4D9Q image
Deposition Date 2012-01-11
Release Date 2012-02-22
Last Version Date 2024-10-09
Entry Detail
PDB ID:
4D9Q
Title:
Inhibiting Alternative Pathway Complement Activation by Targeting the Exosite on Factor D
Biological Source:
Source Organism:
Macaca mulatta (Taxon ID: 9544)
Homo sapiens (Taxon ID: 9606)
Host Organism:
Method Details:
Experimental Method:
Resolution:
2.28 Å
R-Value Free:
0.23
R-Value Work:
0.18
R-Value Observed:
0.19
Space Group:
C 1 2 1
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:Factor D
Gene (Uniprot):CFD
Chain IDs:A, B
Chain Length:228
Number of Molecules:2
Biological Source:Macaca mulatta
Polymer Type:polypeptide(L)
Molecule:Anti-Factor D, light chain
Chain IDs:C (auth: D), F (auth: L)
Chain Length:213
Number of Molecules:2
Biological Source:Homo sapiens
Polymer Type:polypeptide(L)
Molecule:Anti-Factor D, heavy chain
Gene (Uniprot):IGHG1
Chain IDs:D (auth: E), E (auth: H)
Chain Length:217
Number of Molecules:2
Biological Source:Homo sapiens
Primary Citation
Inhibiting alternative pathway complement activation by targeting the factor d exosite.
J.Biol.Chem. 287 12886 12892 (2012)
PMID: 22362762 DOI: 10.1074/jbc.M112.345082

Abstact

By virtue of its amplifying property, the alternative complement pathway has been implicated in a number of inflammatory diseases and constitutes an attractive therapeutic target. An anti-factor D Fab fragment (AFD) was generated to inhibit the alternative complement pathway in advanced dry age-related macular degeneration. AFD potently prevented factor D (FD)-mediated proteolytic activation of its macromolecular substrate C3bB, but not proteolysis of a small synthetic substrate, indicating that AFD did not block access of the substrate to the catalytic site. The crystal structures of AFD in complex with human and cynomolgus FD (at 2.4 and 2.3 Å, respectively) revealed the molecular details of the inhibitory mechanism. The structures show that the AFD-binding site includes surface loops of FD that form part of the FD exosite. Thus, AFD inhibits FD proteolytic function by interfering with macromolecular substrate access rather than by inhibiting FD catalysis, providing the molecular basis of AFD-mediated inhibition of a rate-limiting step in the alternative complement pathway.

Legend

Protein

Chemical

Disease

Primary Citation of related structures