1I1C

NON-FCRN BINDING FC FRAGMENT OF RAT IGG2A

• PDB DOI: https://doi.org/10.2210/pdb1I1C/pdb

• Classification: IMMUNE SYSTEM
• Organism(s): Rattus norvegicus
• Expression System: Cricetulus griseus
• Mutation(s): Yes 


• Deposited: 2001-01-31 Released: 2001-02-14 
• Deposition Author(s): Martin, W.L., West Jr., A.P., Gan, L., Bjorkman, P.J.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.70 Å
• R-Value Free: 0.279 
• R-Value Work: 0.241 

Literature

Crystal structure at 2.8 A of an FcRn/heterodimeric Fc complex: mechanism of pH-dependent binding.

Martin, W.L., West Jr., A.P., Gan, L., Bjorkman, P.J.

(2001) Mol Cell 7: 867-877

• PubMed: 11336709 
• DOI: https://doi.org/10.1016/s1097-2765(01)00230-1
• Primary Citation of Related Structures:  
  1I1A, 1I1C


• PubMed Abstract: 
  

  The neonatal Fc receptor (FcRn) transports immunoglobulin G (IgG) across epithelia, binding IgG in acidic vesicles (pH < or = 6.5) and releasing IgG in the blood at pH 7.4. Well-ordered FcRn/Fc crystals are prevented by the formation of "oligomeric ribbons" of FcRn dimers bridged by Fc homodimers, thus we crystallized a 1:1 complex between rat FcRn and a heterodimeric Fc containing only one FcRn binding site. The 2.8 A complex structure demonstrates that FcRn uses its alpha2 and beta2-microglobulin domains and carbohydrate to interact with the Fc C(gamma)2-C(gamma)3 interface. The structure reveals conformational changes in Fc and three titratable salt bridges that confer pH-dependent binding, and can be used to guide rational design of therapeutic IgGs with longer serum half-lives.

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Organizational Affiliation: 

Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA.

Biological Assembly 1  

Global Symmetry: Cyclic - C2  (Explore in 3D)
Global Stoichiometry: Homo 2-mer - A2 

Biological assembly 1 assigned by authors and generated by PISA (software)

Macromolecule Content

• Total Structure Weight: 56.23 kDa 
• Atom Count: 3,440 
• Modelled Residue Count: 410 
• Deposited Residue Count: 478 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
IG GAMMA-2A CHAIN C REGION	A, B	239	Rattus norvegicus	Mutation(s): 6
UniProt
Find proteins for P20760 (Rattus norvegicus) Explore P20760  Go to UniProtKB:  P20760

Oligosaccharides

Help

Entity ID: 2
Molecule	Chains	Length	2D Diagram	Glycosylation	3D Interactions
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)]beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-[beta-L-fucopyranose-(1-6)]2-acetamido-2-deoxy-beta-D-glucopyranose	C	8		N-Glycosylation
Glycosylation Resources
GlyTouCan:  G59451NL GlyCosmos:  G59451NL GlyGen:  G59451NL

Entity ID: 3
Molecule	Chains	Length	2D Diagram	Glycosylation	3D Interactions
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)]beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-[alpha-L-fucopyranose-(1-6)]2-acetamido-2-deoxy-beta-D-glucopyranose	D	8		N-Glycosylation
Glycosylation Resources
GlyTouCan:  G80858MF GlyCosmos:  G80858MF GlyGen:  G80858MF

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.70 Å
• R-Value Free: 0.279 
• R-Value Work: 0.241 
• Space Group: P 1 2₁ 1

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 42.503	α = 90
b = 73.362	β = 102.74
c = 82.157	γ = 90

Software Package:

Software Name	Purpose
DENZO	data reduction
SCALEPACK	data scaling
AMoRE	phasing
CNS	refinement

Structure Validation

Entry History 

Deposition Data

• Released Date: 2001-02-14 
Deposition Author(s): Martin, W.L., West Jr., A.P., Gan, L., Bjorkman, P.J.

Revision History  

• Version 1.0: 2001-02-14
  Type: Initial release
  
• Version 1.1: 2008-04-27
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Non-polymer description, Version format compliance
• Version 2.0: 2020-07-29
  Type: Remediation
  Reason: Carbohydrate remediation
  Changes: Advisory, Atomic model, Data collection, Database references, Derived calculations, Structure summary
• Version 2.1: 2021-10-27
  Changes: Database references, Structure summary
• Version 2.2: 2023-08-09
  Changes: Data collection, Refinement description