Annotations: 9AU1

SARS-CoV-2 XBB.1.5 RBD bound to the VIR-7229 and the S309 Fab fragments

External Resource: Annotation

Domain Annotation: ECOD Classification
SAbDab Antibody Annotation
Thera-SAbDab Antibody Annotation
Gene Ontology: Gene Product Annotation
InterPro: Protein Family Classification
Protein Modification Annotation

Domain Annotation: ECOD Classification ECOD Database Homepage

Chains	Family Name	Domain Identifier	Architecture	Possible Homology	Homology	Topology	Family	Provenance Source (Version)
E [auth R]	GFO_IDH_MocA	e9au1R01	A: beta barrels	X: cradle loop barrel	H: RIFT-related	T: acid protease	F: GFO_IDH_MocA	ECOD (v294.2)
C [auth H]	GFO_IDH_MocA	e9au1H01	A: beta barrels	X: cradle loop barrel	H: RIFT-related	T: acid protease	F: GFO_IDH_MocA	ECOD (v294.2)
B [auth N]	GFO_IDH_MocA	e9au1N01	A: beta barrels	X: cradle loop barrel	H: RIFT-related	T: acid protease	F: GFO_IDH_MocA	ECOD (v294.2)

SAbDab Antibody Annotation SAbDab Database Homepage

Chain	Chain Class	Chain Subclass	Chain Type	Antigen Name(s)	Provenance Source
D [auth L]	Light Chain	IGLV2	Lambda	sars-cov-2 xbb.1.5 rbd	SAbDab (2026-05-15)
C [auth H]	Heavy Chain	IGHV3	-	sars-cov-2 xbb.1.5 rbd	SAbDab (2026-05-15)
B [auth N]	Light Chain	IGKV3	Kappa	sars-cov-2 xbb.1.5 rbd	SAbDab (2026-05-15)
A [auth M]	Heavy Chain	IGHV1	-	sars-cov-2 xbb.1.5 rbd	SAbDab (2026-05-15)

Thera-SAbDab Antibody Annotation Thera-SAbDab Database Homepage

Chain	Name	Target	Provenance Source
B [auth N]	Beludavimab	SARS-CoV-2 Spike RBD	Therapeutic SAbDab (2026-05-15)
A [auth M]	Beludavimab	SARS-CoV-2 Spike RBD	Therapeutic SAbDab (2026-05-15)

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
E [auth R]	SARS-CoV-2 XBB.1.5 RBD	identical protein binding protein binding binding host cell surface binding host cell surface receptor binding	viral process fusion of virus membrane with host endosome membrane membrane fusion involved in viral entry into host cell virion attachment to host cell biological process involved in interspecies interaction between organisms receptor-mediated virion attachment to host cell adhesion of symbiont to host cell viral life cycle adhesion of symbiont to host biological process involved in interaction with host biological process involved in symbiotic interaction membrane organization cellular component organization membrane fusion viral process fusion of virus membrane with host endosome membrane membrane fusion involved in viral entry into host cell virion attachment to host cell biological process involved in interspecies interaction between organisms receptor-mediated virion attachment to host cell adhesion of symbiont to host cell viral life cycle adhesion of symbiont to host biological process involved in interaction with host biological process involved in symbiotic interaction membrane organization cellular component organization membrane fusion fusion of virus membrane with host plasma membrane cellular process cellular component organization or biogenesis symbiont entry into host cell symbiont entry into host endocytosis involved in viral entry into host cell regulation of biological process positive regulation of viral life cycle positive regulation of viral process biological regulation positive regulation of biological process modulation by symbiont of entry into host regulation of viral entry into host cell regulation of viral life cycle regulation of viral process positive regulation of viral entry into host cell positive regulation by symbiont of entry into host regulation of biological process involved in symbiotic interaction	cellular anatomical structure membrane virion component virion membrane host intracellular membrane-bounded organelle host cellular component host intracellular part host cell membrane other organism part host cell cytoplasm part host intracellular organelle host cell endoplasmic reticulum-Golgi intermediate compartment membrane host cell endoplasmic reticulum-Golgi intermediate compartment host cell cytoplasm cellular anatomical structure membrane virion component virion membrane host intracellular membrane-bounded organelle host cellular component host intracellular part host cell membrane other organism part host cell cytoplasm part host intracellular organelle host cell endoplasmic reticulum-Golgi intermediate compartment membrane host cell endoplasmic reticulum-Golgi intermediate compartment host cell cytoplasm host cell part host intracellular region viral membrane viral envelope host cell plasma membrane
D [auth L]	VIR-7229 Fab light chain	-	-	-
C [auth H]	VIR-7229 Fab heavy chain	-	-	-
B [auth N]	S309 Fab light chain	-	-	-
A [auth M]	S309 Fab heavy chain	-	-	-

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
E [auth R]	IPR018548	Spike (S) protein S1 subunit, receptor-binding domain, betacoronavirus	Domain
E [auth R]	IPR044341	Spike (S) protein S1 subunit, N-terminal domain, SARS-CoV-like	Domain
E [auth R]	IPR032500	Spike glycoprotein S1, N-terminal domain, betacoronavirus-like	Domain
E [auth R]	IPR042578	Spike glycoprotein, betacoronavirus	Family
E [auth R]	IPR036326	Spike S1 subunit, receptor binding domain superfamily, betacoronavirus	Homologous Superfamily
E [auth R]	IPR043002	Spike glycoprotein, N-terminal domain superfamily	Homologous Superfamily
E [auth R]	IPR044874	Spike glycoprotein S2, coronavirus, heptad repeat 2	Domain
E [auth R]	IPR044873	Spike glycoprotein S2, coronavirus, heptad repeat 1	Domain
E [auth R]	IPR043473	Spike glycoprotein S2 superfamily, coronavirus	Homologous Superfamily
E [auth R]	IPR043607	Coronavirus spike glycoprotein S1, C-terminal	Domain
E [auth R]	IPR002552	Spike glycoprotein S2, coronavirus	Domain
E [auth R]	IPR044366	Spike (S) protein S1 subunit, receptor-binding domain, SARS-CoV-2	Domain

Protein Modification Annotation

Modified Residue(s)
Chain	Residue(s)	Description
D [auth L]	PCA	Parent Component: GLN : AA0031 : 2-pyrrolidone-5-carboxylic acid (Gln) MOD:00040 , 2-pyrrolidone-5-carboxylic acid (Glu) MOD:00420

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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.