Structure of vaccinia complement protein in complex with heparin and potential implications for complement regulation
Abstract
Vaccinia virus complement control protein (VCP), a homolog of the regulators of the complement activation family of proteins, inhibits complement activation through mechanisms similar to human fluid-phase complement regulators factor H and C4b-binding protein. VCP has a heparin-binding activity that assists vaccinia in host interactions. Interaction with cell-surface polyanions like heparin is centrally important in the functioning of fluid-phase complement regulators and is the basis of host-target discrimination by the alternative pathway. We report the structure of VCP in complex with a heparin decasaccharide, which reveals changes in VCP that might be pertinent to complement regulation. Properties that VCP shares with fluid-phase complement regulators suggest that such conformational changes may be of relevance in the functioning of other complement regulators. Additionally, comparison of VCP-heparin interactions with potentially similar interactions in factor H might enable understanding of the structural basis of familial hemolytic uremic syndrome, attributed to mutational disruption of heparin and C3b binding by factor H.
- Publication:
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Proceedings of the National Academy of Science
- Pub Date:
- June 2004
- DOI:
- 10.1073/pnas.0400744101
- Bibcode:
- 2004PNAS..101.8924G
- Keywords:
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- BIOPHYSICS