4LOR

C1s CUB1-EGF-CUB2 in complex with a collagen-like peptide from C1q


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.5 Å
  • R-Value Free: 0.252 
  • R-Value Work: 0.196 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structural basis of the C1q/C1s interaction and its central role in assembly of the C1 complex of complement activation.

Venkatraman Girija, U.Gingras, A.R.Marshall, J.E.Panchal, R.Sheikh, M.A.Gal, P.Schwaeble, W.J.Mitchell, D.A.Moody, P.C.Wallis, R.

(2013) Proc.Natl.Acad.Sci.USA 110: 13916-13920

  • DOI: 10.1073/pnas.1311113110
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Complement component C1, the complex that initiates the classical pathway of complement activation, is a 790-kDa assembly formed from the target-recognition subcomponent C1q and the modular proteases C1r and C1s. The proteases are elongated tetramers ...

    Complement component C1, the complex that initiates the classical pathway of complement activation, is a 790-kDa assembly formed from the target-recognition subcomponent C1q and the modular proteases C1r and C1s. The proteases are elongated tetramers that become more compact when they bind to the collagen-like domains of C1q. Here, we describe a series of structures that reveal how the subcomponents associate to form C1. A complex between C1s and a collagen-like peptide containing the C1r/C1s-binding motif of C1q shows that the collagen binds to a shallow groove via a critical lysine side chain that contacts Ca(2+)-coordinating residues. The data explain the Ca(2+)-dependent binding mechanism, which is conserved in C1r and also in mannan-binding lectin-associated serine proteases, the serine proteases of the lectin pathway activation complexes. In an accompanying structure, C1s forms a compact ring-shaped tetramer featuring a unique head-to-tail interaction at its center that replicates the likely arrangement of C1r/C1s polypeptides in the C1 complex. Additional structures reveal how C1s polypeptides are positioned to enable activation by C1r and interaction with the substrate C4 inside the cage-like assembly formed by the collagenous stems of C1q. Together with previously determined structures of C1r fragments, the results reported here provide a structural basis for understanding the early steps of complement activation via the classical pathway.


    Organizational Affiliation

    Department of Infection, University of Leicester, Leicester LE1 9HN, United Kingdom.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Complement C1s subcomponent heavy chain
A
276Homo sapiensMutation(s): 0 
Gene Names: C1S
EC: 3.4.21.42
Find proteins for P09871 (Homo sapiens)
Go to Gene View: C1S
Go to UniProtKB:  P09871
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
collagen-like peptide from C1q
B, C, D
29N/AMutation(s): 0 
Protein Feature View is not available: No corresponding UniProt sequence found.
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NA
Query on NA

Download SDF File 
Download CCD File 
A
SODIUM ION
Na
FKNQFGJONOIPTF-UHFFFAOYSA-N
 Ligand Interaction
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
Modified Residues  3 Unique
IDChainsTypeFormula2D DiagramParent
NH2
Query on NH2
B, C, D
NON-POLYMERH2 N

--

HYP
Query on HYP
B, C, D
L-PEPTIDE LINKINGC5 H9 N O3PRO
ACE
Query on ACE
B, C, D
NON-POLYMERC2 H4 O

--

Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.5 Å
  • R-Value Free: 0.252 
  • R-Value Work: 0.196 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 71.353α = 90.00
b = 71.173β = 111.12
c = 98.393γ = 90.00
Software Package:
Software NamePurpose
MOSFLMdata reduction
PHENIXrefinement
PDB_EXTRACTdata extraction
SCALAdata scaling
PHASERphasing
StructureStudiodata collection

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2013-08-07
    Type: Initial release
  • Version 1.1: 2013-08-28
    Type: Database references
  • Version 1.2: 2013-09-04
    Type: Database references