7SU0

Crystal structure of an acidic pH-selective Ipilimumab variant Ipi.105 in complex with CTLA-4


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.41 Å
  • R-Value Free: 0.264 
  • R-Value Work: 0.206 
  • R-Value Observed: 0.209 

Starting Models: experimental
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Ligand Structure Quality Assessment 


This is version 1.2 of the entry. See complete history


Literature

Improved therapeutic index of an acidic pH-selective antibody.

Lee, P.S.MacDonald, K.G.Massi, E.Chew, P.V.Bee, C.Perkins, P.Chau, B.Thudium, K.Lohre, J.Nandi, P.Deyanova, E.G.Barman, I.Gudmundsson, O.Dollinger, G.Sproul, T.Engelhardt, J.J.Strop, P.Rajpal, A.

(2022) MAbs 14: 2024642-2024642

  • DOI: https://doi.org/10.1080/19420862.2021.2024642
  • Primary Citation of Related Structures:  
    7SU0, 7SU1

  • PubMed Abstract: 

    Although therapeutically efficacious, ipilimumab can exhibit dose-limiting toxicity that prevents maximal efficacious clinical outcomes and can lead to discontinuation of treatment. We hypothesized that an acidic pH-selective ipilimumab (pH Ipi), which preferentially and reversibly targets the acidic tumor microenvironment over the neutral periphery, may have a more favorable therapeutic index. While ipilimumab has pH-independent CTLA-4 affinity, pH Ipi variants have been engineered to have up to 50-fold enhanced affinity to CTLA-4 at pH 6.0 compared to pH 7.4. In hCTLA-4 knock-in mice, these variants have maintained anti-tumor activity and reduced peripheral activation, a surrogate marker for toxicity. pH-sensitive therapeutic antibodies may be a differentiating paradigm and a novel modality for enhanced tumor targeting and improved safety profiles.


  • Organizational Affiliation

    Discovery Biotherapeutics, Bristol Myers Squibb, Redwood City, CA, USA.


Macromolecules
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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Cytotoxic T-lymphocyte protein 4A [auth C],
D
125Homo sapiensMutation(s): 0 
Gene Names: CTLA4CD152
UniProt & NIH Common Fund Data Resources
Find proteins for P16410 (Homo sapiens)
Explore P16410 
Go to UniProtKB:  P16410
PHAROS:  P16410
GTEx:  ENSG00000163599 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP16410
Glycosylation
Glycosylation Sites: 2Go to GlyGen: P16410-1
Sequence Annotations
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  • Reference Sequence
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Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
Fab heavy chainB [auth H],
E [auth I]
229Homo sapiensMutation(s): 0 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Sequence Annotations
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  • Reference Sequence
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Entity ID: 3
MoleculeChains Sequence LengthOrganismDetailsImage
Fab light chainC [auth L],
F [auth M]
215Homo sapiensMutation(s): 0 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.41 Å
  • R-Value Free: 0.264 
  • R-Value Work: 0.206 
  • R-Value Observed: 0.209 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 96.73α = 90
b = 197.84β = 90
c = 146.49γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
XDSdata reduction
XSCALEdata scaling
PHASERphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Not funded--

Revision History  (Full details and data files)

  • Version 1.0: 2022-03-02
    Type: Initial release
  • Version 1.1: 2023-10-18
    Changes: Data collection, Refinement description
  • Version 1.2: 2024-10-16
    Changes: Structure summary