7B2A image
Entry Detail
PDB ID:
7B2A
Title:
Complement inhibitor CirpA5 from Rhipicephalus appendiculatus
Biological Source:
Host Organism:
PDB Version:
Deposition Date:
2020-11-26
Release Date:
2021-12-08
Method Details:
Experimental Method:
Resolution:
1.91 Å
R-Value Free:
0.24
R-Value Work:
0.21
R-Value Observed:
0.22
Space Group:
I 2 2 2
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:CirpA5
Chain IDs:A
Chain Length:167
Number of Molecules:1
Biological Source:Rhipicephalus appendiculatus
Ligand Molecules
Primary Citation
Structure and function of a family of tick-derived complement inhibitors targeting properdin.
Nat Commun 13 317 317 (2022)
PMID: 35031611 DOI: 10.1038/s41467-021-27920-2

Abstact

Activation of the serum-resident complement system begins a cascade that leads to activation of membrane-resident complement receptors on immune cells, thus coordinating serum and cellular immune responses. Whilst many molecules act to control inappropriate activation, Properdin is the only known positive regulator of the human complement system. By stabilising the alternative pathway C3 convertase it promotes complement self-amplification and persistent activation boosting the magnitude of the serum complement response by all triggers. In this work, we identify a family of tick-derived alternative pathway complement inhibitors, hereafter termed CirpA. Functional and structural characterisation reveals that members of the CirpA family directly bind to properdin, inhibiting its ability to promote complement activation, and leading to potent inhibition of the complement response in a species specific manner. We provide a full functional and structural characterisation of a properdin inhibitor, opening avenues for future therapeutic approaches.

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Primary Citation of related structures