Recombinant endopeptidases IdeS and IdeZ and their potential applications

IdeS and IdeZ endopeptidases are streptococcal virulence factors that specifically cleave IgG heavy chains and represent an interest from biotechnological, medical, and veterinary points of view. The genes encoding IdeS and IdeZ endopeptidases (the ideS gene was cloned from a Streptococcus pyogenes collection strain, and S. zooepidemicusideZ gene was synthesized) were cloned and expressed in Escherichia coli heterologous expression system, and 6His-tag affinity domain was introduced into the amino acid sequence of each endopeptidase. IdeS and IdeZ enzymes were isolated and purified by metal affinity chromatography. The resulting IdeS and IdeZ are apparently homogeneous on polyacrylamide gel electrophoresis and are active against human and animal IgG. The specificity of human IgG cleavage by endopeptidases IdeS and IdeZ was confirmed by polyacrylamide gel electrophoresis. Application of recombinant IdeZ was demonstrated for immunological analysis of equine “strangles” (diagnostics and specific antibodies’ titer determination in the blood). Thus, IdeZ can be used in veterinary medicine and sanitary microbiology for the diagnosis of infections caused by S. equi and S. zooepidemicus in addition to their applications in medicine and biotechnology.