<p>This entry represents a repeated sequence region that includes a His-X-X-His-X-His (histidine triad) motif, which is found in family of Streptococcal proteins. Members of the family are suggested to cleave human complement component 3, and family member PhpA has been shown in vaccine studies to be a protective antigen in mice [<cite idref="PUB00009544"/>]. </p>