2I6Q

Complement component C2a


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å
  • R-Value Free: 0.240 
  • R-Value Work: 0.189 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structure of complement component c2a: implications for convertase formation and substrate binding.

Milder, F.J.Raaijmakers, H.C.Vandeputte, M.D.Schouten, A.Huizinga, E.G.Romijn, R.A.Hemrika, W.Roos, A.Daha, M.R.Gros, P.

(2006) Structure 14: 1587-1597

  • DOI: 10.1016/j.str.2006.08.008
  • Primary Citation of Related Structures:  2I6S

  • PubMed Abstract: 
  • C2a provides the catalytic center to the convertase complexes of the classical and lectin-binding pathways of complement activation. We determined two crystal structures of full-length C2a, with and without a pseudo ligand bound. Both structures reve ...

    C2a provides the catalytic center to the convertase complexes of the classical and lectin-binding pathways of complement activation. We determined two crystal structures of full-length C2a, with and without a pseudo ligand bound. Both structures reveal a near-active conformation of the catalytic center of the serine protease domains, while the von Willebrand factor A-type domains display an intermediate activation state of helix alpha7 with an open, activated metal-ion-dependent adhesion site. The open adhesion site likely serves to enhance the affinity for the ligand C4b, similar to "inside-out" signaling in integrins. Surprisingly, the N-terminal residues of C2a are buried in a crevice near helix alpha7, indicative of a structural switch between C2 and C2a. Extended loops on the protease domain possibly envelop the protruding anaphylatoxin domain of the substrate C3. Together with a putative substrate-induced completion of the oxyanion hole, this may contribute to the high substrate specificity of the convertases.


    Organizational Affiliation

    Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Faculty of Science, Utrecht University, 3584 CH Utrecht, The Netherlands.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Complement C2a fragment
A
517Homo sapiensN/A
Find proteins for Q53HP3 (Homo sapiens)
Go to UniProtKB:  Q53HP3
Small Molecules
Ligands 5 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
MN
Query on MN

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Download CCD File 
A
MANGANESE (II) ION
Mn
WAEMQWOKJMHJLA-UHFFFAOYSA-N
 Ligand Interaction
MLI
Query on MLI

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Download CCD File 
A
MALONATE ION
C3 H2 O4
OFOBLEOULBTSOW-UHFFFAOYSA-L
 Ligand Interaction
FUC
Query on FUC

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Download CCD File 
A
ALPHA-L-FUCOSE
C6 H12 O5
SHZGCJCMOBCMKK-SXUWKVJYSA-N
 Ligand Interaction
BMA
Query on BMA

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Download CCD File 
A
BETA-D-MANNOSE
C6 H12 O6
WQZGKKKJIJFFOK-RWOPYEJCSA-N
 Ligand Interaction
NAG
Query on NAG

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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: 2.1 Å
  • R-Value Free: 0.240 
  • R-Value Work: 0.189 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 51.482α = 90.00
b = 77.185β = 109.55
c = 70.858γ = 90.00
Software Package:
Software NamePurpose
MOSFLMdata reduction
PDB_EXTRACTdata extraction
CCP4data scaling
PHASERphasing
REFMACrefinement
SCALAdata scaling
DNAdata collection

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2006-10-17
    Type: Initial release
  • Version 1.1: 2008-05-01
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Advisory, Version format compliance