title: EndoS2 is a unique and conserved enzyme of serotype M49 group A Streptococcus that hydrolyses N-linked glycans on IgG and α1-acid glycoprotein.
abstract: Many bacteria have evolved ways to interact with glycosylation functions of the immune system of their hosts. Streptococcus pyogenes [GAS (group A Streptococcus)] secretes the enzyme EndoS that cleaves glycans on human IgG and impairs the effector functions of the antibody. The ndoS gene, encoding EndoS, has, until now, been thought to be conserved throughout the serotypes. However, in the present study, we identify EndoS2, an endoglycosidase in serotype M49 GAS strains. We characterized EndoS2 and the corresponding ndoS2 gene using sequencing, bioinformatics, phylogenetic analysis, recombinant expression and LC-MS analysis of glycosidic activity. This revealed that EndoS2 is present exclusively, and highly conserved, in serotype M49 of GAS and is only 37% identical with EndoS. EndoS2 showed endo-β-N-acetylglucosaminidase activity on all N-linked glycans of IgG and on biantennary and sialylated glycans of AGP (α1-acid glycoprotein). The enzyme was found to act only on native IgG and AGP and to be specific for free biantennary glycans with or without terminal sialylation. GAS M49 expression of EndoS2 was monitored in relation to carbohydrates present in the culture medium and was linked to the presence of sucrose. We conclude that EndoS2 is a unique endoglycosidase in serotype M49 and differs from EndoS of other GAS strains by targeting both IgG and AGP. EndoS2 expands the repertoire of GAS effectors that modify key glycosylated molecules of host defence.
authors.affiliation: *Department of Clinical Sciences, Division of Infection Medicine, Lund University, Biomedical Center B14, SE-22184 Lund, Sweden.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Sjögren
authors.forename: Weston B
authors.initials: WB
authors.lastname: Struwe
authors.forename: Eoin F J
authors.initials: EF
authors.lastname: Cosgrave
authors.forename: Pauline M
authors.initials: PM
authors.lastname: Rudd
authors.forename: Martin
authors.initials: M
authors.lastname: Stervander
authors.forename: Maria
authors.initials: M
authors.lastname: Allhorn
authors.forename: Andrew
authors.initials: A
authors.lastname: Hollands
authors.forename: Victor
authors.initials: V
authors.lastname: Nizet
authors.forename: Mattias
authors.initials: M
authors.lastname: Collin
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002240:Carbohydrate Sequence; D017124:Conserved Sequence; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D054884:Host-Pathogen Interactions; D006801:Humans; D007074:Immunoglobulin G / Q000737:chemistry / Q000378:metabolism*; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009961:Orosomucoid / Q000737:chemistry / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013297:Streptococcus pyogenes / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D013379:Substrate Specificity; D013395:Sucrose / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D007074:Immunoglobulin G; D007527:Isoenzymes; D009961:Orosomucoid; D011994:Recombinant Proteins; D013395:Sucrose; D006026:Glycoside Hydrolases; C431325:NDOS protein, Streptococcus pyogenes