Annotations: 5K9Q

Crystal structure of multidonor HV1-18-class broadly neutralizing Influenza A antibody 16.a.26 in complex with A/Hong Kong/1-4-MA21-1/1968 (H3N2) Hemagglutinin

External Resource: Annotation

Domain Annotation: SCOP/SCOPe Classification
Domain Annotation: ECOD Classification
Domain Annotation: CATH
IMGT Antibody Annotation
SAbDab Antibody Annotation
Gene Ontology: Gene Product Annotation
InterPro: Protein Family Classification

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

Chains	Domain Info	Class	Fold	Superfamily	Family	Domain	Species	Provenance Source (Version)
R	d5k9qr_	Coiled coil proteins	Stalk segment of viral fusion proteins	Influenza hemagglutinin (stalk)	Influenza hemagglutinin (stalk)	Influenza hemagglutinin (stalk)	(Influenza A virus (A/Hong Kong/1/1968(H3N2)) ) [TaxId: 506350 ],	SCOPe (2.08)
P	d5k9qp_	Coiled coil proteins	Stalk segment of viral fusion proteins	Influenza hemagglutinin (stalk)	Influenza hemagglutinin (stalk)	Influenza hemagglutinin (stalk)	(Influenza A virus (A/Hong Kong/1/1968(H3N2)) ) [TaxId: 506350 ],	SCOPe (2.08)
N	d5k9qn_	Coiled coil proteins	Stalk segment of viral fusion proteins	Influenza hemagglutinin (stalk)	Influenza hemagglutinin (stalk)	Influenza hemagglutinin (stalk)	(Influenza A virus (A/Hong Kong/1/1968(H3N2)) ) [TaxId: 506350 ],	SCOPe (2.08)
F	d5k9qf_	Coiled coil proteins	Stalk segment of viral fusion proteins	Influenza hemagglutinin (stalk)	Influenza hemagglutinin (stalk)	Influenza hemagglutinin (stalk)	(Influenza A virus (A/Hong Kong/1/1968(H3N2)) ) [TaxId: 506350 ],	SCOPe (2.08)
D	d5k9qd_	Coiled coil proteins	Stalk segment of viral fusion proteins	Influenza hemagglutinin (stalk)	Influenza hemagglutinin (stalk)	Influenza hemagglutinin (stalk)	(Influenza A virus (A/Hong Kong/1/1968(H3N2)) ) [TaxId: 506350 ],	SCOPe (2.08)
B	d5k9qb_	Coiled coil proteins	Stalk segment of viral fusion proteins	Influenza hemagglutinin (stalk)	Influenza hemagglutinin (stalk)	Influenza hemagglutinin (stalk)	(Influenza A virus (A/Hong Kong/1/1968(H3N2)) ) [TaxId: 506350 ],	SCOPe (2.08)
W [auth X]	d5k9qx_	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	automated matches	automated matches	(Homo sapiens ) [TaxId: 9606 ],	SCOPe (2.08)
U	d5k9qu_	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	automated matches	automated matches	(Homo sapiens ) [TaxId: 9606 ],	SCOPe (2.08)
S	d5k9qs_	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	automated matches	automated matches	(Homo sapiens ) [TaxId: 9606 ],	SCOPe (2.08)
J	d5k9qj_	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	automated matches	automated matches	(Homo sapiens ) [TaxId: 9606 ],	SCOPe (2.08)
H	d5k9qh_	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	automated matches	automated matches	(Homo sapiens ) [TaxId: 9606 ],	SCOPe (2.08)
G	d5k9qg_	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	automated matches	automated matches	(Homo sapiens ) [TaxId: 9606 ],	SCOPe (2.08)
X [auth Y]	d5k9qy2	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	C1 set domains (antibody constant domain-like)	automated matches	Human (Homo sapiens ) [TaxId: 9606 ],	SCOPe (2.08)
X [auth Y]	d5k9qy1	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	automated matches	automated matches	Human (Homo sapiens ) [TaxId: 9606 ],	SCOPe (2.08)
V	d5k9qv2	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	C1 set domains (antibody constant domain-like)	automated matches	Human (Homo sapiens ) [TaxId: 9606 ],	SCOPe (2.08)
V	d5k9qv1	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	automated matches	automated matches	Human (Homo sapiens ) [TaxId: 9606 ],	SCOPe (2.08)
T	d5k9qt2	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	C1 set domains (antibody constant domain-like)	automated matches	Human (Homo sapiens ) [TaxId: 9606 ],	SCOPe (2.08)
T	d5k9qt1	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	automated matches	automated matches	Human (Homo sapiens ) [TaxId: 9606 ],	SCOPe (2.08)
L	d5k9ql2	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	C1 set domains (antibody constant domain-like)	automated matches	Human (Homo sapiens ) [TaxId: 9606 ],	SCOPe (2.08)
L	d5k9ql1	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	automated matches	automated matches	Human (Homo sapiens ) [TaxId: 9606 ],	SCOPe (2.08)
K	d5k9qk2	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	C1 set domains (antibody constant domain-like)	automated matches	Human (Homo sapiens ) [TaxId: 9606 ],	SCOPe (2.08)
K	d5k9qk1	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	automated matches	automated matches	Human (Homo sapiens ) [TaxId: 9606 ],	SCOPe (2.08)
I	d5k9qi2	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	C1 set domains (antibody constant domain-like)	automated matches	Human (Homo sapiens ) [TaxId: 9606 ],	SCOPe (2.08)
I	d5k9qi1	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	automated matches	automated matches	Human (Homo sapiens ) [TaxId: 9606 ],	SCOPe (2.08)
Q	d5k9qq_	All beta proteins	Viral protein domain	Viral protein domain	Influenza hemagglutinin headpiece	Hemagglutinin	(Influenza A virus (A/Hong Kong/1/1968(H3N2)) ) [TaxId: 506350 ],	SCOPe (2.08)
O	d5k9qo_	All beta proteins	Viral protein domain	Viral protein domain	Influenza hemagglutinin headpiece	Hemagglutinin	(Influenza A virus (A/Hong Kong/1/1968(H3N2)) ) [TaxId: 506350 ],	SCOPe (2.08)
M	d5k9qm_	All beta proteins	Viral protein domain	Viral protein domain	Influenza hemagglutinin headpiece	Hemagglutinin	(Influenza A virus (A/Hong Kong/1/1968(H3N2)) ) [TaxId: 506350 ],	SCOPe (2.08)
E	d5k9qe_	All beta proteins	Viral protein domain	Viral protein domain	Influenza hemagglutinin headpiece	Hemagglutinin	(Influenza A virus (A/Hong Kong/1/1968(H3N2)) ) [TaxId: 506350 ],	SCOPe (2.08)
C	d5k9qc_	All beta proteins	Viral protein domain	Viral protein domain	Influenza hemagglutinin headpiece	Hemagglutinin	(Influenza A virus (A/Hong Kong/1/1968(H3N2)) ) [TaxId: 506350 ],	SCOPe (2.08)
A	d5k9qa_	All beta proteins	Viral protein domain	Viral protein domain	Influenza hemagglutinin headpiece	Hemagglutinin	(Influenza A virus (A/Hong Kong/1/1968(H3N2)) ) [TaxId: 506350 ],	SCOPe (2.08)

Domain Annotation: ECOD Classification ECOD Database Homepage

Chains	Family Name	Domain Identifier	Architecture	Possible Homology	Homology	Topology	Family	Provenance Source (Version)
R	Dynamin_N	e5k9qR1	A: alpha arrays	X: OB-fold	H: Nucleic acid-binding protein	T: Nucleic acid-binding protein	F: Dynamin_N	ECOD (v295.2)
P	Dynamin_N	e5k9qP1	A: alpha arrays	X: OB-fold	H: Nucleic acid-binding protein	T: Nucleic acid-binding protein	F: Dynamin_N	ECOD (v295.2)
N	Dynamin_N	e5k9qN1	A: alpha arrays	X: OB-fold	H: Nucleic acid-binding protein	T: Nucleic acid-binding protein	F: Dynamin_N	ECOD (v295.2)
F	Dynamin_N	e5k9qF1	A: alpha arrays	X: OB-fold	H: Nucleic acid-binding protein	T: Nucleic acid-binding protein	F: Dynamin_N	ECOD (v295.2)
D	Dynamin_N	e5k9qD1	A: alpha arrays	X: OB-fold	H: Nucleic acid-binding protein	T: Nucleic acid-binding protein	F: Dynamin_N	ECOD (v295.2)
B	Dynamin_N	e5k9qB1	A: alpha arrays	X: OB-fold	H: Nucleic acid-binding protein	T: Nucleic acid-binding protein	F: Dynamin_N	ECOD (v295.2)
W [auth X]	Dynamin_N	e5k9qX1	A: alpha arrays	X: OB-fold	H: Nucleic acid-binding protein	T: Nucleic acid-binding protein	F: Dynamin_N	ECOD (v295.2)
U	Dynamin_N	e5k9qU1	A: alpha arrays	X: OB-fold	H: Nucleic acid-binding protein	T: Nucleic acid-binding protein	F: Dynamin_N	ECOD (v295.2)
S	Dynamin_N	e5k9qS1	A: alpha arrays	X: OB-fold	H: Nucleic acid-binding protein	T: Nucleic acid-binding protein	F: Dynamin_N	ECOD (v295.2)
J	Dynamin_N	e5k9qJ1	A: alpha arrays	X: OB-fold	H: Nucleic acid-binding protein	T: Nucleic acid-binding protein	F: Dynamin_N	ECOD (v295.2)
H	Dynamin_N	e5k9qH1	A: alpha arrays	X: OB-fold	H: Nucleic acid-binding protein	T: Nucleic acid-binding protein	F: Dynamin_N	ECOD (v295.2)
G	Dynamin_N	e5k9qG1	A: alpha arrays	X: OB-fold	H: Nucleic acid-binding protein	T: Nucleic acid-binding protein	F: Dynamin_N	ECOD (v295.2)
X [auth Y]	Dynamin_N	e5k9qY1	A: alpha arrays	X: OB-fold	H: Nucleic acid-binding protein	T: Nucleic acid-binding protein	F: Dynamin_N	ECOD (v295.2)
V	Dynamin_N	e5k9qV1	A: alpha arrays	X: OB-fold	H: Nucleic acid-binding protein	T: Nucleic acid-binding protein	F: Dynamin_N	ECOD (v295.2)
T	Dynamin_N	e5k9qT1	A: alpha arrays	X: OB-fold	H: Nucleic acid-binding protein	T: Nucleic acid-binding protein	F: Dynamin_N	ECOD (v295.2)
L	Dynamin_N	e5k9qL1	A: alpha arrays	X: OB-fold	H: Nucleic acid-binding protein	T: Nucleic acid-binding protein	F: Dynamin_N	ECOD (v295.2)
K	Dynamin_N	e5k9qK1	A: alpha arrays	X: OB-fold	H: Nucleic acid-binding protein	T: Nucleic acid-binding protein	F: Dynamin_N	ECOD (v295.2)
I	Dynamin_N	e5k9qI1	A: alpha arrays	X: OB-fold	H: Nucleic acid-binding protein	T: Nucleic acid-binding protein	F: Dynamin_N	ECOD (v295.2)
Q	Dynamin_N	e5k9qQ1	A: alpha arrays	X: OB-fold	H: Nucleic acid-binding protein	T: Nucleic acid-binding protein	F: Dynamin_N	ECOD (v295.2)
O	Dynamin_N	e5k9qO1	A: alpha arrays	X: OB-fold	H: Nucleic acid-binding protein	T: Nucleic acid-binding protein	F: Dynamin_N	ECOD (v295.2)
M	Dynamin_N	e5k9qM1	A: alpha arrays	X: OB-fold	H: Nucleic acid-binding protein	T: Nucleic acid-binding protein	F: Dynamin_N	ECOD (v295.2)
E	Dynamin_N	e5k9qE1	A: alpha arrays	X: OB-fold	H: Nucleic acid-binding protein	T: Nucleic acid-binding protein	F: Dynamin_N	ECOD (v295.2)
C	Dynamin_N	e5k9qC1	A: alpha arrays	X: OB-fold	H: Nucleic acid-binding protein	T: Nucleic acid-binding protein	F: Dynamin_N	ECOD (v295.2)
A	Dynamin_N	e5k9qA1	A: alpha arrays	X: OB-fold	H: Nucleic acid-binding protein	T: Nucleic acid-binding protein	F: Dynamin_N	ECOD (v295.2)

Domain Annotation: CATH CATH Database Homepage

Chain	Domain	Class	Architecture	Topology	Homology	Provenance Source (Version)
R	3.90.20.10	Alpha Beta	Alpha-Beta Complex	Hemagglutinin Ectodomain	Chain B	CATH (4.3.0)
P	3.90.20.10	Alpha Beta	Alpha-Beta Complex	Hemagglutinin Ectodomain	Chain B	CATH (4.3.0)
N	3.90.20.10	Alpha Beta	Alpha-Beta Complex	Hemagglutinin Ectodomain	Chain B	CATH (4.3.0)
F	3.90.20.10	Alpha Beta	Alpha-Beta Complex	Hemagglutinin Ectodomain	Chain B	CATH (4.3.0)
D	3.90.20.10	Alpha Beta	Alpha-Beta Complex	Hemagglutinin Ectodomain	Chain B	CATH (4.3.0)
B	3.90.20.10	Alpha Beta	Alpha-Beta Complex	Hemagglutinin Ectodomain	Chain B	CATH (4.3.0)
W [auth X]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
U	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
S	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)
H	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)
X [auth Y]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
V	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
T	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)
K	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)
Q	3.90.209.20	Alpha Beta	Alpha-Beta Complex	Hemagglutinin (Ha1 Chain)	Chain: A	CATH (4.3.0)
O	3.90.209.20	Alpha Beta	Alpha-Beta Complex	Hemagglutinin (Ha1 Chain)	Chain: A	CATH (4.3.0)
M	3.90.209.20	Alpha Beta	Alpha-Beta Complex	Hemagglutinin (Ha1 Chain)	Chain: A	CATH (4.3.0)
E	3.90.209.20	Alpha Beta	Alpha-Beta Complex	Hemagglutinin (Ha1 Chain)	Chain: A	CATH (4.3.0)
C	3.90.209.20	Alpha Beta	Alpha-Beta Complex	Hemagglutinin (Ha1 Chain)	Chain: A	CATH (4.3.0)
A	3.90.209.20	Alpha Beta	Alpha-Beta Complex	Hemagglutinin (Ha1 Chain)	Chain: A	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
G, H, J, S, U, G, H, J, S, U, W [auth X]	Fab 16.A.26	VH-CH1	Homo sapiens (human)	IGHV1-1801, IGHV1-1804, IGHJ502, IGHG101, IGHG102, IGHG104, IGHG105, IGHG112, IGHG114, IGHG113, IGHG109, IGHG110, IGHG107, IGHG111	V-DOMAIN VH, C-DOMAIN CH1	IG	FAB-GAMMA-1_KAPPA	IMGT (202640-0)
I, K, L, T, V, I, K, L, T, V, X [auth Y]	Fab 16.A.26	L-KAPPA	Homo sapiens (human)	IGKV1-3901, IGKV1D-3901, IGKJ202, IGKC01	V-DOMAIN V-KAPPA, C-DOMAIN C-KAPPA	IG	FAB-GAMMA-1_KAPPA	IMGT (202640-0)

SAbDab Antibody Annotation SAbDab Database Homepage

Chain	Chain Class	Chain Subclass	Chain Type	Antigen Name(s)	Provenance Source
G, H, J, S, U, G, H, J, S, U, W [auth X]	Heavy Chain	IGHV1	-	hemagglutinin ha2 \| hemagglutinin ha1 \| hemagglutinin ha1, hemagglutinin ha2, hemagglutinin ha2 \| hemagglutinin ha1	SAbDab (2026-10-16)
I, K, L, T, V, I, K, L, T, V, X [auth Y]	Light Chain	IGKV1	Kappa	hemagglutinin ha2 \| hemagglutinin ha1 \| hemagglutinin ha1, hemagglutinin ha2 \| hemagglutinin ha1, hemagglutinin ha2	SAbDab (2026-10-16)

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
B, D, F, N, P B, D, F, N, P, R	Hemagglutinin HA2	host cell surface binding 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 membrane organization cellular component organization membrane fusion fusion of virus membrane with host plasma membrane cellular process cellular component organization or biogenesis virion attachment to host cell biological process involved in interspecies interaction between organisms adhesion of symbiont to host cell viral life cycle adhesion of symbiont to host 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 fusion of virus membrane with host plasma membrane cellular process cellular component organization or biogenesis virion attachment to host cell biological process involved in interspecies interaction between organisms 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 non-lytic viral release viral budding virion assembly exit from host cell viral budding from plasma membrane viral release from host cell import into cell receptor-mediated endocytosis of virus by host cell transport establishment of localization vesicle-mediated transport localization symbiont entry into host cell clathrin-dependent endocytosis symbiont entry into host clathrin-dependent endocytosis of virus by host cell receptor-mediated endocytosis endocytosis endocytosis involved in viral entry into host cell	cellular anatomical structure membrane virion component virion membrane viral membrane viral envelope host cell plasma membrane host cellular component host cell part host cell membrane other organism part
G, H, J, S, U, G, H, J, S, U, W [auth X]	16.a.26 Heavy chain	-	-	-
I, K, L, T, V, I, K, L, T, V, X [auth Y]	16.a.26 Light chain	-	-	-
A, C, E, M, O A, C, E, M, O, Q	Hemagglutinin HA1	host cell surface binding 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 membrane organization cellular component organization membrane fusion fusion of virus membrane with host plasma membrane cellular process cellular component organization or biogenesis virion attachment to host cell biological process involved in interspecies interaction between organisms adhesion of symbiont to host cell viral life cycle adhesion of symbiont to host 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 fusion of virus membrane with host plasma membrane cellular process cellular component organization or biogenesis virion attachment to host cell biological process involved in interspecies interaction between organisms 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 non-lytic viral release viral budding virion assembly exit from host cell viral budding from plasma membrane viral release from host cell import into cell receptor-mediated endocytosis of virus by host cell transport establishment of localization vesicle-mediated transport localization symbiont entry into host cell clathrin-dependent endocytosis symbiont entry into host clathrin-dependent endocytosis of virus by host cell receptor-mediated endocytosis endocytosis endocytosis involved in viral entry into host cell	cellular anatomical structure membrane virion component virion membrane viral membrane viral envelope host cell plasma membrane host cellular component host cell part host cell membrane other organism part

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
B, D, F, N, P B, D, F, N, P, R	IPR001364	Haemagglutinin, influenzavirus A/B	Family
B, D, F, N, P B, D, F, N, P, R	IPR008980	Viral capsid/haemagglutinin protein	Homologous Superfamily
B, D, F, N, P B, D, F, N, P, R	IPR000149	Haemagglutinin, influenzavirus A	Family
B, D, F, N, P B, D, F, N, P, R	IPR013828	Haemagglutinin, HA1 chain, alpha/beta domain superfamily	Homologous Superfamily
A, C, E, M, O A, C, E, M, O, Q	IPR001364	Haemagglutinin, influenzavirus A/B	Family
A, C, E, M, O A, C, E, M, O, Q	IPR008980	Viral capsid/haemagglutinin protein	Homologous Superfamily
A, C, E, M, O A, C, E, M, O, Q	IPR000149	Haemagglutinin, influenzavirus A	Family
A, C, E, M, O A, C, E, M, O, Q	IPR013828	Haemagglutinin, HA1 chain, alpha/beta domain superfamily	Homologous Superfamily