6EDG

Pseudomonas exotoxin A domain III T18H477L


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.47 Å
  • R-Value Free: 0.192 
  • R-Value Work: 0.177 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Deimmunizing substitutions in Pseudomonasexotoxin domain III perturb antigen processing without eliminating T-cell epitopes.

Moss, D.L.Park, H.W.Mettu, R.R.Landry, S.J.

(2019) J.Biol.Chem. 294: 4667-4681

  • DOI: 10.1074/jbc.RA118.006704

  • PubMed Abstract: 
  • Effective adaptive immune responses depend on activation of CD4+ T cells via the presentation of antigen peptides in the context of major histocompatibility complex (MHC) class II. The structure of an antigen strongly influences its processing within ...

    Effective adaptive immune responses depend on activation of CD4+ T cells via the presentation of antigen peptides in the context of major histocompatibility complex (MHC) class II. The structure of an antigen strongly influences its processing within the endolysosome and potentially controls the identity of peptides that are presented to T cells. A recombinant immunotoxin, comprising exotoxin A domain III (PE-III) from Pseudomonas aeruginosa and a cancer-specific antibody fragment, has been developed to manage cancer, but its effectiveness is limited by the induction of neutralizing antibodies. Here, we observed that this immunogenicity is substantially reduced by substituting six residues within PE-III. Although these substitutions targeted T-cell epitopes, we demonstrate that reduced conformational stability and protease resistance were responsible for the reduced antibody titer. Analysis of mouse T-cell responses coupled with biophysical studies on single-substitution versions of PE-III suggested that modest but comprehensible changes in T-cell priming can dramatically perturb antibody production. The most strongly responsive PE-III epitope was well-predicted by a structure-based algorithm. In summary, single-residue substitutions can drastically alter the processing and immunogenicity of PE-III but have only modest effects on CD4+ T-cell priming in mice. Our findings highlight the importance of structure-based processing constraints for accurate epitope prediction.


    Organizational Affiliation

    the Department of Computer Science, Tulane University, New Orleans, Louisiana 70118.,From the Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, Louisiana 70112 and landry@tulane.edu.,From the Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, Louisiana 70112 and.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Exotoxin
A
213Pseudomonas aeruginosaMutation(s): 5 
Find proteins for A0A509JAV1 (Pseudomonas aeruginosa)
Go to UniProtKB:  A0A509JAV1
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
P34
Query on P34

Download SDF File 
Download CCD File 
A
N~2~,N~2~-DIMETHYL-N~1~-(6-OXO-5,6-DIHYDROPHENANTHRIDIN-2-YL)GLYCINAMIDE
C17 H17 N3 O2
UYJZZVDLGDDTCL-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.47 Å
  • R-Value Free: 0.192 
  • R-Value Work: 0.177 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 38.373α = 90.00
b = 48.188β = 90.00
c = 99.002γ = 90.00
Software Package:
Software NamePurpose
SCALAdata scaling
REFMACrefinement
XDSdata reduction
MOLREPphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute Of Allergy and Infectious DiseasesUnited StatesR21-AI122199

Revision History 

  • Version 1.0: 2019-02-06
    Type: Initial release
  • Version 1.1: 2019-08-21
    Type: Data collection, Database references