Activating Compound | Comment | Organism | Structure |
---|---|---|---|
complement factor B | the enzyme factor D is activated by its substrate factor B through interactions outside the active site. The substrate-binding, or exosite, region displays a well defined and rigid conformation | Homo sapiens |
Cloned (Comment) | Organism |
---|---|
transient expression of wild-type and mutant enzymes in HEK-293-E cells from pUPE.05.05 expression vectors, the recombinant proteins are secreted | Homo sapiens |
Crystallization (Comment) | Organism |
---|---|
wild-type enzyme, mutants R202A and S81Y/T198S/S199W, and enzyme mutant S183A in ternary complex with C3bB, hanging drop vapour diffusion technique, mixing of 10 mg/ml protein solution with reservoir solution consisting of 15% w/v PEG 6000, 50 mM MES-NaOH pH 6.0, 18°C, 6 days, X-ray diffraction structure determination and analysis at 1.8 A, 2.8 A, 2.0 A, and 3.5 A resolution, respectively, molecular replacement and ensemble refinement | Homo sapiens |
Protein Variants | Comment | Organism |
---|---|---|
R202A | site-directed mutagenesis, the mutation R202A removes the Arg202-Asp177 salt bridge, the mutant variant has enhanced activity towards artificial peptides compared to the wild-type enzyme and simultaneously displays active and inactive conformations of the active site. Ensemble refinement reveals pronounced disorder in the exosite loops for this enzyme variant, reminiscent of thrombin in the absence of the stabilizing Na+ ion, structure analysis | Homo sapiens |
S183A | site-directed mutagenesis, structure analysis | Homo sapiens |
S81Y/T198S/S199W | site-directed mutagenesis, the mutation causes steric hindrance of Trp199 resulting in pronounced rearrangement of the proteinase active-site region, structure analysis | Homo sapiens |
Inhibitors | Comment | Organism | Structure |
---|---|---|---|
additional information | human factor D is a self-inhibited thrombin-like serine proteinase. Ser199 of the self-inhibitory loop blocks the formation of the canonical active configurations | Homo sapiens |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
complement component C3bB + H2O | Homo sapiens | - |
? | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Homo sapiens | P00746 | - |
- |
Purification (Comment) | Organism |
---|---|
recombinant soluble wild-type and mutant enzymes from HEK-293-E cells by cation exchange chromatography and gel filtration | Homo sapiens |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
complement component C3bB + H2O | - |
Homo sapiens | ? | - |
? |
Synonyms | Comment | Organism |
---|---|---|
factor D | - |
Homo sapiens |
General Information | Comment | Organism |
---|---|---|
additional information | the substrate-binding, or exosite, region displays a well defined and rigid conformation. A salt bridge between Arg202 on the self-inhibitory loop and Asp177 locks the S1 pocket and rigidifies the exosite. Asp-His-Ser catalytic site. The enzyme exhibits conformational dynamics like thrombin, but unlike in thrombin a mechanism has evolved in factor D that locks the unbound native state into an ordered inactive conformation via the self-inhibitory loop. The Asp-His-Ser catalytic site of the enzyme is in an enzymatically active conformation induced by substrate binding at the exosite | Homo sapiens |
physiological function | human factor D is a self-inhibited thrombin-like serine proteinase that is critical for amplification of the complement immune response | Homo sapiens |