2ODP

Complement component C2a, the catalytic fragment of C3- and C5-convertase of human complement


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.207 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

The crystal structure of c2a, the catalytic fragment of classical pathway c3 and c5 convertase of human complement.

Krishnan, V.Xu, Y.Macon, K.Volanakis, J.E.Narayana, S.V.

(2007) J.Mol.Biol. 367: 224-233

  • DOI: 10.1016/j.jmb.2006.12.039
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • The multi-domain serine protease C2 provides the catalytic activity for the C3 and C5- convertases of the classical and lectin pathways of complement activation. Formation of these convertases requires the Mg(2+)-dependent binding of C2 to C4b, and t ...

    The multi-domain serine protease C2 provides the catalytic activity for the C3 and C5- convertases of the classical and lectin pathways of complement activation. Formation of these convertases requires the Mg(2+)-dependent binding of C2 to C4b, and the subsequent cleavage of C2 by C1s or MASP2, respectively. The C-terminal fragment C2a consisting of a serine protease (SP) and a von Willebrand factor type A (vWFA) domain, remains attached to C4b, forming the C3 convertase, C4b2a. Here, we present the crystal structure of Mg(2+)-bound C2a to 1.9 A resolution in comparison to its homolog Bb, the catalytic subunit of the alternative pathway C3 convertase, C3bBb. Although the overall domain arrangement of C2a is similar to Bb, there are certain structural differences. Unexpectedly, the conformation of the metal ion-dependent adhesion site and the position of the alpha7 helix of the vWFA domain indicate a co-factor-bound or open conformation. The active site of the SP domain is in a zymogen-like inactive conformation. On the basis of these structural features, we suggest a model for the initial steps of C3 convertase assembly.


    Organizational Affiliation

    Center for Biophysical Sciences and Engineering, School of Optometry, University of Alabama at Birmingham, Birmingham, AL 35294, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Complement C2
A
509Homo sapiensMutation(s): 1 
Gene Names: C2
Find proteins for Q5JP69 (Homo sapiens)
Go to Gene View: C2
Go to UniProtKB:  Q5JP69
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
MG
Query on MG

Download SDF File 
Download CCD File 
A
MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
 Ligand Interaction
NAG
Query on NAG

Download SDF File 
Download CCD File 
A
N-ACETYL-D-GLUCOSAMINE
C8 H15 N O6
OVRNDRQMDRJTHS-FMDGEEDCSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.207 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 51.398α = 90.00
b = 83.819β = 92.10
c = 75.243γ = 90.00
Software Package:
Software NamePurpose
HKL-2000data reduction
HKL-2000data scaling
REFMACrefinement
CNSphasing
PDB_EXTRACTdata extraction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2007-02-06
    Type: Initial release
  • Version 1.1: 2008-05-01
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Non-polymer description, Version format compliance