD (v295.2)
E	H_PPase	e4rdqE1	A: alpha arrays	X: jelly-roll	H: Double-stranded beta-helix	T: Double-stranded beta-helix	F: H_PPase	ECOD (v295.2)
C	H_PPase	e4rdqC1	A: alpha arrays	X: jelly-roll	H: Double-stranded beta-helix	T: Double-stranded beta-helix	F: H_PPase	ECOD (v295.2)
A	PCI	e4rdqA1	A: alpha arrays	X: jelly-roll	H: Double-stranded beta-helix	T: N-terminal domain of Delta(14)-sterol reductase, MaSR1	F: PCI	ECOD (v295.2)
F	Rhv	e4rdqF1	A: alpha arrays	X: Insertion subdomain in DsbA-like	H: Insertion subdomain in DsbA-like	T: Insertion subdomain in DsbA-like	F: Rhv	ECOD (v295.2)
H	Rhv	e4rdqH1	A: alpha arrays	X: Insertion subdomain in DsbA-like	H: Insertion subdomain in DsbA-like	T: Insertion subdomain in DsbA-like	F: Rhv	ECOD (v295.2)
J	Rhv	e4rdqJ1	A: alpha arrays	X: Insertion subdomain in DsbA-like	H: Insertion subdomain in DsbA-like	T: Insertion subdomain in DsbA-like	F: Rhv	ECOD (v295.2)
N	Rhv	e4rdqN1	A: alpha arrays	X: Insertion subdomain in DsbA-like	H: Insertion subdomain in DsbA-like	T: Insertion subdomain in DsbA-like	F: Rhv	ECOD (v295.2)
L	Rhv	e4rdqL1	A: alpha arrays	X: Insertion subdomain in DsbA-like	H: Insertion subdomain in DsbA-like	T: Insertion subdomain in DsbA-like	F: Rhv	ECOD (v295.2)
G	Rhv	e4rdqG1	A: alpha arrays	X: Insertion subdomain in DsbA-like	H: Insertion subdomain in DsbA-like	T: Insertion subdomain in DsbA-like	F: Rhv	ECOD (v295.2)
I	Rhv	e4rdqI1	A: alpha arrays	X: Insertion subdomain in DsbA-like	H: Insertion subdomain in DsbA-like	T: Insertion subdomain in DsbA-like	F: Rhv	ECOD (v295.2)
M	Rhv	e4rdqM1	A: alpha arrays	X: Insertion subdomain in DsbA-like	H: Insertion subdomain in DsbA-like	T: Insertion subdomain in DsbA-like	F: Rhv	ECOD (v295.2)
O	Rhv	e4rdqO1	A: alpha arrays	X: Insertion subdomain in DsbA-like	H: Insertion subdomain in DsbA-like	T: Insertion subdomain in DsbA-like	F: Rhv	ECOD (v295.2)
K	Rhv	e4rdqK1	A: alpha arrays	X: Insertion subdomain in DsbA-like	H: Insertion subdomain in DsbA-like	T: Insertion subdomain in DsbA-like	F: Rhv	ECOD (v295.2)

Domain Annotation: CATH CATH Database Homepage

Chain	Domain	Class	Architecture	Topology	Homology	Provenance Source (Version)
F	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
H	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
J	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
N	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
L	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
G	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
I	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
M	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
O	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
K	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)

IMGT Antibody Annotation IMGT Database Homepage

Chain	Protein Name	Description	Organism Name	Gene Allele Name(s)	Domain Name(s)	Receptor Type	Receptor Description	Provenance Source
F, H, J, L, N	Fab antibody	L-KAPPA	Mus musculus (house mouse)	IGKV12-4401, IGKJ102, IGKC01, IGKC02	V-DOMAIN V-KAPPA, C-DOMAIN C-KAPPA	IG	FAB-GAMMA-1_KAPPA	IMGT (202636-0)
G, I, K, M, O	Fab antibody	VH-CH1	Mus musculus (house mouse)	IGHV1-6902, IGHJ201, IGHG1*02	V-DOMAIN VH, C-DOMAIN CH1	IG	FAB-GAMMA-1_KAPPA	IMGT (202636-0)

SAbDab Antibody Annotation SAbDab Database Homepage

Chain	Chain Class	Chain Subclass	Chain Type	Antigen Name(s)	Provenance Source
F, H, J, L, N	Light Chain	IGKV12	Kappa	bestrophin-1	SAbDab (2026-09-18)
G, I, K, M, O	Heavy Chain	IGHV1	-	bestrophin-1	SAbDab (2026-09-18)

Protein Family Annotation Pfam Database Homepage

Chains	Accession	Name	Description	Comments	Source
A, B, C, D, E	PF01062	Bestrophin, RFP-TM, chloride channel (Bestrophin)	Bestrophin, RFP-TM, chloride channel	-	Family
G, I, K, M, O	PF07654	Immunoglobulin C1-set domain (C1-set)	Immunoglobulin C1-set domain		Domain

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
A, B, C, D, E	Bestrophin-1	bicarbonate transmembrane transporter activity passive transmembrane transporter activity bicarbonate channel activity channel activity transporter activity transmembrane transporter activity monoatomic anion transmembrane transporter activity chloride transmembrane transporter activity monoatomic ion channel activity monoatomic anion channel activity monoatomic ion transmembrane transporter activity chloride channel activity identical protein binding protein binding bicarbonate transmembrane transporter activity passive transmembrane transporter activity bicarbonate channel activity channel activity transporter activity transmembrane transporter activity monoatomic anion transmembrane transporter activity chloride transmembrane transporter activity monoatomic ion channel activity monoatomic anion channel activity monoatomic ion transmembrane transporter activity chloride channel activity identical protein binding protein binding binding gated channel activity intracellularly calcium-gated channel activity intracellularly calcium-gated chloride channel activity ligand-gated monoatomic anion channel activity ligand-gated channel activity ligand-gated monoatomic ion channel activity	cellular component organization cellular component biogenesis cellular component assembly protein-containing complex organization protein complex oligomerization protein-containing complex assembly cellular process cellular component organization or biogenesis localization transepithelial chloride transport transepithelial transport transport monoatomic anion transport monoatomic ion transport cellular component organization cellular component biogenesis cellular component assembly protein-containing complex organization protein complex oligomerization protein-containing complex assembly cellular process cellular component organization or biogenesis localization transepithelial chloride transport transepithelial transport transport monoatomic anion transport monoatomic ion transport establishment of localization chloride transport inorganic anion transport nitrogen compound transport carboxylic acid transport secretion export from cell organic acid transport amino acid transport acidic amino acid transport secretion by cell dicarboxylic acid transport glutamate secretion monoatomic ion transmembrane transport transmembrane transport chloride transmembrane transport monoatomic anion transmembrane transport regulation of synaptic plasticity trans-synaptic signaling regulation of biological process regulation of signaling regulation of cellular process modulation of chemical synaptic transmission signaling biological regulation cell-cell signaling chemical synaptic transmission cell communication synaptic signaling regulation of trans-synaptic signaling anterograde trans-synaptic signaling regulation of cell communication regulation of biological quality cellular localization gamma-aminobutyric acid transport signal release establishment of localization in cell synaptic transmission, GABAergic gamma-aminobutyric acid secretion neurotransmitter secretion acid secretion neurotransmitter transport signal release from synapse gamma-aminobutyric acid secretion, neurotransmission	protein-containing complex cellular anatomical structure transmembrane transporter complex membrane chloride channel complex membrane protein complex transporter complex monoatomic ion channel complex membrane microdomain cell periphery plasma membrane basal part of cell basal plasma membrane plasma membrane region protein-containing complex cellular anatomical structure transmembrane transporter complex membrane chloride channel complex membrane protein complex transporter complex monoatomic ion channel complex membrane microdomain cell periphery plasma membrane basal part of cell basal plasma membrane plasma membrane region basolateral plasma membrane presynapse synapse cell junction
F, H, J, L, N	Fab antibody fragment, light chain	-	-	cell periphery cellular anatomical structure plasma membrane membrane extracellular region
G, I, K, M, O	Fab antibody fragment, heavy chain	-	-	cellular anatomical structure extracellular region

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
A, B, C, D, E	IPR000615	Bestrophin	Family
A, B, C, D, E	IPR021134	Bestrophin-like	Family
F, H, J, L, N	IPR003597	Immunoglobulin C1-set	Domain
F, H, J, L, N	IPR050150	Immunoglobulin Variable Light Chain	Family
F, H, J, L, N	IPR013783	Immunoglobulin-like fold	Homologous Superfamily
F, H, J, L, N	IPR036179	Immunoglobulin-like domain superfamily	Homologous Superfamily
F, H, J, L, N	IPR013106	Immunoglobulin V-set domain	Domain
F, H, J, L, N	IPR003599	Immunoglobulin domain subtype	Domain
F, H, J, L, N	IPR007110	Immunoglobulin-like domain	Domain
F, H, J, L, N	IPR003006	Immunoglobulin/major histocompatibility complex, conserved site	Conserved Site
G, I, K, M, O	IPR003597	Immunoglobulin C1-set	Domain
G, I, K, M, O	IPR013783	Immunoglobulin-like fold	Homologous Superfamily
G, I, K, M, O	IPR036179	Immunoglobulin-like domain superfamily	Homologous Superfamily
G, I, K, M, O	IPR007110	Immunoglobulin-like domain	Domain
G, I, K, M, O	IPR050380	Immune Recognition and Response Modulators	Family

Membrane Protein Annotation: OPM OPM Database Homepage

Chains	External Link	Type	Class	Superfamily	Family
A, B, C, D, E A, B, C, D, E, F, H, J, L, N	OPM	Transmembrane	Alpha-helical polytopic	Bestrophin anion channel	Bestrophin anion channel

Membrane Protein Annotation: PDBTM PDBTM Database Homepage

Chains	External Link	Comment
A, B, C, D, E A, B, C, D, E, F, H, J, L, N	PDBTM	Annotated as membrane protein by PDBTM

Membrane Protein Annotation: MemProtMD MemProtMD Database Homepage

Chains	External Link	Comment
A, B, C, D, E A, B, C, D, E, F, H, J, L, N	MemProtMD	Annotated as membrane protein by MemProtMD

Membrane Protein Annotation: mpstruc mpstruc Database Homepage

Chains	Resource Link	Group	Subgroup	Protein
A, B, C, D, E A, B, C, D, E, F, H, J, L, N	mpstruc	TRANSMEMBRANE PROTEINS: ALPHA-HELICAL	Channels: Other Ion Channels	Bestrophin-1 (BEST1) Ca²⁺-activated Cl^- channel