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
The crystal structure of profactor D, determined at 2.1 A resolution with an Rfree and an R-factor of 25.1 and 20.4%, respectively, displays highly flexible or disordered conformation for five regions: N-22, 71-76, 143-152, 187-193 and 215-223. A comparison with the structure of its mature serine protease, complement factor D, revealed major conformational changes in the similar regions. Comparisons with the zymogen-active enzyme pairs of chymotrypsinogen, trypsinogen and prethrombin-2 showed a similar distribution of the flexible regions. However, profactor D is the most flexible of the four, and its mature enzyme displays inactive, self-inhibited active site conformation. Examination of the surface properties of the N-terminus-binding pocket indicates that Ile16 may play the initial positioning role for the N-terminus, and Leu17 probably also helps in inducing the required conformational changes. This process, perhaps shared by most chymotrypsinogen-like zymogens, is followed by a factor D-unique step, the re-orientation of an external Arg218 to an internal position for salt-bridging with Asp189, leading to the generation of the self-inhibited factor D.
Structural basis of profactor D activation: from a highly flexible zymogen to a novel self-inhibited serine protease, complement factor D.,Jing H, Macon KJ, Moore D, DeLucas LJ, Volanakis JE, Narayana SV EMBO J. 1999 Feb 15;18(4):804-14. PMID:10022823[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Jing H, Macon KJ, Moore D, DeLucas LJ, Volanakis JE, Narayana SV. Structural basis of profactor D activation: from a highly flexible zymogen to a novel self-inhibited serine protease, complement factor D. EMBO J. 1999 Feb 15;18(4):804-14. PMID:10022823 doi:10.1093/emboj/18.4.804
