title: Virulent human strains of group G streptococci express a C5a peptidase enzyme similar to that produced by group A streptococci.
abstract: Specific proteolytic destruction of the human chemotaxin, C5a, is a property of group A and B streptococcal pathogens. Here we show that virulent group G streptococci from human sources also express C5a peptidase activity. The enzyme responsible for this activity is approximately the same size as and is antigenically similar to that produced by group A streptococci. On the basis of Southern hybridization analysis with an internal fragment of the group A C5a peptidase gene (scpA) as a probe, a copy of this gene was found in the genome of all group G human isolates tested. Comparison of partial restriction maps of scpA and scpG revealed significant similarity between the two genes. Group G strains isolated from dogs and cows were found to lack C5a peptidase activity and did not hybridize to the scpA-specific probe. The association of this activity with three streptococcal species suggests that elimination of phagocyte chemotactic attractants is a more universal virulence mechanism than originally anticipated.
authors.affiliation: Department of Microbiology, University of Minnesota, Minneapolis 55455.
authors.forename: P P
authors.initials: PP
authors.lastname: Cleary
authors.forename: J
authors.initials: J
authors.lastname: Peterson
authors.forename: C
authors.initials: C
authors.lastname: Chen
authors.forename: C
authors.initials: C
authors.lastname: Nelson
mesh_terms: D018829:Adhesins, Bacterial; D000942:Antigens, Bacterial / Q000276:immunology; D015139:Blotting, Southern; D015153:Blotting, Western; D002634:Chemotaxis, Leukocyte; D003429:Cross Reactions; D004269:DNA, Bacterial / Q000235:genetics; D010450:Endopeptidases / Q000276:immunology / Q000378:metabolism*; D005798:Genes, Bacterial; D006801:Humans; D015183:Restriction Mapping; D013291:Streptococcus / Q000201:enzymology* / Q000235:genetics / Q000276:immunology / Q000472:pathogenicity
chemical_list: D018829:Adhesins, Bacterial; D000942:Antigens, Bacterial; D004269:DNA, Bacterial; D010450:Endopeptidases; C053088:C5a peptidase