1NZI

Crystal Structure of the CUB1-EGF Interaction Domain of Complement Protease C1s


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.5 Å
  • R-Value Free: 0.234 
  • R-Value Work: 0.216 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

X-ray structure of the Ca2+-binding interaction domain of C1s. Insights into the assembly of the C1 complex of complement

Gregory, L.A.Thielens, N.M.Arlaud, G.J.Fontecilla-Camps, J.C.Gaboriaud, C.

(2003) J.Biol.Chem. 278: 32157-32164

  • DOI: 10.1074/jbc.M305175200

  • PubMed Abstract: 
  • C1, the complex that triggers the classical pathway of complement, is assembled from two modular proteases C1r and C1s and a recognition protein C1q. The N-terminal CUB1-EGF segments of C1r and C1s are key elements of the C1 architecture, because the ...

    C1, the complex that triggers the classical pathway of complement, is assembled from two modular proteases C1r and C1s and a recognition protein C1q. The N-terminal CUB1-EGF segments of C1r and C1s are key elements of the C1 architecture, because they mediate both Ca2+-dependent C1r-C1s association and interaction with C1q. The crystal structure of the interaction domain of C1s has been solved and refined to 1.5 A resolution. The structure reveals a head-to-tail homodimer involving interactions between the CUB1 module of one monomer and the epidermal growth factor (EGF) module of its counterpart. A Ca2+ ion is bound to each EGF module and stabilizes both the intra- and inter-monomer interfaces. Unexpectedly, a second Ca2+ ion is bound to the distal end of each CUB1 module, through six ligands contributed by Glu45, Asp53, Asp98, and two water molecules. These acidic residues and Tyr17 are conserved in approximately two-thirds of the CUB repertoire and define a novel, Ca2+-binding CUB module subset. The C1s structure was used to build a model of the C1r-C1s CUB1-EGF heterodimer, which in C1 connects C1r to C1s and mediates interaction with C1q. A structural model of the C1q/C1r/C1s interface is proposed, where the rod-like collagen triple helix of C1q is accommodated into a groove along the transversal axis of the C1r-C1s heterodimer.


    Organizational Affiliation

    Laboratoire de Cristallographie et Cristallogénèse des Protéines, Institut de Biologie Structurale Jean-Pierre Ebel, 41 rue Jules Horowitz, 38027 Grenoble Cedex 1, France.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Complement C1s component
A, B
159Homo sapiensGene Names: C1S
EC: 3.4.21.42
Find proteins for P09871 (Homo sapiens)
Go to Gene View: C1S
Go to UniProtKB:  P09871
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CA
Query on CA

Download SDF File 
Download CCD File 
A, B
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
MG
Query on MG

Download SDF File 
Download CCD File 
A, B
MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.5 Å
  • R-Value Free: 0.234 
  • R-Value Work: 0.216 
  • Space Group: P 1
Unit Cell:
Length (Å)Angle (°)
a = 35.134α = 87.74
b = 47.499β = 78.04
c = 56.679γ = 75.67
Software Package:
Software NamePurpose
CNSrefinement
CNSphasing
CCP4data scaling
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2003-06-10
    Type: Initial release
  • Version 1.1: 2008-04-29
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance