5HKJ

Single Chain Recombinant Globular Head of the Complement System Protein C1q


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.35 Å
  • R-Value Free: 0.200 
  • R-Value Work: 0.175 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structural and Functional Characterization of a Single-Chain Form of the Recognition Domain of Complement Protein C1q.

Moreau, C.Bally, I.Chouquet, A.Bottazzi, B.Ghebrehiwet, B.Gaboriaud, C.Thielens, N.

(2016) Front Immunol 7: 79-79

  • DOI: 10.3389/fimmu.2016.00079
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Complement C1q is a soluble pattern recognition molecule comprising six heterotrimeric subunits assembled from three polypeptide chains (A-C). Each heterotrimer forms a collagen-like stem prolonged by a globular recognition domain. These recognition ...

    Complement C1q is a soluble pattern recognition molecule comprising six heterotrimeric subunits assembled from three polypeptide chains (A-C). Each heterotrimer forms a collagen-like stem prolonged by a globular recognition domain. These recognition domains sense a wide variety of ligands, including pathogens and altered-self components. Ligand recognition is either direct or mediated by immunoglobulins or pentraxins. Multivalent binding of C1q to its targets triggers immune effector mechanisms mediated via its collagen-like stems. The induced immune response includes activation of the classical complement pathway and enhancement of the phagocytosis of the recognized target. We report here, the first production of a single-chain recombinant form of human C1q globular region (C1q-scGR). The three monomers have been linked in tandem to generate a single continuous polypeptide, based on a strategy previously used for adiponectin, a protein structurally related to C1q. The resulting C1q-scGR protein was produced at high yield in stably transfected 293-F mammalian cells. Recombinant C1q-scGR was correctly folded, as demonstrated by its X-ray crystal structure solved at a resolution of 1.35 Å. Its interaction properties were assessed by surface plasmon resonance analysis using the following physiological C1q ligands: the receptor for C1q globular heads, the long pentraxin PTX3, calreticulin, and heparin. The 3D structure and the binding properties of C1q-scGR were similar to those of the three-chain fragment generated by collagenase digestion of serum-derived C1q. Comparison of the interaction properties of the fragments with those of native C1q provided insights into the avidity component associated with the hexameric assembly of C1q. The interest of this functional recombinant form of the recognition domains of C1q in basic research and its potential biomedical applications are discussed.


    Organizational Affiliation

    IBS, University of Grenoble Alpes, Grenoble, France; CNRS, IBS, Grenoble, France; IBS, CEA, Grenoble, France.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Complement C1q subcomponent subunit A,Complement C1q subcomponent subunit C,Complement C1q subcomponent subunit B
A
410Homo sapiensMutation(s): 0 
Gene Names: C1QB, C1QC (C1QG), C1QA
Find proteins for P02746 (Homo sapiens)
Go to Gene View: C1QB
Go to UniProtKB:  P02746
Find proteins for P02747 (Homo sapiens)
Go to Gene View: C1QC
Go to UniProtKB:  P02747
Find proteins for P02745 (Homo sapiens)
Go to Gene View: C1QA
Go to UniProtKB:  P02745
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CA
Query on CA

Download SDF File 
Download CCD File 
A
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-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: 1.35 Å
  • R-Value Free: 0.200 
  • R-Value Work: 0.175 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 81.115α = 90.00
b = 52.729β = 115.22
c = 89.930γ = 90.00
Software Package:
Software NamePurpose
Cootmodel building
PHENIXrefinement
XDSdata reduction
PHASERphasing
XSCALEdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
French National Research AgencyFranceANR 09-PIRI-0021

Revision History 

  • Version 1.0: 2016-03-02
    Type: Initial release
  • Version 1.1: 2016-03-30
    Type: Database references
  • Version 1.2: 2017-08-30
    Type: Advisory, Author supporting evidence