Identification of a major serum DNA-binding protein as factor B of the alternative complement pathway
| Autor: | W D Gardner, J A Haselby, S O Hoch |
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| Rok vydání: | 1980 |
| Předmět: | |
| Zdroj: | The Journal of Immunology. 124:2800-2806 |
| ISSN: | 1550-6606 0022-1767 |
| DOI: | 10.4049/jimmunol.124.6.2800 |
| Popis: | One of the major proteins in human serum capable of binding DNA has been shown to be factor B of the alternative pathway of complement activation. This protein, designated DNA-binding protein-2 (DBP-2), is recognized by antisera directed against both factor B and its activated form, fragment Bb. Its m.w., charge microheterogeneity, and amino acid composition correspond closely with reported values for those properties of factor B. A radioimmunoassay was used to estimate the serum concentration of DBP-2 at 266 +/- 83 microgram/ml, which also corresponds with the level of factor B normally present in the serum. DBP-2 functions as factor B in the activation of factor B-depleted serum. Limited proteolytic treatment of DBP-2 produced a fragment pattern resembling that of factor B both in the m.w. of the fragments and their electrophoretic mobilities. By means of DNA affinity chromatography of the fragments produced by trypsinization, the DNA-binding domain of DBP-2 was localized. |
| Databáze: | OpenAIRE |
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