Annotations: 9QUW

Cryo-EM structure of the human NHA2-Fab complex bound to phloretin

External Resource: Annotation

Domain Annotation: ECOD Classification
SAbDab Antibody Annotation
Protein Family Annotation
Gene Ontology: Gene Product Annotation
InterPro: Protein Family Classification
Pharos: Disease Associations
Membrane Protein Annotation: MemProtMD

Domain Annotation: ECOD Classification ECOD Database Homepage

Chains	Family Name	Domain Identifier	Architecture	Possible Homology	Homology	Topology	Family	Provenance Source (Version)
E [auth B]	RVP	e9quwB1	A: beta barrels	X: cradle loop barrel	H: RIFT-related	T: acid protease	F: RVP	ECOD (v294.2)
D [auth A]	RVP	e9quwA1	A: beta barrels	X: cradle loop barrel	H: RIFT-related	T: acid protease	F: RVP	ECOD (v294.2)

SAbDab Antibody Annotation SAbDab Database Homepage

Chain	Chain Class	Chain Subclass	Chain Type	Antigen Name(s)	Provenance Source
A [auth E], F [auth C]	Light Chain	IGKV10	Kappa	sodium/hydrogen exchanger 9b2	SAbDab (2026-06-12)
B [auth D], C [auth F]	Heavy Chain	IGHV1	-	sodium/hydrogen exchanger 9b2	SAbDab (2026-06-12)

Protein Family Annotation Pfam Database Homepage

Chains	Accession	Name	Description	Comments	Source
D [auth A], E [auth B]	PF00999	Sodium/hydrogen exchanger, transmembrane (Na_H_Exchanger)	Sodium/hydrogen exchanger, transmembrane	Na/H antiporters are key transporters in maintaining the pH of actively metabolising cells. The molecular mechanisms of antiport are unclear. These antiporters contain 10-12 transmembrane regions (M) at the amino-terminus and a large cytoplasmic regi ...	Na/H antiporters are key transporters in maintaining the pH of actively metabolising cells. The molecular mechanisms of antiport are unclear. These antiporters contain 10-12 transmembrane regions (M) at the amino-terminus and a large cytoplasmic region at the carboxyl terminus. The transmembrane regions M3-M12 share identity with other members of the family. The M6 and M7 regions are highly conserved. Thus, this is thought to be the region that is involved in the transport of sodium and hydrogen ions. The cytoplasmic region has little similarity throughout the family. This entry represents the transmembrane region.	Domain

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
A [auth E], F [auth C]	Fab light chain	-	-	-
B [auth D], C [auth F]	Fab heavy chain	-	-	-
D [auth A], E [auth B]	Sodium/hydrogen exchanger 9B2	monoatomic cation transmembrane transporter activity metal cation:monoatomic cation antiporter activity proton transmembrane transporter activity sodium:proton antiporter activity sodium ion transmembrane transporter activity secondary active transmembrane transporter activity antiporter activity metal cation:proton antiporter activity active transmembrane transporter activity monoatomic ion transmembrane transporter activity transporter activity metal ion transmembrane transporter activity transmembrane transporter activity lithium:proton antiporter activity monoatomic cation transmembrane transporter activity metal cation:monoatomic cation antiporter activity proton transmembrane transporter activity sodium:proton antiporter activity sodium ion transmembrane transporter activity secondary active transmembrane transporter activity antiporter activity metal cation:proton antiporter activity active transmembrane transporter activity monoatomic ion transmembrane transporter activity transporter activity metal ion transmembrane transporter activity transmembrane transporter activity lithium:proton antiporter activity identical protein binding protein binding binding	localization transport monoatomic ion transport lithium ion transport monoatomic cation transport establishment of localization metal ion transport sodium ion transport transmembrane transport monoatomic ion transmembrane transport cellular process sodium ion homeostasis inorganic ion homeostasis chemical homeostasis localization transport monoatomic ion transport lithium ion transport monoatomic cation transport establishment of localization metal ion transport sodium ion transport transmembrane transport monoatomic ion transmembrane transport cellular process sodium ion homeostasis inorganic ion homeostasis chemical homeostasis homeostatic process monoatomic ion homeostasis monoatomic cation homeostasis cellular response to stimulus regulation of localization establishment of protein localization regulation of cellular process nitrogen compound transport response to stimulus cell communication carbohydrate homeostasis establishment of localization in cell intracellular protein localization regulation of biological quality regulation of peptide hormone secretion regulation of biological process regulation of hormone levels establishment of protein localization to extracellular region intracellular glucose homeostasis protein secretion cellular response to oxygen-containing compound regulation of protein secretion regulation of secretion cellular response to carbohydrate stimulus response to glucose response to chemical glucose homeostasis insulin secretion involved in cellular response to glucose stimulus cellular localization regulation of hormone secretion regulation of protein localization regulation of peptide secretion signaling hormone secretion protein localization to extracellular region peptide secretion regulation of secretion by cell secretion by cell response to monosaccharide response to carbohydrate signal release cellular response to hexose stimulus intracellular chemical homeostasis cellular response to monosaccharide stimulus regulation of signaling regulation of transport secretion regulation of peptide transport biological regulation regulation of establishment of protein localization export from cell cell-cell signaling response to oxygen-containing compound cellular response to glucose stimulus regulation of protein transport peptide transport response to hexose cellular response to chemical stimulus cellular homeostasis regulation of cellular localization protein transport regulation of insulin secretion peptide hormone secretion macromolecule localization regulation of insulin secretion involved in cellular response to glucose stimulus hormone transport regulation of cell communication insulin secretion import into cell clathrin-dependent endocytosis receptor-mediated endocytosis endocytosis vesicle-mediated transport sperm motility reproductive process cilium movement involved in cell motility cilium or flagellum-dependent cell motility cilium-dependent cell motility flagellated sperm motility microtubule-based movement microtubule-based process cilium movement cell motility	membrane-bounded organelle intracellular organelle cellular anatomical structure intracellular anatomical structure mitochondrion organelle cytoplasm intracellular membrane-bounded organelle mitochondrial membrane organelle inner membrane membrane mitochondrial inner membrane organelle envelope mitochondrial envelope membrane-bounded organelle intracellular organelle cellular anatomical structure intracellular anatomical structure mitochondrion organelle cytoplasm intracellular membrane-bounded organelle mitochondrial membrane organelle inner membrane membrane mitochondrial inner membrane organelle envelope mitochondrial envelope organelle membrane endosome membrane endosome intracellular vesicle recycling endosome endomembrane system cytoplasmic vesicle membrane bounding membrane of organelle recycling endosome membrane vesicle membrane cytoplasmic vesicle vesicle cell periphery apical part of cell plasma membrane plasma membrane region apical plasma membrane basal part of cell basal plasma membrane basolateral plasma membrane synapse transport vesicle membrane presynapse synaptic vesicle synaptic vesicle membrane cell junction transport vesicle exocytic vesicle membrane secretory vesicle exocytic vesicle cell projection sperm principal piece cilium 9+2 motile cilium sperm flagellum motile cilium plasma membrane bounded cell projection

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
D [auth A], E [auth B]	IPR051843	Monovalent cation:proton antiporter 1	Family
D [auth A], E [auth B]	IPR006153	Cation/H+ exchanger, transmembrane domain	Domain
D [auth A], E [auth B]	IPR038770	Sodium/solute symporter superfamily	Homologous Superfamily

Pharos: Disease Associations Pharos Homepage Annotation

Chains	Drug Target	Associated Disease
D [auth A], E [auth B]	: Q86UD5	asthma lung carcinoma malignant pancreatic neoplasm testicular cancer atrial fibrillation malignant ependymoma medulloblastoma testicular germ cell tumor glioblastoma malignant glioma osteosarcoma ulcerative colitis

Membrane Protein Annotation: MemProtMD MemProtMD Database Homepage

Chains	External Link	Comment
D [auth A], E [auth B]	MemProtMD	Annotated as membrane protein by MemProtMD

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RCSB PDB Core Operations are funded by the U.S. National Science Foundation (DBI-2321666), the US Department of Energy (DE-SC0019749), and the National Cancer Institute, National Institute of Allergy and Infectious Diseases, and National Institute of General Medical Sciences of the National Institutes of Health under grant R01GM157729. RCSB PDB uses resources of the National Energy Research Scientific Computing Center (NERSC), a Department of Energy User Facility.