Identification of the high affinity binding site in the Streptococcus intermedius toxin intermedilysin for its membrane receptor, the human complement regulator CD59.

ABSTRACT: The unique species specificity of the bacterial cytolysin intermedilysin is explained by its requirement for the human complement regulator CD59 as the primary receptor. Binding studies using individual domains of intermedilysin mapped the CD59-binding site to domain 4 and swap mutants between human and rabbit (non-intermedilysin-binding) CD59 implicated a short sequence (residues 42-59) in human CD59 in binding intermedilysin. We set out to map more closely the CD59 binding site in intermedilysin. We first looked for regions of homology between domain 4 in intermedilysin and the terminal complement components that bind CD59, C8 and C9. A nine amino acid sequence immediately adjacent the undecapeptide segment in intermedilysin domain 4 matched (5 of 9 identical, 3 of 9 conserved) a sequenc

SUBMITTER: Hughes TR 

PROVIDER: S-EPMC2697320 | biostudies-literature | 2009 Apr

REPOSITORIES: biostudies-literature