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PDBsum entry 6tcp

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protein ligands Protein-protein interface(s) links
Immune system PDB id
6tcp

 

 

 

 

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Contents
Protein chains
217 a.a.
215 a.a.
Ligands
SO4 ×11
GOL ×11
PEG
Waters ×299
PDB id:
6tcp
Name: Immune system
Title: Crystal structure of the omalizumab fab leu158pro light chain mutant - crystal form ii
Structure: Omalizumab fab leu158pro light chain mutant. Chain: l, a, c, e. Engineered: yes. Other_details: omalizumab fab leu158pro light chain mutant. Omalizumab fab leu158pro light chain mutant. Chain: h, b, d, f. Engineered: yes. Other_details: omalizumab fab heavy chain
Source: Homo sapiens. Human. Organism_taxid: 9606. Expressed in: homo sapiens. Expression_system_taxid: 9606. Expression_system_cell_line: hek. Expression_system_cell_line: hek
Resolution:
2.50Å     R-factor:   0.214     R-free:   0.239
Authors: A.N.Mitropoulou,T.Ceska,A.J.Beavil,A.J.Henry,J.M.Mcdonnell, B.J.Sutton,A.M.Davies
Key ref: A.N.Mitropoulou et al. (2020). Engineering the Fab fragment of the anti-IgE omalizumab to prevent Fab crystallization and permit IgE-Fc complex crystallization. Acta Crystallogr F Struct Biol Commun, 76, 116-129. PubMed id: 32133997 DOI: 10.1107/S2053230X20001466
Date:
06-Nov-19     Release date:   18-Mar-20    
PROCHECK
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 Headers
 References

Protein chains
No UniProt id for this chain
Struc: 217 a.a.
Protein chains
No UniProt id for this chain
Struc: 215 a.a.
Key:    Secondary structure

 

 
DOI no: 10.1107/S2053230X20001466 Acta Crystallogr F Struct Biol Commun 76:116-129 (2020)
PubMed id: 32133997  
 
 
Engineering the Fab fragment of the anti-IgE omalizumab to prevent Fab crystallization and permit IgE-Fc complex crystallization.
A.N.Mitropoulou, T.Ceska, J.T.Heads, A.J.Beavil, A.J.Henry, J.M.McDonnell, B.J.Sutton, A.M.Davies.
 
  ABSTRACT  
 
Immunoglobulin E (IgE) plays a central role in the allergic response, in which cross-linking of allergen by FcεRI-bound IgE triggers mast cell and basophil degranulation and the release of inflammatory mediators. The high-affinity interaction between IgE and FcεRI is a long-standing target for therapeutic intervention in allergic disease. Omalizumab is a clinically approved anti-IgE monoclonal antibody that binds to free IgE, also with high affinity, preventing its interaction with FcεRI. All attempts to crystallize the pre-formed complex between the omalizumab Fab and the Fc region of IgE (IgE-Fc), to understand the structural basis for its mechanism of action, surprisingly failed. Instead, the Fab alone selectively crystallized in different crystal forms, but their structures revealed intermolecular Fab/Fab interactions that were clearly strong enough to disrupt the Fab/IgE-Fc complexes. Some of these interactions were common to other Fab crystal structures. Mutations were therefore designed to disrupt two recurring packing interactions observed in the omalizumab Fab crystal structures without interfering with the ability of the omalizumab Fab to recognize IgE-Fc; this led to the successful crystallization and subsequent structure determination of the Fab/IgE-Fc complex. The mutagenesis strategy adopted to achieve this result is applicable to other intractable Fab/antigen complexes or systems in which Fabs are used as crystallization chaperones.
 

 

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