Structural highlights
Disease
[CFAD_HUMAN] Defects in CFD are the cause of complement factor D deficiency (CFDD) [MIM:613912]. CFDD is an immunologic disorder characterized by increased susceptibility to bacterial infections, particularly Neisseria infections, due to a defect in the alternative complement pathway.
Function
[CFAD_HUMAN] Factor D cleaves factor B when the latter is complexed with factor C3b, activating the C3bbb complex, which then becomes the C3 convertase of the alternate pathway. Its function is homologous to that of C1s in the classical pathway.
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Complement factor D is a serine protease regulated by a novel mechanism that depends on conformational changes rather than cleavage of a zymogen for expression of proteolytic activity. The conformational changes are presumed to be induced by the single natural substrate, C3bB, and to result in reversible reorientation of the catalytic center and of the substrate binding site of factor D, both of which have atypical conformations. Here we report that replacement of Ser94, Thr214, and Ser215 of factor D (chymotrypsinogen numbering has been used for comparison purposes) with the corresponding residues of trypsin, Tyr, Ser, and Trp, is sufficient to induce substantially higher catalytic activity associated with a typical serine protease alignment of the catalytic triad residues His57, Asp102, and Ser195. These results provide a partial structural explanation for the low reactivity of "resting-state" factor D toward synthetic substrates.
Crystal structure of a complement factor D mutant expressing enhanced catalytic activity.,Kim S, Narayana SV, Volanakis JE J Biol Chem. 1995 Oct 13;270(41):24399-405. PMID:7592653[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Kim S, Narayana SV, Volanakis JE. Crystal structure of a complement factor D mutant expressing enhanced catalytic activity. J Biol Chem. 1995 Oct 13;270(41):24399-405. PMID:7592653
