title: Rapid IgG heavy chain cleavage by the streptococcal IgG endopeptidase IdeS is mediated by IdeS monomers and is not due to enzyme dimerization.
abstract: Streptococcus pyogenes employs an IgG specific endopeptidase, IdeS, to counteract the effector functions of specific IgG. The physiological significant step in disarming specific IgG is the cleavage of one IgG heavy chain. So far, characterizations of IdeS enzymatic activity have employed techniques that failed to differentiate between the first and the second cleavage step. The present data demonstrate that IdeS is active as a monomer and that IdeS activity follows classical Michaelis-Menten kinetics arguing against the previously proposed formation of a functional IdeS dimer. Our results show that IdeS inactivates IgG 100-fold faster than previously reported.
authors.affiliation: Department of Molecular Biology and Umeå Centre for Microbial Research, Umeå University, 90187 Umeå, Sweden.
authors.forename: Reine
authors.initials: R
authors.lastname: Vindebro
authors.forename: Christian
authors.initials: C
authors.lastname: Spoerry
authors.forename: Ulrich
authors.initials: U
authors.lastname: von Pawel-Rammingen
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D007074:Immunoglobulin G / Q000378:metabolism*; D007143:Immunoglobulin Heavy Chains / Q000378:metabolism*; D007700:Kinetics; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D059748:Proteolysis
chemical_list: D001426:Bacterial Proteins; D007074:Immunoglobulin G; D007143:Immunoglobulin Heavy Chains; C442815:Mac-1-like protein, Streptococcus