Biological Assembly 1  

 3D View: Structure | Electron Density | Ligand Interaction

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Hetero 3-mer - A2B1 

Biological assembly 1 assigned by authors.

Biological Assembly 2  

 3D View: Structure | Electron Density | Ligand Interaction

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Hetero 3-mer - A2B1 

Biological assembly 2 assigned by authors and generated by PISA (software)

Macromolecule Content

• Total Structure Weight: 79.02 kDa 
• Atom Count: 5163 
• Modelled Residue Count: 586 
• Deposited Residue Count: 654 
• Unique protein chains: 2

3SGK

Unique carbohydrate/carbohydrate interactions are required for high affinity binding of FcgIII and antibodies lacking core fucose

• DOI: 10.2210/pdb3SGK/pdb

• Classification: IMMUNE SYSTEM
• Organism(s): Homo sapiens
• Expression System: Cricetulus griseus, Homo sapiens
• Mutation(s): Yes 


• Deposited: 2011-06-15 Released: 2011-08-03 
• Deposition Author(s): Ferrara, C., Grau, S., Jaeger, C., Sondermann, P., Bruenker, P., Waldhauer, I., Hennig, M., Ruf, A., Rufer, A.C., Stihle, M., Umana, P., Benz, J.

---

Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.40 Å
• R-Value Free: 0.250 
• R-Value Work: 0.205 
• R-Value Observed: 0.207 

Literature

Unique carbohydrate-carbohydrate interactions are required for high affinity binding between FcgammaRIII and antibodies lacking core fucose.

Ferrara, C., Grau, S., Jager, C., Sondermann, P., Brunker, P., Waldhauer, I., Hennig, M., Ruf, A., Rufer, A.C., Stihle, M., Umana, P., Benz, J.

(2011) Proc Natl Acad Sci U S A 108: 12669-12674

• PubMed: 21768335 
• DOI: 10.1073/pnas.1108455108
• Primary Citation of Related Structures:  
  3SGJ, 3SGK


• PubMed Abstract: 
  

Antibody-mediated cellular cytotoxicity (ADCC), a key immune effector mechanism, relies on the binding of antigen-antibody complexes to Fcγ receptors expressed on immune cells. Antibodies lacking core fucosylation show a large increase in affinity for FcγRIIIa leading to an improved receptor-mediated effector function. Although afucosylated IgGs exist naturally, a next generation of recombinant therapeutic, glycoenginereed antibodies is currently being developed to exploit this finding. In this study, the crystal structures of a glycosylated Fcγ receptor complexed with either afucosylated or fucosylated Fc were determined allowing a detailed, molecular understanding of the regulatory role of Fc-oligosaccharide core fucosylation in improving ADCC. The structures reveal a unique type of interface consisting of carbohydrate-carbohydrate interactions between glycans of the receptor and the afucosylated Fc. In contrast, in the complex structure with fucosylated Fc, these contacts are weakened or nonexistent, explaining the decreased affinity for the receptor. These findings allow us to understand the higher efficacy of therapeutic antibodies lacking the core fucose and also suggest a unique mechanism by which the immune system can regulate antibody-mediated effector functions.

---

Organizational Affiliation: 

Pharma Research and Early Development, Roche Glycart AG, CH-8952 Schlieren, Switzerland.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Fc fragment	A, B	225	Homo sapiens	Mutation(s): 0  Gene Names: IGHG1
Find proteins for P01857 (Homo sapiens) Explore P01857  Go to UniProtKB:  P01857
NIH Common Fund Data Resources
PHAROS:  P01857 GTEx:  ENSG00000211896

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
human Fcg3a receptor	C	204	Homo sapiens	Mutation(s): 3  Gene Names: FCGR3A, CD16A, FCG3, FCGR3, IGFR3
Find proteins for P08637 (Homo sapiens) Explore P08637  Go to UniProtKB:  P08637
NIH Common Fund Data Resources
PHAROS:  P08637 GTEx:  ENSG00000203747

Oligosaccharides

Help

Entity ID: 3
Molecule	Chains	Chain Length	2D Diagram	Glycosylation
2-acetamido-2-deoxy-beta-D-glucopyranose-(1-2)-alpha-D-mannopyranose-(1-3)-[2-acetamido-2-deoxy-beta-D-glucopyranose-(1-2)-alpha-D-mannopyranose-(1-6)][2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)]beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose	D, E	8		N-Glycosylation

Entity ID: 4
Molecule	Chains	Chain Length	2D Diagram	Glycosylation
alpha-D-mannopyranose-(1-2)-alpha-D-mannopyranose-(1-3)-[alpha-D-mannopyranose-(1-3)-[alpha-D-mannopyranose-(1-6)]alpha-D-mannopyranose-(1-6)]beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose	F	8		N-Glycosylation

Entity ID: 5
Molecule	Chains	Chain Length	2D Diagram	Glycosylation
2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose	G	2		N-Glycosylation

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
MLI	A	MALONATE ION C3 H2 O4 OFOBLEOULBTSOW-UHFFFAOYSA-L

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.40 Å
• R-Value Free: 0.250 
• R-Value Work: 0.205 
• R-Value Observed: 0.207 
• Space Group: P 2₁ 2₁ 2₁

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 67.343	α = 90
b = 88.227	β = 90
c = 141.133	γ = 90

Software Package:

Software Name	Purpose
XDS	data scaling
PHASER	phasing
REFMAC	refinement
XDS	data reduction
SADABS	data scaling

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2011-06-15 
• Released Date: 2011-08-03 
Deposition Author(s): Ferrara, C., Grau, S., Jaeger, C., Sondermann, P., Bruenker, P., Waldhauer, I., Hennig, M., Ruf, A., Rufer, A.C., Stihle, M., Umana, P., Benz, J.

Revision History  

• Version 1.0: 2011-08-03
  Type: Initial release
  
• Version 1.1: 2012-04-04
  Changes: Database references
• Version 2.0: 2020-07-29
  Type: Remediation
  Reason: Carbohydrate remediation
  Changes: Advisory, Atomic model, Data collection, Database references, Derived calculations, Structure summary