scholarly journals Functional analysis of a group A streptococcal glycoside hydrolase Spy1600 from family 84 reveals it is a β-N-acetylglucosaminidase and not a hyaluronidase

2006 ◽  
Vol 399 (2) ◽  
pp. 241-247 ◽  
Author(s):  
William L. Sheldon ◽  
Matthew S. Macauley ◽  
Edward J. Taylor ◽  
Charlotte E. Robinson ◽  
Simon J. Charnock ◽  
...  
Keyword(s):  
Glycoside Hydrolase ◽  
Catalytic Mechanism ◽  
Group A Streptococcus ◽  
Competitive Inhibitor ◽  
Glycoside Hydrolases ◽  
Glycoside Hydrolase Family ◽  
Toxic Shock ◽  
Nmr Studies ◽  
Invasive Infections ◽  
Group A

Group A streptococcus (Streptococcus pyogenes) is the causative agent of severe invasive infections such as necrotizing fasciitis (the so-called ‘flesh eating disease’) and toxic-shock syndrome. Spy1600, a glycoside hydrolase from family 84 of the large superfamily of glycoside hydrolases, has been proposed to be a virulence factor. In the present study we show that Spy1600 has no activity toward galactosaminides or hyaluronan, but does remove β-O-linked N-acetylglucosamine from mammalian glycoproteins – an observation consistent with the inclusion of eukaryotic O-glycoprotein 2-acetamido-2-deoxy-β-D-glucopyranosidases within glycoside hydrolase family 84. Proton NMR studies, structure–reactivity studies for a series of fluorinated analogues and analysis of 1,2-dideoxy-2′-methyl-α-D-glucopyranoso-[2,1-d]-Δ2′-thiazoline as a competitive inhibitor reveals that Spy1600 uses a double-displacement mechanism involving substrate-assisted catalysis. Family 84 glycoside hydrolases are therefore comprised of both prokaryotic and eukaryotic β-N-acetylglucosaminidases using a conserved catalytic mechanism involving substrate-assisted catalysis. Since these enzymes do not have detectable hyaluronidase activity, many family 84 glycoside hydrolases are most likely incorrectly annotated as hyaluronidases.

scholarly journals Functional metagenomics identifies an exosialidase with an inverting catalytic mechanism that defines a new glycoside hydrolase family (GH156)

2018 ◽  
Vol 293 (47) ◽  
pp. 18138-18150 ◽  
Author(s):  
Léa Chuzel ◽  
Mehul B. Ganatra ◽  
Erdmann Rapp ◽  
Bernard Henrissat ◽  
Christopher H. Taron
Keyword(s):  
Glycoside Hydrolase ◽  
Catalytic Mechanism ◽  
Recombinant Expression ◽  
Biochemical Property ◽  
Environmental Dna ◽  
Thermal Spring ◽  
Sialic Acid Residue ◽  
Glycoside Hydrolases ◽  
Glycoside Hydrolase Family ◽  
Hydrolase Family

Exosialidases are glycoside hydrolases that remove a single terminal sialic acid residue from oligosaccharides. They are widely distributed in biology, having been found in prokaryotes, eukaryotes, and certain viruses. Most characterized prokaryotic sialidases are from organisms that are pathogenic or commensal with mammals. However, in this study, we used functional metagenomic screening to seek microbial sialidases encoded by environmental DNA isolated from an extreme ecological niche, a thermal spring. Using recombinant expression of potential exosialidase candidates and a fluorogenic sialidase substrate, we discovered an exosialidase having no homology to known sialidases. Phylogenetic analysis indicated that this protein is a member of a small family of bacterial proteins of previously unknown function. Proton NMR revealed that this enzyme functions via an inverting catalytic mechanism, a biochemical property that is distinct from those of known exosialidases. This unique inverting exosialidase defines a new CAZy glycoside hydrolase family we have designated GH156.

scholarly journals Distribution of emm type and antibiotic susceptibility of group A streptococci causing invasive and noninvasive disease

2008 ◽  
Vol 57 (11) ◽  
pp. 1383-1388 ◽  
Author(s):  
Takeaki Wajima ◽  
Somay Y. Murayama ◽  
Katsuhiko Sunaoshi ◽  
Eiichi Nakayama ◽  
Keisuke Sunakawa ◽  
...  
Keyword(s):  
Streptococcus Pyogenes ◽  
Macrolide Antibiotic ◽  
Group A Streptococcus ◽  
Acute Otitis Media ◽  
Toxic Shock ◽  
Medical Institutions ◽  
Invasive Infections ◽  
Group A ◽  
Resistant Strains ◽  
Emm Type

To determine the prevalence of macrolide antibiotic and levofloxacin resistance in infections with Streptococcus pyogenes (group A streptococcus or GAS), strains were collected from 45 medical institutions in various parts of Japan between October 2003 and September 2006. Four hundred and eighty-two strains from patients with GAS infections were characterized genetically. Strains were classified into four groups according to the type of infection: invasive infections (n=74) including sepsis, cellulitis and toxic-shock-like syndrome; acute otitis media (AOM; n=23); abscess (n=53); and pharyngotonsillitis (n=332). Among all strains, 32 emm types were identified; emm1 was significantly more common in invasive infections (39.2 %) and AOM (43.5 %) than in abscesses (3.8 %) or pharyngotonsillitis (10.2 %). emm12 and emm4 each accounted for 23.5 % of pharyngotonsillitis cases. Susceptibility of GAS strains to eight β-lactam agents was excellent, with MICs of 0.0005–0.063 μg ml−1. Macrolide-resistant strains accounted for 16.2 % of all strains, while the percentages of strains possessing the resistance genes erm(A), erm(B) and mef(A) were 2.5 %, 6.2 % and 7.5 %, respectively. Although no strains with high resistance to levofloxacin were found, strains with an MIC of 2–4 μg ml−1 (17.4 %) had amino acid substitutions at either Ser-79 or Asp-83 in ParC. These levofloxacin-intermediately resistant strains included 16 emm types, but macrolide-resistant strains were more likely than others to represent certain emm types.

scholarly journals Two exo-β-D-glucosaminidases/exochitosanases from actinomycetes define a new subfamily within family 2 of glycoside hydrolases

2006 ◽  
Vol 394 (3) ◽  
pp. 675-686 ◽  
Author(s):  
Nathalie Côté ◽  
Alain Fleury ◽  
Émilie Dumont-Blanchette ◽  
Tamo Fukamizo ◽  
Masaru Mitsutomi ◽  
...  
Keyword(s):  
Glycoside Hydrolase ◽  
Catalytic Mechanism ◽  
Pcr Primers ◽  
Amino Acid Sequences ◽  
Glycoside Hydrolases ◽  
Cloning And Expression ◽  
Streptomyces Avermitilis ◽  
Gene Cloning And Expression ◽  
Glycoside Hydrolase Family ◽  
Sequence Alignments

A GlcNase (exo-β-D-glucosaminidase) was purified from culture supernatant of Amycolatopsis orientalis subsp. orientalis grown in medium with chitosan. The enzyme hydrolysed the terminal GlcN (glucosamine) residues in oligomers of GlcN with transglycosylation observed at late reaction stages. 1H-NMR spectroscopy revealed that the enzyme is a retaining glycoside hydrolase. The GlcNase also behaved as an exochitosanase against high-molecular-mass chitosan with Km and kcat values of 0.16 mg/ml and 2832 min−1. On the basis of partial amino acid sequences, PCR primers were designed and used to amplify a DNA fragment which then allowed the cloning of the GlcNase gene (csxA) associated with an open reading frame of 1032 residues. The GlcNase has been classified as a member of glycoside hydrolase family 2 (GH2). Sequence alignments identified a group of CsxA-related protein sequences forming a distinct GH2 subfamily. Most of them have been annotated in databases as putative β-mannosidases. Among these, the SAV1223 protein from Streptomyces avermitilis has been purified following gene cloning and expression in a heterologous host and shown to be a GlcNase with no detectable β-mannosidase activity. In CsxA and all relatives, a serine-aspartate doublet replaces an asparagine residue and a glutamate residue, which were strictly conserved in previously studied GH2 members with β-galactosidase, β-glucuronidase or β-mannosidase activity and shown to be directly involved in various steps of the catalytic mechanism. Alignments of several other GH2 members allowed the identification of yet another putative subfamily, characterized by a novel, serine-glutamate doublet at these positions.

Synthesis of Multicomponent Peptide-Based Vaccine Candidates against Group A Streptococcus

2017 ◽  
Vol 70 (2) ◽  
pp. 184
Author(s):  
Waleed M. Hussein ◽  
Jiaxin Xu ◽  
Pavla Simerska ◽  
Istvan Toth
Keyword(s):  
Vaccine Candidate ◽  
Group A Streptococcus ◽  
Cycloaddition Reaction ◽  
Bacterial Pathogen ◽  
T Helper ◽  
Toxic Shock ◽  
Helper Epitope ◽  
Invasive Infections ◽  
Group A ◽  
Universal Expression

Group A streptococcus (GAS; Streptococcus pyogenes), known as the ‘flesh-eating bacterium’, is a human bacterial pathogen that normally causes benign infections (e.g. sore throat and pyoderma), but is also responsible for severe invasive infections (e.g. ‘flesh-eating’ disease and toxic shock syndrome), heart disease, and kidney failure. A safe commercial GAS vaccine is yet to be developed. Individual GAS antigens demonstrate potential universal expression across all GAS serotypes (>200 known), with dramatically reduced concern for autoimmune complications, and compelling efficacy in preclinical testing in mice. In this study, we developed a stepwise conjugation strategy, copper-catalysed alkyne–azide cycloaddition reaction (CuAAC), followed by mercapto–maleimide conjugation, to synthesise a multiantigenic, self-adjuvanting, peptide-based vaccine candidate against GAS. This multiantigenic vaccine includes two GAS antigens, J8 and NS1, a T-helper epitope, PADRE, and a self-adjuvanting moiety, dipalmitoyl serine.

scholarly journals Playing With Fire: Proinflammatory Virulence Mechanisms of Group A Streptococcus

2021 ◽  
Vol 11 ◽  
Author(s):  
Shyra Wilde ◽  
Anders F. Johnson ◽  
Christopher N. LaRock
Keyword(s):  
Virulence Factors ◽  
Group A Streptococcus ◽  
Severe Disease ◽  
Fatal Outcome ◽  
Toxic Shock ◽  
Autoreactive Antibodies ◽  
Invasive Infections ◽  
Group A ◽  
Disease Understanding

Group A Streptococcus is an obligate human pathogen that is a major cause of infectious morbidity and mortality. It has a natural tropism for the oropharynx and skin, where it causes infections with excessive inflammation due to its expression of proinflammatory toxins and other virulence factors. Inflammation directly contributes to the severity of invasive infections, toxic shock syndrome, and the induction of severe post-infection autoimmune disease caused by autoreactive antibodies. This review discusses what is known about how the virulence factors of Group A Streptococcus induce inflammation and how this inflammation can promote disease. Understanding of streptococcal pathogenesis and the role of hyper-immune activation during infection may provide new therapeutic targets to treat the often-fatal outcome of severe disease.

Development of a DNA aptamer that binds specifically to group A Streptococcus serotype M3

2017 ◽  
Vol 63 (2) ◽  
pp. 160-168 ◽  
Author(s):  
Hanif Alfavian ◽  
Seyed Latif Mousavi Gargari ◽  
Samaneh Rasoulinejad ◽  
Arvin Medhat
Keyword(s):  
Group A Streptococcus ◽  
Dna Aptamer ◽  
Live Cells ◽  
Streptococcal Toxic Shock Syndrome ◽  
Toxic Shock ◽  
Apparent Dissociation Constant ◽  
Invasive Infections ◽  
Group A ◽  
High Degree ◽  
High Binding Affinity

Group A streptococcus (GAS) is an important Gram-positive pathogen that causes various human diseases ranging from peripheral lesions to invasive infections. The M protein is one of the main virulence factors present on the cell surface and is associated with invasive GAS infections. Compared with other M types, serotype M3 has a predominant role in lethal infections and demonstrates epidemic behaviors, including streptococcal toxic shock syndrome, bacteremia, and necrotizing fasciitis. Traditional methods for M typing are time-consuming, tedious, contradictory, and generally restricted to reference laboratories. Therefore, development of a new M-typing technique is needed. Aptamers with the ability to detect their target with a high degree of accuracy and specificity can be ideal candidates for specific M-typing of Streptococcus pyogenes. In this study DNA aptamers with a high binding affinity towards S. pyogenes serotype M3 were selected through 12 iterative rounds of the Systematic Evolution of Ligands by EXponential (SELEX) enrichment procedure using live cells as a target. We monitored the progress of the SELEX procedure by flow cytometry analysis. Of several aptamer sequences analyzed, 12L18A showed the highest binding efficiency towards S. pyogenes type M3, with an apparent dissociation constant (Kd) of 7.47 ± 1.72 pmol/L being the lowest. Therefore the isolated aptamer can be used in any tool, such as a biosensor, for the detection of S. pyogenes and can be used in the development of a novel M-typing system.

Diverse disease processes of group A Streptococcus infection including severe invasive infections among members of a family

2021 ◽  
Vol 14 (4) ◽  
pp. e241339
Author(s):  
Kaori Amari ◽  
Masaki Tago ◽  
Naoko E Katsuki ◽  
Shu-ichi Yamashita
Keyword(s):  
Septic Shock ◽  
Distress Syndrome ◽  
Clinical Course ◽  
Group A Streptococcus ◽  
Bloody Stool ◽  
Laryngeal Oedema ◽  
Invasive Infections ◽  
Group A ◽  
The Right ◽  
Close Contacts

We herein report three cases of group A Streptococcus (GAS) infection in a family. Patient 1, a 50-year-old woman, was transferred to our hospital in shock with acute respiratory distress syndrome, swelling in the right neck and erythemata on both lower extremities. She required intubation because of laryngeal oedema. At the same time, patient 2, a 48-year-old man, was admitted because of septic shock, pneumonia and a pulmonary abscess. Five days later, patient 3, a 91-year-old woman, visited our clinic with bloody stool. All three patients were cured by antibiotics, and GAS was detected by specimen cultures. During these patients’ clinical course, an 84-year-old woman was found dead at home after having been diagnosed with type A influenza. All four patients lived in the same apartment. The GAS genotypes detected in the first three patients were identical. When treating patients with GAS, appropriate management of close contacts is mandatory.

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