Species-specific differences in the structure of orthopoxvirus complement-binding protein

Vaccinia virus complement-binding protein (VCP) is secreted from the cells infected with the virus and controls the complement activation reactions. T his protein contains four short consensus repeats (SCR), typical of the pro tein family of complement activation regulators. Organization of the VCP ge nes/proteins of orthopoxviruses-monkey-pox (MPV), variola, cowpox and vacci nia viruses-and their cellular homologues (DAF and C4BP) were studied compa ratively, For this purpose, VCP genes of three MPV strains were sequenced. VCP gene sequences of other human-pathogenic orthopoxvirus species and stra ins determined earlier were involved in the analysis. It has been demonstra ted that a premature termination of the MPV VCP open reading frame results in a truncated protein sequence carrying a deletion of the C-terminal SCR4. This is an essential distinction of MPV from other orthopoxvirus species. (C) 2001 Elsevier Science B.V. All rights reserved.