6RQJ

Structure of human complement C5 complexed with tick inhibitors OmCI, RaCI1 and CirpT1


Experimental Data Snapshot

  • Method: ELECTRON MICROSCOPY
  • Resolution: 3.50 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 

wwPDB Validation 3D Report Full Report



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 U S A 117: 362-370

  • DOI: 10.1073/pnas.1909973116
  • Structures With Same Primary Citation

  • PubMed Abstract: 
  • 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 ...

    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

    Central Oxford Structural Molecular Imaging Centre, University of Oxford, OX1 3RE Oxford, United Kingdom.



Macromolecules

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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Complement C5A999Homo sapiensMutation(s): 0 
Gene Names: C5CPAMD4
Find proteins for P01031 (Homo sapiens)
Explore P01031 
Go to UniProtKB:  P01031
NIH Common Fund Data Resources
PHAROS  P01031
Protein Feature View
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  • Reference Sequence

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Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Complement inhibitorC165Rhipicephalus pulchellusMutation(s): 2 
Find proteins for Q5YD59 (Ornithodoros moubata)
Explore Q5YD59 
Go to UniProtKB:  Q5YD59
Protein Feature View
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  • Reference Sequence

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Entity ID: 3
MoleculeChainsSequence LengthOrganismDetails
Rhipicephalus appendiculatus RaCI1D81Rhipicephalus pulchellusMutation(s): 0 
Find proteins for A0A141SFN4 (Rhipicephalus appendiculatus)
Explore A0A141SFN4 
Go to UniProtKB:  A0A141SFN4
Protein Feature View
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  • Reference Sequence

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Entity ID: 4
MoleculeChainsSequence LengthOrganismDetails
Complement C5B655Homo sapiensMutation(s): 0 
Gene Names: C5CPAMD4
Find proteins for P01031 (Homo sapiens)
Explore P01031 
Go to UniProtKB:  P01031
NIH Common Fund Data Resources
PHAROS  P01031
Protein Feature View
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  • Reference Sequence

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Entity ID: 5
MoleculeChainsSequence LengthOrganismDetails
Putative 8.9 kDa family memberE112Rhipicephalus pulchellusMutation(s): 0 
Find proteins for L7MB58 (Rhipicephalus pulchellus)
Explore L7MB58 
Go to UniProtKB:  L7MB58
Protein Feature View
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  • Reference Sequence
Oligosaccharides
Entity ID: 6
MoleculeChainsChain Length2D Diagram Glycosylation
2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose
F
2 N-Glycosylation
Experimental Data & Validation

Experimental Data

  • Method: ELECTRON MICROSCOPY
  • Resolution: 3.50 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 

Structure Validation

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Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Finnish Cultural FoundationFinland--
Wellcome TrustUnited Kingdom100298
Wellcome TrustUnited Kingdom201536
Wolfson FoundationUnited KingdomWL160052

Revision History 

  • Version 1.0: 2020-01-08
    Type: Initial release
  • Version 1.1: 2020-01-15
    Changes: Source and taxonomy
  • Version 1.2: 2020-01-22
    Changes: Database references
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Advisory, Atomic model, Data collection, Derived calculations, Structure summary