Annotations: 6Q04

Domain Annotation: SCOP2 Classification SCOP2 Database Homepage

Chains	Type	Family Name	Domain Identifier	Family Identifier	Provenance Source (Version)
A	SCOP2 Family	SARS coronavirus receptor-binding domain-like	8092523	4003874	SCOP2 (2022-06-29)
A	SCOP2 Family	Coronavirus spike S1 glycoprotein N-terminal domain-like	8092525	4004563	SCOP2 (2022-06-29)
A	SCOP2 Family	Coronavirus S2 glycoprotein stalk-like	8092527	4003119	SCOP2 (2022-06-29)
A	SCOP2 Family	Coronavirus spike S2 glycoprotein connector domain-like	8092529	4007763	SCOP2 (2022-06-29)
A	SCOP2 Family	Coronavirus S1 glycoprotein, domain C-like	8092676	4007778	SCOP2 (2022-06-29)
A	SCOP2 Family	Coronavirus S1 glycoprotein, domain D-like	8092678	4007779	SCOP2 (2022-06-29)
A	SCOP2 Superfamily	SARS coronavirus receptor-binding domain-like	8092524	3001706	SCOP2 (2022-06-29)
A	SCOP2 Superfamily	Concanavalin A-like lectins/glucanases	8092526	3000120	SCOP2 (2022-06-29)
A	SCOP2 Superfamily	Coronavirus S2 glycoprotein stalk-like	8092528	3000282	SCOP2 (2022-06-29)
A	SCOP2 Superfamily	Coronavirus spike S2 glycoprotein connector domain-like	8092530	3002562	SCOP2 (2022-06-29)
A	SCOP2 Superfamily	Coronavirus S1 glycoprotein, domain C-like	8092677	3002615	SCOP2 (2022-06-29)
A	SCOP2 Superfamily	Coronavirus S1 glycoprotein, domain D-like	8092679	3002616	SCOP2 (2022-06-29)
B	SCOP2B Superfamily	Coronavirus S2 glycoprotein stalk-like	8092528	3000282	SCOP2B (2022-06-29)
B	SCOP2B Superfamily	Coronavirus spike S2 glycoprotein connector domain-like	8092530	3002562	SCOP2B (2022-06-29)
B	SCOP2B Superfamily	SARS coronavirus receptor-binding domain-like	8092524	3001706	SCOP2B (2022-06-29)
B	SCOP2B Superfamily	Coronavirus S1 glycoprotein, domain C-like	8092677	3002615	SCOP2B (2022-06-29)
B	SCOP2B Superfamily	Concanavalin A-like lectins/glucanases	8092526	3000120	SCOP2B (2022-06-29)
C	SCOP2B Superfamily	Coronavirus spike S2 glycoprotein connector domain-like	8092530	3002562	SCOP2B (2022-06-29)
C	SCOP2B Superfamily	Coronavirus S1 glycoprotein, domain C-like	8092677	3002615	SCOP2B (2022-06-29)
C	SCOP2B Superfamily	Coronavirus S2 glycoprotein stalk-like	8092528	3000282	SCOP2B (2022-06-29)
C	SCOP2B Superfamily	SARS coronavirus receptor-binding domain-like	8092524	3001706	SCOP2B (2022-06-29)
C	SCOP2B Superfamily	Concanavalin A-like lectins/glucanases	8092526	3000120	SCOP2B (2022-06-29)

Domain Annotation: ECOD Classification ECOD Database Homepage

Chains	Family Name	Domain Identifier	Architecture	Possible Homology	Homology	Topology	Family	Provenance Source (Version)
A	Spike_NTD	e6q04A3	A: beta sandwiches	X: jelly-roll	H: Concanavalin A-like	T: Concanavalin A-like lectins/glucanases	F: Spike_NTD	ECOD (1.6)
A	Corona_S1_3rd	e6q04A2	A: beta complex topology	X: Beta domain of coronavirus spike glycoprotein (From Topology)	H: Beta domain of coronavirus spike glycoprotein (From Topology)	T: Beta domain of coronavirus spike glycoprotein	F: Corona_S1_3rd	ECOD (1.6)
A	Spike_rec_bind	e6q04A4	A: a+b three layers	X: Coronavirus spike protein receptor-binding domain (From Homology)	H: Coronavirus spike protein receptor-binding domain	T: Beta-coronavirus spike protein receptor-binding domain	F: Spike_rec_bind	ECOD (1.6)
A	Corona_S2	e6q04A1	A: a+b complex topology	X: S2 subunit of coronavirus spike glycoprotein (From Topology)	H: S2 subunit of coronavirus spike glycoprotein (From Topology)	T: S2 subunit of coronavirus spike glycoprotein	F: Corona_S2	ECOD (1.6)
B	Spike_NTD	e6q04B4	A: beta sandwiches	X: jelly-roll	H: Concanavalin A-like	T: Concanavalin A-like lectins/glucanases	F: Spike_NTD	ECOD (1.6)
B	Corona_S1_3rd	e6q04B3	A: beta complex topology	X: Beta domain of coronavirus spike glycoprotein (From Topology)	H: Beta domain of coronavirus spike glycoprotein (From Topology)	T: Beta domain of coronavirus spike glycoprotein	F: Corona_S1_3rd	ECOD (1.6)
B	Spike_rec_bind	e6q04B1	A: a+b three layers	X: Coronavirus spike protein receptor-binding domain (From Homology)	H: Coronavirus spike protein receptor-binding domain	T: Beta-coronavirus spike protein receptor-binding domain	F: Spike_rec_bind	ECOD (1.6)
B	Corona_S2	e6q04B2	A: a+b complex topology	X: S2 subunit of coronavirus spike glycoprotein (From Topology)	H: S2 subunit of coronavirus spike glycoprotein (From Topology)	T: S2 subunit of coronavirus spike glycoprotein	F: Corona_S2	ECOD (1.6)
C	Spike_NTD	e6q04C3	A: beta sandwiches	X: jelly-roll	H: Concanavalin A-like	T: Concanavalin A-like lectins/glucanases	F: Spike_NTD	ECOD (1.6)
C	Corona_S1_3rd	e6q04C2	A: beta complex topology	X: Beta domain of coronavirus spike glycoprotein (From Topology)	H: Beta domain of coronavirus spike glycoprotein (From Topology)	T: Beta domain of coronavirus spike glycoprotein	F: Corona_S1_3rd	ECOD (1.6)
C	Spike_rec_bind	e6q04C4	A: a+b three layers	X: Coronavirus spike protein receptor-binding domain (From Homology)	H: Coronavirus spike protein receptor-binding domain	T: Beta-coronavirus spike protein receptor-binding domain	F: Spike_rec_bind	ECOD (1.6)
C	Corona_S2	e6q04C1	A: a+b complex topology	X: S2 subunit of coronavirus spike glycoprotein (From Topology)	H: S2 subunit of coronavirus spike glycoprotein (From Topology)	T: S2 subunit of coronavirus spike glycoprotein	F: Corona_S2	ECOD (1.6)

Protein Family Annotation Pfam Database Homepage

Chains	Accession	Name	Description	Comments	Source
A, B, C	PF01601	Coronavirus spike glycoprotein S2 (CoV_S2)	Coronavirus spike glycoprotein S2	-	Family
A, B, C	PF16451	Betacoronavirus-like spike glycoprotein S1, N-terminal (bCoV_S1_N)	Betacoronavirus-like spike glycoprotein S1, N-terminal	This entry represents the N-terminal domain of the betacoronavirus-like trimeric spike glycoprotein. The distal S1 subunit of the coronavirus spike protein is responsible for receptor binding. S1 contains two domains; an N-terminal galectin-like doma ...	This entry represents the N-terminal domain of the betacoronavirus-like trimeric spike glycoprotein. The distal S1 subunit of the coronavirus spike protein is responsible for receptor binding. S1 contains two domains; an N-terminal galectin-like domain (NTD) and a receptor-binding domain (S1 RBD) also referred to as the S1 CTD or domain B. Either the S1 NTD or S1 RBD, or occasionally both, are involved in binding to host receptors. S1 NTD is located on the side of the spike trimer and mainly recognises sugar receptors [2]. For many betacoronaviruses (b-CoVs), for example mouse hepatitis virus (MHV), the RBD is located in the NTD. The structure of the MHV S1 NTD showed the same fold as human galectins (galactose-binding lectin), however it does not bind any sugar; instead, it binds to the carcinoembryonic antigen cell-adhesion molecule CEACAM1) through protein-protein interactions [2]. All three CEACAM21a-binding sites in MHV spikes can be fully occupied by CEACAM1a. It has been shown that CEACAM1a binding to the MHV spike weakens the interactions between S1 and S2 and facilitates the proteolysis of the spike protein and dissociation of S1 [2]. The homologous bovine CoV (BCov) S1 NTD also possesses a galectin fold but binds to sialic acid-containing moieties on host cell membranes, as does the NTD of three other group A b-Covs, namely human CoV (HCoV) OC43, avian b-CoV, and infectious bronchitis virus (IBV) [3]. Despite the S1 NTD of human respiratory b-CoV HKU1 being highly homologous to the NTDs of MHV and bovine CoV, it does not bind to either sugar or human carcinoembryonic antigen-related cell adhesion molecules (CEACAMs) and the RBD is found instead in the S1 RBD domain [3].	Domain
A, B, C	PF09408	Betacoronavirus spike glycoprotein S1, receptor binding (bCoV_S1_RBD)	Betacoronavirus spike glycoprotein S1, receptor binding	This entry represents the receptor binding domain (S1 RBD) of the betacoronavirus spike glycoprotein. The spike glycoprotein is arranged in trimers on the surface of the viral membrane and is essential for viral entry. The spike protein is translat ...	This entry represents the receptor binding domain (S1 RBD) of the betacoronavirus spike glycoprotein. The spike glycoprotein is arranged in trimers on the surface of the viral membrane and is essential for viral entry. The spike protein is translated as a large polypeptide that is subsequently cleaved to the distal S1, responsible for receptor binding, and the membrane-anchored S2 responsible for membrane fusion [1]. The coronavirus (SARS-CoV) S1 subunit is composed of two distinct domains: an N-terminal domain (S1 NTD) and a receptor-binding domain (S1 RBD) also referred to as the S1 CTD or domain B. Each of these domains have been implicated in binding to host receptors. However, most coronaviruses are not known to utilise both the S1 NTD and S1 RBD for viral entry [2]. SARS-CoV makes use of its S1 RBD to bind to the human angiotensin-converting enzyme 2 (ACE2) as its host receptor [3,4].	Domain
A, B, C	PF19209	Coronavirus spike glycoprotein S1, C-terminal (CoV_S1_C)	Coronavirus spike glycoprotein S1, C-terminal	This entry represents a domain found at the C-terminus of the Coronavirus S1 protein. It is found across a range of alpha, beta and gamma coronaviruses. This small all beta stranded domain is known as subdomain 2 in the structure of the porcine epide ...	This entry represents a domain found at the C-terminus of the Coronavirus S1 protein. It is found across a range of alpha, beta and gamma coronaviruses. This small all beta stranded domain is known as subdomain 2 in the structure of the porcine epidemic diarrhea virus spike protein [1].	Domain

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
A, B, C	Spike glycoprotein	-	viral process fusion of virus membrane with host endosome membrane membrane fusion involved in viral entry into host cell membrane organization cellular component organization membrane fusion cellular process cellular component organization or biogenesis import into cell receptor-mediated endocytosis of virus by host cell biological process involved in interspecies interaction between organisms transport viral life cycle establishment of localization viral process fusion of virus membrane with host endosome membrane membrane fusion involved in viral entry into host cell membrane organization cellular component organization membrane fusion cellular process cellular component organization or biogenesis import into cell receptor-mediated endocytosis of virus by host cell biological process involved in interspecies interaction between organisms transport viral life cycle establishment of localization biological process involved in interaction with host vesicle-mediated transport biological process involved in symbiotic interaction localization symbiont entry into host cell symbiont entry into host endocytosis involved in viral entry into host cell receptor-mediated endocytosis endocytosis virion attachment to host cell receptor-mediated virion attachment to host cell adhesion of symbiont to host cell adhesion of symbiont to host fusion of virus membrane with host plasma membrane 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 host intracellular membrane-bounded organelle host cellular component host intracellular part host cell membrane 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 host cell plasma membrane cellular anatomical structure membrane host intracellular membrane-bounded organelle host cellular component host intracellular part host cell membrane 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 host cell plasma membrane virion component virion membrane viral membrane viral envelope

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
A, B, C	IPR044376	Spike (S) protein S1 subunit, receptor-binding domain, MERS-CoV	Domain
A, B, C	IPR043614	Spike glycoprotein S2, coronavirus, C-terminal	Domain
A, B, C	IPR044873	Spike glycoprotein S2, coronavirus, heptad repeat 1	Domain
A, B, C	IPR018548	Spike (S) protein S1 subunit, receptor-binding domain, betacoronavirus	Domain
A, B, C	IPR032500	Spike glycoprotein S1, N-terminal domain, betacoronavirus-like	Domain
A, B, C	IPR042578	Spike glycoprotein, betacoronavirus	Family
A, B, C	IPR036326	Spike S1 subunit, receptor binding domain superfamily, betacoronavirus	Homologous Superfamily
A, B, C	IPR043002	Spike glycoprotein, N-terminal domain superfamily	Homologous Superfamily
A, B, C	IPR044874	Spike glycoprotein S2, coronavirus, heptad repeat 2	Domain
A, B, C	IPR044337	Spike (S) protein S1 subunit, N-terminal domain, MERS-CoV-like	Domain
A, B, C	IPR043473	Spike glycoprotein S2 superfamily, coronavirus	Homologous Superfamily
A, B, C	IPR043607	Coronavirus spike glycoprotein S1, C-terminal	Domain
A, B, C	IPR002552	Spike glycoprotein S2, coronavirus	Domain