Biological Assembly 1  

 3D View: Structure | Electron Density

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

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

Macromolecule Content

• Total Structure Weight: 23.71 kDa 
• Atom Count: 1612 
• Residue Count: 188 
• Unique protein chains: 1

3ERB

The Crystal Structure of C2b, a Fragment of Complement Component C2 produced during C3-convertase Formation

• DOI: 10.2210/pdb3ERB/pdb

• Classification: HYDROLASE
• Organism(s): Homo sapiens
• Expression System: Trichoplusia ni
• Mutation(s): No 


• Deposited: 2008-10-01 Released: 2009-03-10 
• Deposition Author(s): Narayan, S.V.L., Krishnan, V.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 1.80 Å
• R-Value Free: 0.240 
• R-Value Work: 0.214 
• R-Value Observed: 0.216 

Literature

The structure of C2b, a fragment of complement component C2 produced during C3 convertase formation

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

(2009) Acta Crystallogr D Biol Crystallogr 65: 266-274

• PubMed: 19237749 
• DOI: 10.1107/S0907444909000389
• Primary Citation of Related Structures:  
  3ERB


• PubMed Abstract: 
  

The second component of complement (C2) is a multi-domain serine protease that provides catalytic activity for the C3 and C5 convertases of the classical and lectin pathways of human complement. The 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 crystal structure of full-length C2 is not yet available, although the structure of its C-terminal catalytic segment C2a has been determined. The crystal structure of the N-terminal segment C2b of C2 determined to 1.8 A resolution presented here reveals the arrangement of its three CCP domains. The domains are arranged differently compared with most other CCP-domain assemblies, but their arrangement is similar to that found in the Ba part of the full-length factor B structure. The crystal structures of C2a, C2b and full-length factor B are used to generate a model for C2 and a discussion of the domain association and possible interactions with C4b during formation of the C4b-C2 complex is presented. The results of this study also suggest that upon cleavage by C1s, C2a domains undergo conformational rotation while bound to C4b and the released C2b domains may remain folded together similar to as observed in the intact protein.

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Organizational Affiliation: 

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

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Complement C2	A	223	Homo sapiens	Mutation(s): 0  Gene Names: C2 EC: 3.4.21.43
Find proteins for P06681 (Homo sapiens) Explore P06681  Go to UniProtKB:  P06681
NIH Common Fund Data Resources
PHAROS:  P06681 GTEx:  ENSG00000166278

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 1.80 Å
• R-Value Free: 0.240 
• R-Value Work: 0.214 
• R-Value Observed: 0.216 
• Space Group: P 3₁

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 60.06	α = 90
b = 60.06	β = 90
c = 61.687	γ = 120

Software Package:

Software Name	Purpose
CNS	refinement
REFMAC	refinement
d*TREK	data reduction
d*TREK	data scaling
CNS	phasing

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2008-10-01 
• Released Date: 2009-03-10 
Deposition Author(s): Narayan, S.V.L., Krishnan, V.

Revision History 

• Version 1.0: 2009-03-10
  Type: Initial release
  
• Version 1.1: 2011-07-13
  Changes: Version format compliance