5DUQ

Active human c1-inhibitor in complex with dextran sulfate


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.90 Å
  • R-Value Free: 0.278 
  • R-Value Work: 0.228 
  • R-Value Observed: 0.231 

wwPDB Validation 3D Report Full Report



Literature

How Dextran Sulfate Affects C1-inhibitor Activity: A Model for Polysaccharide Potentiation.

Dijk, M.Holkers, J.Voskamp, P.Giannetti, B.M.Waterreus, W.J.van Veen, H.A.Pannu, N.S.

(2016) Structure 24: 2182-2189

  • DOI: 10.1016/j.str.2016.09.013
  • Structures With Same Primary Citation

  • PubMed Abstract: 
  • C1-inhibitor is a key inhibitor of the complement and contact activation systems, and mutations in the protein can cause hereditary angioedema. Through an unknown mechanism, polysaccharides can increase C1-inhibitor activity against some of its targe ...

    C1-inhibitor is a key inhibitor of the complement and contact activation systems, and mutations in the protein can cause hereditary angioedema. Through an unknown mechanism, polysaccharides can increase C1-inhibitor activity against some of its target proteases. Here we present the crystal structures of the serine protease inhibitor (serpin) domain of active C1-inhibitor by itself and in complex with dextran sulfate. Unlike previously described interactions of serpins with polysaccharides, the structures and isothermal titration calorimetry experiments together reveal that dextran sulfate binds to C1-inhibitor's F1 helix with low affinity and does not invoke an allosteric change. Furthermore, one dextran sulfate molecule can bind multiple C1-inhibitor molecules. We propose that in a C1-inhibitor/protease/polysaccharide ternary complex, negatively charged polysaccharides link C1-inhibitor's positively charged F1 helix to positively charged autolysis loops of proteases. The proposed mechanism elegantly explains previous experiments showing that polysaccharide potentiation is increased against proteases with a greater positive charge in their autolysis loop.


    Organizational Affiliation

    Department of Biophysical Structural Chemistry, Gorlaeus Laboratories, Leiden University, Einsteinweg 55, 2333 CC Leiden, the Netherlands. Electronic address: raj@chem.leidenuniv.nl.



Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Plasma protease C1 inhibitorA, B383Homo sapiensMutation(s): 0 
Gene Names: SERPING1C1INC1NH
Find proteins for P05155 (Homo sapiens)
Explore P05155 
Go to UniProtKB:  P05155
NIH Common Fund Data Resources
PHAROS  P05155
Protein Feature View
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  • Reference Sequence
Oligosaccharides
Entity ID: 2
MoleculeChainsChain Length2D Diagram Glycosylation
beta-D-glucopyranose-(1-4)-alpha-D-glucopyranose
C
2 N/A
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NAG
Query on NAG

Download CCD File 
A, B
2-acetamido-2-deoxy-beta-D-glucopyranose
C8 H15 N O6
OVRNDRQMDRJTHS-FMDGEEDCSA-N
 Ligand Interaction
GLC
Query on GLC

Download CCD File 
A
alpha-D-glucopyranose
C6 H12 O6
WQZGKKKJIJFFOK-DVKNGEFBSA-N
 Ligand Interaction
SO3
Query on SO3

Download CCD File 
B
SULFITE ION
O3 S
LSNNMFCWUKXFEE-UHFFFAOYSA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.90 Å
  • R-Value Free: 0.278 
  • R-Value Work: 0.228 
  • R-Value Observed: 0.231 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 112.1α = 90
b = 197.424β = 103.31
c = 56.779γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
XDSdata reduction
Aimlessdata scaling
MOLREPphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2016-08-31
    Type: Initial release
  • Version 1.1: 2017-01-25
    Changes: Database references
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Atomic model, Data collection, Derived calculations, Structure summary