9QR9 | pdb_00009qr9

ChiLob 7/4 hIgG1 HC-K219C F(ab')2

• PDB DOI: https://doi.org/10.2210/pdb9QR9/pdb

• Classification: IMMUNE SYSTEM
• Organism(s): Homo sapiens
• Expression System: Cricetulus griseus
• Mutation(s): No 


• Deposited: 2025-04-03 Released: 2026-10-14 
• Deposition Author(s): Elliott, I.G., Tews, I., Orr, C.M.
• Funding Organization(s): Cancer Research UK

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 3.49 Å
• R-Value Free: 
  0.271 (Depositor), 0.278 (DCC) 
• R-Value Work: 
  0.206 (Depositor), 0.215 (DCC) 

Starting Model: experimental

Literature

Disulfide engineering as an approach to reduce conformational flexibility of immunostimulatory antibodies to enhance receptor agonism

Elliott, I.G., Tews, I., Orr, C.M., Fisher, H.R., Essex, J.W., Cragg, M.S.

To be published.

Biological Assembly 1  

Global Symmetry: Cyclic - C2  (Explore in 3D)
Global Stoichiometry: Hetero 4-mer - A2B2 

Biological assembly 1 assigned by authors.

Biological Assembly Evidence: electron microscopy, SAXS, mass spectrometry, gel filtration

Macromolecule Content 

• Total Structure Weight: 98.69 kDa 
• Atom Count: 6,400 
• Modeled Residue Count: 839 
• Deposited Residue Count: 910 
• Unique protein chains: 2

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
ChiLob 7/4 hIgG1 heavy chain K219C	A [auth H], C [auth A]	241	Homo sapiens	Mutation(s): 0

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
ChiLob 7/4 hIgG1 kappa light chain	B [auth L], D [auth B]	214	Homo sapiens	Mutation(s): 0

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 3.49 Å
• R-Value Free:  0.271 (Depositor), 0.278 (DCC) 
• R-Value Work:  0.206 (Depositor), 0.215 (DCC) 

Space Group: P 2₁ 2₁ 2₁

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 44.434	α = 90
b = 132.637	β = 90
c = 162.968	γ = 90

Software Package:

Software Name	Purpose
XDS	data reduction
Aimless	data scaling
autoPROC	data scaling
STARANISO	data scaling
PHASER	phasing
REFMAC	refinement
PDB-REDO	refinement
MolProbity	model building
Coot	model building

Structure Validation

Entry History 

& Funding Information

Deposition Data

• Released Date: 2026-10-14 
Deposition Author(s): Elliott, I.G., Tews, I., Orr, C.M.

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Funding Organization	Location	Grant Number
Cancer Research UK	United Kingdom	--

Revision History  

• Version 1.0: 2026-10-14
  Type: Initial release