2CM4

The complement inhibitor OmCI in complex with ricinoleic acid


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Work: 0.169 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

The Structure of Omci, a Novel Lipocalin Inhibitor of the Complement System.

Roversi, P.Lissina, O.Johnson, S.Ahmat, N.Paesen, G.C.Ploss, K.Boland, W.Nunn, M.A.Lea, S.M.

(2007) J.Mol.Biol. 369: 784

  • DOI: 10.1016/j.jmb.2007.03.064
  • Primary Citation of Related Structures:  
  • Also Cited By: 3ZUO, 3ZUI

  • PubMed Abstract: 
  • The complement (C) system is a potent innate immune defence system against parasites. We have recently characterised and expressed OmCI, a 16 kDa protein derived from the soft tick Ornithodoros moubata that specifically binds C5, thereby preventing C ...

    The complement (C) system is a potent innate immune defence system against parasites. We have recently characterised and expressed OmCI, a 16 kDa protein derived from the soft tick Ornithodoros moubata that specifically binds C5, thereby preventing C activation. The structure of recombinant OmCI determined at 1.9 A resolution confirms a lipocalin fold and reveals that the protein binds a fatty acid derivative that we have identified by mass spectrometry as ricinoleic acid. We propose that OmCI could sequester one of the fatty acid-derived inflammatory modulators from the host plasma, thereby interfering with the host inflammatory response to the tick bite. Mapping of sequence differences between OmCI and other tick lipocalins with different functions, combined with biochemical investigations of OmCI activity, supports the hypothesis that OmCI acts by preventing interaction with the C5 convertase, rather than by blocking the C5a cleavage site.


    Organizational Affiliation

    Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, England, UK.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
COMPLEMENT INHIBITOR
A
150Ornithodoros moubataMutation(s): 2 
Gene Names: CI
Find proteins for Q5YD59 (Ornithodoros moubata)
Go to UniProtKB:  Q5YD59
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ACT
Query on ACT

Download SDF File 
Download CCD File 
A
ACETATE ION
C2 H3 O2
QTBSBXVTEAMEQO-UHFFFAOYSA-M
 Ligand Interaction
RCL
Query on RCL

Download SDF File 
Download CCD File 
A
RICINOLEIC ACID
C18 H34 O3
WBHHMMIMDMUBKC-XLNAKTSKSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Work: 0.169 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 45.170α = 90.00
b = 55.520β = 90.00
c = 60.620γ = 90.00
Software Package:
Software NamePurpose
MOSFLMdata reduction
TNTrefinement
SCALAdata scaling
AMoREphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2007-05-01
    Type: Initial release
  • Version 1.1: 2011-05-08
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance