4HG4 | pdb_00004hg4

Crystal structure of Fab 2G1 in complex with a H2N2 influenza virus hemagglutinin

External Resource: Annotation

Domain Annotation: SCOP2 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: SCOP2 Classification SCOP2 Database Homepage

Chains	Type	Family Name	Domain Identifier	Family Identifier	Provenance Source (Version)
R [auth i]	SCOP2B Superfamily	Influenza hemagglutinin (stalk)	8087970	3001616	SCOP2B (2022-06-29)
P [auth h]	SCOP2B Superfamily	Influenza hemagglutinin (stalk)	8087970	3001616	SCOP2B (2022-06-29)
N [auth g]	SCOP2B Superfamily	Influenza hemagglutinin (stalk)	8087970	3001616	SCOP2B (2022-06-29)
L [auth f]	SCOP2B Superfamily	Influenza hemagglutinin (stalk)	8087970	3001616	SCOP2B (2022-06-29)
J [auth e]	SCOP2B Superfamily	Influenza hemagglutinin (stalk)	8087970	3001616	SCOP2B (2022-06-29)
H [auth d]	SCOP2B Superfamily	Influenza hemagglutinin (stalk)	8087970	3001616	SCOP2B (2022-06-29)
F [auth c]	SCOP2B Superfamily	Influenza hemagglutinin (stalk)	8087970	3001616	SCOP2B (2022-06-29)
D [auth b]	SCOP2B Superfamily	Influenza hemagglutinin (stalk)	8087970	3001616	SCOP2B (2022-06-29)
B [auth a]	SCOP2B Superfamily	Influenza hemagglutinin (stalk)	8087970	3001616	SCOP2B (2022-06-29)
A	SCOP2B Superfamily	Influenza hemagglutinin domain-like	8087768	3001342	SCOP2B (2022-06-29)
Q [auth I]	SCOP2B Superfamily	Influenza hemagglutinin domain-like	8087768	3001342	SCOP2B (2022-06-29)
O [auth H]	SCOP2B Superfamily	Influenza hemagglutinin domain-like	8087768	3001342	SCOP2B (2022-06-29)
M [auth G]	SCOP2B Superfamily	Influenza hemagglutinin domain-like	8087768	3001342	SCOP2B (2022-06-29)
K [auth F]	SCOP2B Superfamily	Influenza hemagglutinin domain-like	8087768	3001342	SCOP2B (2022-06-29)
I [auth E]	SCOP2B Superfamily	Influenza hemagglutinin domain-like	8087768	3001342	SCOP2B (2022-06-29)
G [auth D]	SCOP2B Superfamily	Influenza hemagglutinin domain-like	8087768	3001342	SCOP2B (2022-06-29)
E [auth C]	SCOP2B Superfamily	Influenza hemagglutinin domain-like	8087768	3001342	SCOP2B (2022-06-29)
C [auth B]	SCOP2B Superfamily	Influenza hemagglutinin domain-like	8087768	3001342	SCOP2B (2022-06-29)

Domain Annotation: ECOD Classification ECOD Database Homepage

Chains	Domain Identifier	Architecture	Possible Homology	Homology	Topology	Family	Provenance Source (Version)
Z [auth Q]	e4hg4Q1	A: HTH	X: HTH	H: winged helix domain	T: tRNA-synt_His	F:	ECOD (20:10:01)
X [auth O]	e4hg4O1	A: beta-Grasp	X: Ubiquitin-related	H: Ubiquitin-like	T: 14-3-3	F:	ECOD (20:10:01)
V [auth M]	e4hg4M1	A: Alpha-beta plaits	X: Family B DNA polymerase insertion domain	H: Family B DNA polymerase insertion domain	T: RimK	F:	ECOD (20:10:01)
T [auth K]	e4hg4K1	A: beta-Grasp	X: Ubiquitin-related	H: Ubiquitin-like	T: V-set	F:	ECOD (20:10:01)
JA [auth z]	e4hg4z1	A: Alpha-beta plaits	X: Phage tail protein-like	H: Phage tail protein-like	T: T4-gp15_tss	F:	ECOD (20:10:01)
HA [auth Y]	e4hg4Y1	A: Alpha-beta plaits	X: Family B DNA polymerase insertion domain	H: Family B DNA polymerase insertion domain	T: RimK	F:	ECOD (20:10:01)
FA [auth W]	e4hg4W1	A: beta-Grasp	X: Ubiquitin-related	H: Ubiquitin-like	T: V-set	F:	ECOD (20:10:01)
DA [auth U]	e4hg4U1	A: beta-Grasp	X: Ubiquitin-related	H: Ubiquitin-like	T: 14-3-3	F:	ECOD (20:10:01)
BA [auth S]	e4hg4S1	A: beta-Grasp	X: Ubiquitin-related	H: Ubiquitin-like	T: 14-3-3	F:	ECOD (20:10:01)
Y [auth P]	e4hg4P1	A: Lipocalins/Streptavidin	X: Enterocin 7A and 7B	H: Enterocin 7A and 7B	T:	F:	ECOD (20:10:01)
W [auth N]	e4hg4N1	A: Alpha-beta plaits	X: Family B DNA polymerase insertion domain	H: Family B DNA polymerase insertion domain	T: RimK	F:	ECOD (20:10:01)
U [auth L]	e4hg4L3	A: Subtilisin-like	X: Subtilisin-like	H: Subtilisin-like	T: V-set	F:	ECOD (20:10:01)
S [auth J]	e4hg4J1	A: beta-Grasp	X: Ubiquitin-related	H: Ubiquitin-like	T: FtsJ	F:	ECOD (20:10:01)
IA [auth Z]	e4hg4Z3	A: HTH	X: HTH	H: winged helix domain	T: tRNA-synt_His	F:	ECOD (20:10:01)
GA [auth X]	e4hg4X1	A: jelly-roll	X: Double-stranded beta-helix	H: Double-stranded beta-helix	T: RhaA	F:	ECOD (20:10:01)
EA [auth V]	e4hg4V1	A: Alpha-beta plaits	X: Family B DNA polymerase insertion domain	H: Family B DNA polymerase insertion domain	T: RimK	F:	ECOD (20:10:01)
CA [auth T]	e4hg4T1	A: beta-Grasp	X: Ubiquitin-related	H: Ubiquitin-like	T: 14-3-3	F:	ECOD (20:10:01)
AA [auth R]	e4hg4R1	A: beta-Grasp	X: Ubiquitin-related	H: Ubiquitin-like	T: 14-3-3	F:	ECOD (20:10:01)
A	e4hg4A1	A: beta-Grasp	X: Ubiquitin-related	H: Ubiquitin-like	T: 14-3-3	F:	ECOD (20:10:01)
Q [auth I]	e4hg4I1	A: beta-Grasp	X: Ubiquitin-related	H: Ubiquitin-like	T: 14-3-3	F:	ECOD (20:10:01)
O [auth H]	e4hg4H1	A: Alpha-beta plaits	X: Family B DNA polymerase insertion domain	H: Family B DNA polymerase insertion domain	T: RimK	F:	ECOD (20:10:01)
M [auth G]	e4hg4G1	A: beta-Grasp	X: Ubiquitin-related	H: Ubiquitin-like	T: 14-3-3	F:	ECOD (20:10:01)
K [auth F]	e4hg4F1	A: beta-Grasp	X: Ubiquitin-related	H: Ubiquitin-like	T: 14-3-3	F:	ECOD (20:10:01)
I [auth E]	e4hg4E1	A: beta-Grasp	X: Ubiquitin-related	H: Ubiquitin-like	T: 14-3-3	F:	ECOD (20:10:01)
G [auth D]	e4hg4D1	A: beta-Grasp	X: Ubiquitin-related	H: Ubiquitin-like	T: 14-3-3	F:	ECOD (20:10:01)
E [auth C]	e4hg4C1	A: beta-Grasp	X: Ubiquitin-related	H: Ubiquitin-like	T: 14-3-3	F:	ECOD (20:10:01)
C [auth B]	e4hg4B1	A: beta-Grasp	X: Ubiquitin-related	H: Ubiquitin-like	T: 14-3-3	F:	ECOD (20:10:01)

Domain Annotation: CATH CATH Database Homepage

Chain	Domain	Class	Architecture	Topology	Homology	Provenance Source (Version)
Z [auth Q]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
X [auth O]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
V [auth M]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
T [auth K]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
JA [auth z]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
HA [auth Y]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
FA [auth W]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
DA [auth U]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
BA [auth S]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
Y [auth P]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
W [auth N]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
U [auth L]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
S [auth J]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
IA [auth Z]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
GA [auth X]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
EA [auth V]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
CA [auth T]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
AA [auth R]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
R [auth i]	3.90.20.10	Alpha Beta	Alpha-Beta Complex	Hemagglutinin Ectodomain	Chain B	CATH (4.3.0)
P [auth h]	3.90.20.10	Alpha Beta	Alpha-Beta Complex	Hemagglutinin Ectodomain	Chain B	CATH (4.3.0)
N [auth g]	3.90.20.10	Alpha Beta	Alpha-Beta Complex	Hemagglutinin Ectodomain	Chain B	CATH (4.3.0)
L [auth f]	3.90.20.10	Alpha Beta	Alpha-Beta Complex	Hemagglutinin Ectodomain	Chain B	CATH (4.3.0)
J [auth e]	3.90.20.10	Alpha Beta	Alpha-Beta Complex	Hemagglutinin Ectodomain	Chain B	CATH (4.3.0)
H [auth d]	3.90.20.10	Alpha Beta	Alpha-Beta Complex	Hemagglutinin Ectodomain	Chain B	CATH (4.3.0)
F [auth c]	3.90.20.10	Alpha Beta	Alpha-Beta Complex	Hemagglutinin Ectodomain	Chain B	CATH (4.3.0)
D [auth b]	3.90.20.10	Alpha Beta	Alpha-Beta Complex	Hemagglutinin Ectodomain	Chain B	CATH (4.3.0)
B [auth a]	3.90.20.10	Alpha Beta	Alpha-Beta Complex	Hemagglutinin Ectodomain	Chain B	CATH (4.3.0)
A	2.10.77.10	Mainly Beta	Ribbon	Hemagglutinin	Chain A, domain 2	CATH (4.3.0)
A	3.90.209.20	Alpha Beta	Alpha-Beta Complex	Hemagglutinin (Ha1 Chain)	Chain: A	CATH (4.3.0)
Q [auth I]	2.10.77.10	Mainly Beta	Ribbon	Hemagglutinin	Chain A, domain 2	CATH (4.3.0)
Q [auth I]	3.90.209.20	Alpha Beta	Alpha-Beta Complex	Hemagglutinin (Ha1 Chain)	Chain: A	CATH (4.3.0)
O [auth H]	2.10.77.10	Mainly Beta	Ribbon	Hemagglutinin	Chain A, domain 2	CATH (4.3.0)
O [auth H]	3.90.209.20	Alpha Beta	Alpha-Beta Complex	Hemagglutinin (Ha1 Chain)	Chain: A	CATH (4.3.0)
M [auth G]	2.10.77.10	Mainly Beta	Ribbon	Hemagglutinin	Chain A, domain 2	CATH (4.3.0)
M [auth G]	3.90.209.20	Alpha Beta	Alpha-Beta Complex	Hemagglutinin (Ha1 Chain)	Chain: A	CATH (4.3.0)
K [auth F]	2.10.77.10	Mainly Beta	Ribbon	Hemagglutinin	Chain A, domain 2	CATH (4.3.0)
K [auth F]	3.90.209.20	Alpha Beta	Alpha-Beta Complex	Hemagglutinin (Ha1 Chain)	Chain: A	CATH (4.3.0)
I [auth E]	2.10.77.10	Mainly Beta	Ribbon	Hemagglutinin	Chain A, domain 2	CATH (4.3.0)
I [auth E]	3.90.209.20	Alpha Beta	Alpha-Beta Complex	Hemagglutinin (Ha1 Chain)	Chain: A	CATH (4.3.0)
G [auth D]	2.10.77.10	Mainly Beta	Ribbon	Hemagglutinin	Chain A, domain 2	CATH (4.3.0)
G [auth D]	3.90.209.20	Alpha Beta	Alpha-Beta Complex	Hemagglutinin (Ha1 Chain)	Chain: A	CATH (4.3.0)
E [auth C]	2.10.77.10	Mainly Beta	Ribbon	Hemagglutinin	Chain A, domain 2	CATH (4.3.0)
E [auth C]	3.90.209.20	Alpha Beta	Alpha-Beta Complex	Hemagglutinin (Ha1 Chain)	Chain: A	CATH (4.3.0)
C [auth B]	2.10.77.10	Mainly Beta	Ribbon	Hemagglutinin	Chain A, domain 2	CATH (4.3.0)
C [auth B]	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
BA [auth S], DA [auth U], FA [auth W], HA [auth Y], JA [auth z], BA [auth S], DA [auth U], FA [auth W], HA [auth Y], JA [auth z], T [auth K], V [auth M], X [auth O], Z [auth Q]	2G1 Fab	L-KAPPA	Homo sapiens (human)	IGKV1-3301, IGKV1D-3301, IGKJ501, IGKC01	V-DOMAIN V-KAPPA, C-DOMAIN C-KAPPA	IG	FAB-GAMMA-1_KAPPA	IMGT (202609-0)
AA [auth R], CA [auth T], EA [auth V], GA [auth X], IA [auth Z], AA [auth R], CA [auth T], EA [auth V], GA [auth X], IA [auth Z], S [auth J], U [auth L], W [auth N], Y [auth P]	2G1 Fab	VH-CH1	Homo sapiens (human)	IGHV1-6901, IGHV1-6912, IGHV1-6913, IGHV1-69D01, IGHJ502, IGHG103	V-DOMAIN VH, C-DOMAIN CH1	IG	FAB-GAMMA-1_KAPPA	IMGT (202609-0)

SAbDab Antibody Annotation SAbDab Database Homepage

Chain	Chain Class	Chain Subclass	Chain Type	Antigen Name(s)	Provenance Source
BA [auth S], DA [auth U], FA [auth W], HA [auth Y], JA [auth z], BA [auth S], DA [auth U], FA [auth W], HA [auth Y], JA [auth z], T [auth K], V [auth M], X [auth O], Z [auth Q]	Light Chain	IGKV1	Kappa	hemagglutinin ha2, hemagglutinin ha2 \| unknown	SAbDab (2026-03-13)
AA [auth R], CA [auth T], EA [auth V], GA [auth X], IA [auth Z], AA [auth R], CA [auth T], EA [auth V], GA [auth X], IA [auth Z], S [auth J], U [auth L], W [auth N], Y [auth P]	Heavy Chain	IGHV1	-	hemagglutinin ha2, hemagglutinin ha2 \| unknown	SAbDab (2026-03-13)

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
BA [auth S], DA [auth U], FA [auth W], HA [auth Y], JA [auth z], BA [auth S], DA [auth U], FA [auth W], HA [auth Y], JA [auth z], T [auth K], V [auth M], X [auth O], Z [auth Q]	Fab 2G1 light chain	-	-	-
AA [auth R], CA [auth T], EA [auth V], GA [auth X], IA [auth Z], AA [auth R], CA [auth T], EA [auth V], GA [auth X], IA [auth Z], S [auth J], U [auth L], W [auth N], Y [auth P]	Fab 2G1 heavy chain	-	-	-
B [auth a], D [auth b], F [auth c], H [auth d], J [auth e], B [auth a], D [auth b], F [auth c], H [auth d], J [auth e], L [auth f], N [auth g], P [auth h], R [auth i]	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
A, C [auth B], E [auth C], G [auth D], I [auth E], A, C [auth B], E [auth C], G [auth D], I [auth E], K [auth F], M [auth G], O [auth H], Q [auth I]	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 [auth a], D [auth b], F [auth c], H [auth d], J [auth e], B [auth a], D [auth b], F [auth c], H [auth d], J [auth e], L [auth f], N [auth g], P [auth h], R [auth i]	IPR001364	Haemagglutinin, influenzavirus A/B	Family
B [auth a], D [auth b], F [auth c], H [auth d], J [auth e], B [auth a], D [auth b], F [auth c], H [auth d], J [auth e], L [auth f], N [auth g], P [auth h], R [auth i]	IPR008980	Viral capsid/haemagglutinin protein	Homologous Superfamily
B [auth a], D [auth b], F [auth c], H [auth d], J [auth e], B [auth a], D [auth b], F [auth c], H [auth d], J [auth e], L [auth f], N [auth g], P [auth h], R [auth i]	IPR000149	Haemagglutinin, influenzavirus A	Family
B [auth a], D [auth b], F [auth c], H [auth d], J [auth e], B [auth a], D [auth b], F [auth c], H [auth d], J [auth e], L [auth f], N [auth g], P [auth h], R [auth i]	IPR013828	Haemagglutinin, HA1 chain, alpha/beta domain superfamily	Homologous Superfamily
A, C [auth B], E [auth C], G [auth D], I [auth E], A, C [auth B], E [auth C], G [auth D], I [auth E], K [auth F], M [auth G], O [auth H], Q [auth I]	IPR001364	Haemagglutinin, influenzavirus A/B	Family
A, C [auth B], E [auth C], G [auth D], I [auth E], A, C [auth B], E [auth C], G [auth D], I [auth E], K [auth F], M [auth G], O [auth H], Q [auth I]	IPR008980	Viral capsid/haemagglutinin protein	Homologous Superfamily
A, C [auth B], E [auth C], G [auth D], I [auth E], A, C [auth B], E [auth C], G [auth D], I [auth E], K [auth F], M [auth G], O [auth H], Q [auth I]	IPR000149	Haemagglutinin, influenzavirus A	Family
A, C [auth B], E [auth C], G [auth D], I [auth E], A, C [auth B], E [auth C], G [auth D], I [auth E], K [auth F], M [auth G], O [auth H], Q [auth I]	IPR013828	Haemagglutinin, HA1 chain, alpha/beta domain superfamily	Homologous Superfamily