5HCE image
Entry Detail
PDB ID:
5HCE
Keywords:
Title:
Ternary complex of human Complement C5 with Ornithodoros moubata OmCI and Rhipicephalus appendiculatus RaCI1
Biological Source:
PDB Version:
Deposition Date:
2016-01-04
Release Date:
2016-03-30
Method Details:
Experimental Method:
Resolution:
3.12 Å
R-Value Free:
0.28
R-Value Work:
0.26
R-Value Observed:
0.26
Space Group:
P 21 21 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Complement C5
Chain IDs:B (auth: A)
Chain Length:998
Number of Molecules:1
Biological Source:Homo sapiens
Polymer Type:polypeptide(L)
Description:Complement C5
Chain IDs:A (auth: B)
Chain Length:656
Number of Molecules:1
Biological Source:Homo sapiens
Polymer Type:polypeptide(L)
Description:Complement inhibitor
Mutations:N78Q, N102Q
Chain IDs:C
Chain Length:165
Number of Molecules:1
Biological Source:Ornithodoros moubata
Polymer Type:polypeptide(L)
Description:Rhipicephalus appendiculatus RaCI1
Chain IDs:D
Chain Length:81
Number of Molecules:1
Biological Source:Rhipicephalus appendiculatus
Ligand Molecules
Primary Citation
Structural basis for therapeutic inhibition of complement C5.
Nat.Struct.Mol.Biol. 23 378 386 (2016)
PMID: 27018802 DOI: 10.1038/nsmb.3196

Abstact

Activation of complement C5 generates the potent anaphylatoxin C5a and leads to pathogen lysis, inflammation and cell damage. The therapeutic potential of C5 inhibition has been demonstrated by eculizumab, one of the world's most expensive drugs. However, the mechanism of C5 activation by C5 convertases remains elusive, thus limiting development of therapeutics. Here we identify and characterize a new protein family of tick-derived C5 inhibitors. Structures of C5 in complex with the new inhibitors, the phase I and phase II inhibitor OmCI, or an eculizumab Fab reveal three distinct binding sites on C5 that all prevent activation of C5. The positions of the inhibitor-binding sites and the ability of all three C5-inhibitor complexes to competitively inhibit the C5 convertase conflict with earlier steric-inhibition models, thus suggesting that a priming event is needed for activation.

Legend

Protein

Chemical

Disease

Primary Citation of related structures