The Interaction of Glycoprotein C of Herpes Simplex Virus Types 1 and 2 with the Alternative Complement Pathway
| Autor: | Gary H. Cohen, Charline Peng, Shan Ling Hung, Ioanna Kostavasili, Harvey M. Friedman, Roselyn J. Eisenberg, John D. Lambris |
|---|---|
| Rok vydání: | 1994 |
| Předmět: |
Blotting
Western Complement Pathway Alternative Mutant Enzyme-Linked Immunosorbent Assay chemical and pharmacologic phenomena Biology medicine.disease_cause Viral Envelope Proteins Neutralization Tests Virology medicine Animals Vero Cells chemistry.chemical_classification Mutation Properdin Complement C3 Recombinant Proteins C3-convertase Complement system Amino acid Biochemistry chemistry Receptors Complement 3b Alternative complement pathway Glycoprotein |
| Zdroj: | Virology. 203:299-312 |
| ISSN: | 0042-6822 |
| Popis: | Glycoprotein C (gC) of herpes simplex virus type 1 (HSV-1) or type 2 (HSV-2) binds the human complement fragment C3b, but the two proteins differ in their ability to bind C3b on infected cell surfaces. In addition, gC-1, but not gC-2, accelerates the decay of the alternative pathway C3 convertase, thereby affecting later steps of the complement cascade. Previously, we constructed linker insertion and deletion mutants of gC-1 and gC-2 and used transient transfection to express mutant proteins in uninfected cells. In spite of the differences between gC-1 and gC-2, C3b binding was localized to residues within the central portion of both proteins, encompassing the first four cysteines. For gC-1, deletion mutants lacking amino acids 33 to 123 or 367 to 469 or lacking both regions still bound C3b. We recombined these deleted forms of gC-1 into gC-39, an HSV-1 strain lacking the gC gene. The altered forms of gC-1 were incorporated into virions, expressed on the surface of infected cells, and bound C3b. We used these proteins to investigate the structural basis for the inhibitory action of gC-1 on the complement cascade. We found that gC-1 does not inhibit formation of the alternative pathway C3 convertase. This convertase is stabilized by the serum protein properdin. Purified gC-1, but not gC-2, inhibits the binding of properdin to C3b, suggesting that this destabilizes the convertase. The mutant lacking amino acids 367 to 449 was able to inhibit properdin binding to a limited extent when present at high concentrations, although it bound to C3b more weakly than wild-type gC. In contrast, the protein lacking amino acids 33 to 123 was unable to inhibit properdin binding to C3b. Thus, gC-1 contains two structural domains, one for C3b binding, residues 124 to 366, and another, residues 33 to 133, which interferes with properdin binding to C3b. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|