Crystal structure of the Fab fragment of the human HIV-1 neutralizing antibody PGZL1.H4K3 in complex with its MPER peptide epitope (region 671-683 of HIV-1 gp41).
Domain Annotation: ECOD Classification ECOD Database Homepage
| Chains | Family Name | Domain Identifier | Architecture | Possible Homology | Homology | Topology | Family | Provenance Source (Version) | 
|---|---|---|---|---|---|---|---|---|
| B [auth H] | C1-set_1 | e6o3lH1 | A: beta sandwiches | X: Immunoglobulin-like beta-sandwich | H: Immunoglobulin-related | T: Immunoglobulin/Fibronectin type III/E set domains/PapD-like | F: C1-set_1 | ECOD (1.6) | 
| B [auth H] | V-set_12 | e6o3lH2 | A: beta sandwiches | X: Immunoglobulin-like beta-sandwich | H: Immunoglobulin-related | T: Immunoglobulin/Fibronectin type III/E set domains/PapD-like | F: V-set_12 | ECOD (1.6) | 
| D [auth A] | C1-set_1 | e6o3lA1 | A: beta sandwiches | X: Immunoglobulin-like beta-sandwich | H: Immunoglobulin-related | T: Immunoglobulin/Fibronectin type III/E set domains/PapD-like | F: C1-set_1 | ECOD (1.6) | 
| D [auth A] | V-set_12 | e6o3lA2 | A: beta sandwiches | X: Immunoglobulin-like beta-sandwich | H: Immunoglobulin-related | T: Immunoglobulin/Fibronectin type III/E set domains/PapD-like | F: V-set_12 | ECOD (1.6) | 
| A [auth L] | C1-set_4 | e6o3lL1 | A: beta sandwiches | X: Immunoglobulin-like beta-sandwich | H: Immunoglobulin-related | T: Immunoglobulin/Fibronectin type III/E set domains/PapD-like | F: C1-set_4 | ECOD (1.6) | 
| A [auth L] | V-set | e6o3lL2 | A: beta sandwiches | X: Immunoglobulin-like beta-sandwich | H: Immunoglobulin-related | T: Immunoglobulin/Fibronectin type III/E set domains/PapD-like | F: V-set | ECOD (1.6) | 
| C [auth B] | C1-set_4 | e6o3lB1 | A: beta sandwiches | X: Immunoglobulin-like beta-sandwich | H: Immunoglobulin-related | T: Immunoglobulin/Fibronectin type III/E set domains/PapD-like | F: C1-set_4 | ECOD (1.6) | 
| C [auth B] | V-set | e6o3lB2 | A: beta sandwiches | X: Immunoglobulin-like beta-sandwich | H: Immunoglobulin-related | T: Immunoglobulin/Fibronectin type III/E set domains/PapD-like | F: V-set | ECOD (1.6) | 
Domain Annotation: CATH CATH Database Homepage
| Chain | Domain | Class | Architecture | Topology | Homology | Provenance Source (Version) | 
|---|---|---|---|---|---|---|
| B [auth H] | 2.60.40.10 | Mainly Beta | Sandwich | Immunoglobulin-like | Immunoglobulins | CATH (utative) | 
| D [auth A] | 2.60.40.10 | Mainly Beta | Sandwich | Immunoglobulin-like | Immunoglobulins | CATH (utative) | 
| A [auth L] | 2.60.40.10 | Mainly Beta | Sandwich | Immunoglobulin-like | Immunoglobulins | CATH (utative) | 
| C [auth B] | 2.60.40.10 | Mainly Beta | Sandwich | Immunoglobulin-like | Immunoglobulins | CATH (utative) | 
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 | 
|---|---|---|---|---|---|---|---|---|
|  B [auth H], D [auth A]  | Fab PGZL1.H4K3, anti-gp41 [HIV-1], neutralizing | VH-CH1 | Homo sapiens (human) | IGHV1-69*01, IGHV1-69*06, IGHV1-69*10, IGHV1-69*12, IGHV1-69*13, IGHV1-69*14, IGHV1-69D*01, IGHV1-69*17, IGHJ1*01, IGHJ4*01, IGHJ5*01, IGHJ5*02, IGHJ4*02, IGHJ4*03, IGHG1*01, IGHG1*02, IGHG1*04, IGHG1*05, IGHG1*12, IGHG1*14, IGHG1*13, IGHG1*09, IGHG1*10, IGHG1*07, IGHG1*11 | V-DOMAIN VH, C-DOMAIN CH1 | IG | FAB-GAMMA-1_KAPPA | IMGT (202541-0) | 
|  A [auth L], C [auth B]  | Fab PGZL1.H4K3, anti-gp41 [HIV-1], neutralizing | L-KAPPA | Homo sapiens (human) | IGKV3-20*01, IGKJ5*01, IGKC*01 | V-DOMAIN V-KAPPA, C-DOMAIN C-KAPPA | IG | FAB-GAMMA-1_KAPPA | IMGT (202541-0) | 
SAbDab Antibody Annotation SAbDab Database Homepage
| Chain | Chain Class | Chain Subclass | Chain Type | Antigen Name(s) | Provenance Source | 
|---|---|---|---|---|---|
|  B [auth H], D [auth A]  | Heavy Chain | IGHV1 | - | mper peptide, region 671-683 of hiv-1 gp41 | SAbDab (2025-10-24) | 
|  A [auth L], C [auth B]  | Light Chain | IGKV3 | Kappa | mper peptide, region 671-683 of hiv-1 gp41 | SAbDab (2025-10-24) | 
Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage
InterPro: Protein Family Classification InterPro Database Homepage
| Chains | Accession | Name | Type | 
|---|---|---|---|
| E [auth D], F [auth E]  | IPR000777 | Human immunodeficiency virus 1, envelope glycoprotein Gp120 | Domain | 
| E [auth D], F [auth E]  | IPR036377 | Gp120 core superfamily | Homologous Superfamily | 
| E [auth D], F [auth E]  | IPR000328 | Retroviral envelope protein GP41-like | Domain | 
| E [auth D], F [auth E]  | IPR037527 | Envelope glycoprotein Gp160 | Family | 














