This model represents the N-terminal half of a family of Streptococcal proteins that contain a signal peptide and then up to five repeats of a region that includes a His-X-X-His-X-His (histidine triad) motif. Three repeats are found in the seed alignment. Additional copies in more poorly conserved regions may be detected. Members of this family from Streptococcus pneumoniae are suggested to cleave human C3, and the member PhpA has been shown in vaccine studies to be a protective antigen in mice. [Cellular processes, Pathogenesis]