4K71

Crystal structure of a high affinity Human Serum Albumin variant bound to the Neonatal Fc Receptor

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.255 
  • R-Value Work: 0.212 
  • R-Value Observed: 0.214 

wwPDB Validation   3D Report Full Report


This is version 1.1 of the entry. See complete history. 


Literature

Crystal structure of an HSA/FcRn complex reveals recycling by competitive mimicry of HSA ligands at a pH-dependent hydrophobic interface.

Schmidt, M.M., Townson, S.A., Andreucci, A.J., King, B.M., Schirmer, E.B., Murillo, A.J., Dombrowski, C., Tisdale, A.W., Lowden, P.A., Masci, A.L., Kovalchin, J.T., Erbe, D.V., Wittrup, K.D., Furfine, E.S., Barnes, T.M.

(2013) Structure 21: 1966-1978

  • DOI: https://doi.org/10.1016/j.str.2013.08.022
  • Primary Citation of Related Structures:  
    4K71

  • PubMed Abstract: 

    • The long circulating half-life of serum albumin, the most abundant protein in mammalian plasma, derives from pH-dependent endosomal salvage from degradation, mediated by the neonatal Fc receptor (FcRn). Using yeast display, we identified human serum albumin (HSA) variants with increased affinity for human FcRn at endosomal pH, enabling us to solve the crystal structure of a variant HSA/FcRn complex ...

    The long circulating half-life of serum albumin, the most abundant protein in mammalian plasma, derives from pH-dependent endosomal salvage from degradation, mediated by the neonatal Fc receptor (FcRn). Using yeast display, we identified human serum albumin (HSA) variants with increased affinity for human FcRn at endosomal pH, enabling us to solve the crystal structure of a variant HSA/FcRn complex. We find an extensive, primarily hydrophobic interface stabilized by hydrogen-bonding networks involving protonated histidines internal to each protein. The interface features two key FcRn tryptophan side chains inserting into deep hydrophobic pockets on HSA that overlap albumin ligand binding sites. We find that fatty acids (FAs) compete with FcRn, revealing a clash between ligand binding and recycling, and that our high-affinity HSA variants have significantly increased circulating half-lives in mice and monkeys. These observations open the way for the creation of biotherapeutics with significantly improved pharmacokinetics.

    Organizational Affiliation: 

    Eleven Biotherapeutics, Inc., Cambridge, MA 02142, USA.



Macromolecules
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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Serum albuminA, D585Homo sapiensMutation(s): 4 
Gene Names: ALB, GIG20, GIG42, PRO0903, PRO1708, PRO2044, PRO2619, PRO2675, UNQ696/PRO1341
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Find proteins for P02768 (Homo sapiens)
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Go to UniProtKB:  P02768
PHAROS:  P02768
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UniProt GroupP02768
Protein Feature View
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Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
IgG receptor FcRn large subunit p51B, E274Homo sapiensMutation(s): 0 
Gene Names: FCGRT, FCRN
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Find proteins for P55899 (Homo sapiens)
Explore P55899 
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PHAROS:  P55899
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UniProt GroupP55899
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Entity ID: 3
MoleculeChainsSequence LengthOrganismDetailsImage
Beta-2-microglobulinC, F99Homo sapiensMutation(s): 0 
Gene Names: B2M, CDABP0092, HDCMA22P
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Find proteins for P61769 (Homo sapiens)
Explore P61769 
Go to UniProtKB:  P61769
PHAROS:  P61769
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UniProt GroupP61769
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  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4
Download Ideal Coordinates CCD File 
G [auth A],
H [auth A],
I [auth A],
J [auth A],
K [auth A],
G [auth A],
H [auth A],
I [auth A],
J [auth A],
K [auth A],
L [auth A],
M [auth A],
N [auth B],
O [auth B],
P [auth C],
Q [auth C],
R [auth D],
S [auth D],
T [auth D],
U [auth D],
V [auth D],
W [auth D],
X [auth E],
Y [auth F]
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L		 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.255 
  • R-Value Work: 0.212 
  • R-Value Observed: 0.214 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 127.893α = 90
b = 203.536β = 90
c = 100.561γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
PHASERphasing
REFMACrefinement
XDSdata reduction
XSCALEdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2013-10-23
    Type: Initial release
  • Version 1.1: 2014-02-05
    Changes: Database references