1cdr
STRUCTURE OF A SOLUBLE, GLYCOSYLATED FORM OF THE HUMAN COMPLEMENT REGULATORY PROTEIN CD59STRUCTURE OF A SOLUBLE, GLYCOSYLATED FORM OF THE HUMAN COMPLEMENT REGULATORY PROTEIN CD59
Structural highlights
DiseaseCD59_HUMAN Defects in CD59 are the cause of CD59 deficiency (CD59D) [MIM:612300.[1] FunctionCD59_HUMAN Potent inhibitor of the complement membrane attack complex (MAC) action. Acts by binding to the C8 and/or C9 complements of the assembling MAC, thereby preventing incorporation of the multiple copies of C9 required for complete formation of the osmolytic pore. This inhibitor appears to be species-specific. Involved in signal transduction for T-cell activation complexed to a protein tyrosine kinase. The soluble form from urine retains its specific complement binding activity, but exhibits greatly reduced ability to inhibit MAC assembly on cell membranes. 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 PubMedBACKGROUND: CD59 is a cell-surface glycoprotein that protects host cells from complement-mediated lysis by binding to and preventing the normal functioning of the complement proteins C8 and/or C9 which form part of a membrane penetrating assembly called the membrane attack complex. CD59 has no structural similarity to other complement proteins, but is an example of a plasma protein domain type found also in murine Ly-6 proteins and the urokinase-type plasminogen activator receptor. RESULTS: CD59 was purified from human urine, retaining the N-glycan and at least some of the non-lipid component of the glycosylphosphatidylinositol membrane anchor. The three-dimensional structure of the protein component has been determined in the presence of the carbohydrate groups using two-dimensional NMR spectroscopy. The protein structure is well defined by the NMR data (root mean square deviation from the mean structure of 0.65 A for backbone atoms and no distance constraint violations greater than 0.4 A). Structure calculations were also carried out to model the orientation of the N-acetylglucosamine residue that is directly linked to Asn18. CONCLUSIONS: The main features of the protein structure are two antiparallel beta-sheets (a central one with three strands and another with two), a short helix that packs against the three-stranded beta-sheet, and a carboxy-terminal region that, although lacking regular secondary structure, is well defined and packs against the three-stranded beta-sheet, on the opposite face to the helix. We have used the structure, in combination with existing biochemical data, to identify residues that may be involved in C8 binding. Structure of a soluble, glycosylated form of the human complement regulatory protein CD59.,Fletcher CM, Harrison RA, Lachmann PJ, Neuhaus D Structure. 1994 Mar 15;2(3):185-99. PMID:7520819[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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