6RPT

Structure of tick complement inhibitor CirpT1 complexed with macroglobubulin domain 4 of human complement C5


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.7 Å
  • R-Value Free: 0.272 
  • R-Value Work: 0.226 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

An inhibitor of complement C5 provides structural insights into activation.

Reichhardt, M.P.Johnson, S.Tang, T.Morgan, T.Tebeka, N.Popitsch, N.Deme, J.C.Jore, M.M.Lea, S.M.

(2020) Proc.Natl.Acad.Sci.USA 117: 362-370

  • DOI: 10.1073/pnas.1909973116
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • The complement system is a crucial part of innate immune defenses against invading pathogens. The blood-meal of the tick <i>Rhipicephalus pulchellus </i> lasts for days, and the tick must therefore rely on inhibitors to counter complement activation ...

    The complement system is a crucial part of innate immune defenses against invading pathogens. The blood-meal of the tick Rhipicephalus pulchellus lasts for days, and the tick must therefore rely on inhibitors to counter complement activation. We have identified a class of inhibitors from tick saliva, the CirpT family, and generated detailed structural data revealing their mechanism of action. We show direct binding of a CirpT to complement C5 and have determined the structure of the C5-CirpT complex by cryoelectron microscopy. This reveals an interaction with the peripheral macro globulin domain 4 (C5_MG4) of C5. To achieve higher resolution detail, the structure of the C5_MG4-CirpT complex was solved by X-ray crystallography (at 2.7 Å). We thus present the fold of the CirpT protein family, and provide detailed mechanistic insights into its inhibitory function. Analysis of the binding interface reveals a mechanism of C5 inhibition, and provides information to expand our biological understanding of the activation of C5, and thus the terminal complement pathway.


    Organizational Affiliation

    Sir William Dunn School of Pathology, University of Oxford, OX1 3RE Oxford, United Kingdom; susan.lea@path.ox.ac.uk.,Wellcome Centre for Human Genetics, University of Oxford, OX3 7BN Oxford, United Kingdom.,Sir William Dunn School of Pathology, University of Oxford, OX1 3RE Oxford, United Kingdom.,Central Oxford Structural Molecular Imaging Centre, University of Oxford, OX1 3RE Oxford, United Kingdom.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Complement C5
E, A, C
133Homo sapiensMutation(s): 0 
Gene Names: C5 (CPAMD4)
Find proteins for P01031 (Homo sapiens)
Go to Gene View: C5
Go to UniProtKB:  P01031
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Putative 8.9 kDa family member
F, B, D
113Rhipicephalus pulchellusMutation(s): 0 
Find proteins for L7MB58 (Rhipicephalus pulchellus)
Go to UniProtKB:  L7MB58
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
GOL
Query on GOL

Download SDF File 
Download CCD File 
A, B, C, E, F
GLYCEROL
GLYCERIN; PROPANE-1,2,3-TRIOL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.7 Å
  • R-Value Free: 0.272 
  • R-Value Work: 0.226 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 86.830α = 90.00
b = 56.948β = 113.02
c = 90.072γ = 90.00
Software Package:
Software NamePurpose
DIALSdata scaling
DIALSdata reduction
MOLREPphasing
PHENIXrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Finnish Cultural FoundationFinland--
Wellcome TrustUnited Kingdom100298

Revision History 

  • Version 1.0: 2020-01-08
    Type: Initial release
  • Version 1.1: 2020-01-15
    Type: Database references