{"doi":"10.1128/jb.00918-15","title":"AB\n            <sub>5</sub>\n            Preassembly Is Not Required for Shiga Toxin Activity","abstract":"<jats:title>ABSTRACT</jats:title>\n          <jats:p>\n            Shiga toxin (Stx)-producing\n            <jats:named-content xmlns:xlink=\"http://www.w3.org/1999/xlink\" content-type=\"genus-species\" xlink:type=\"simple\">Escherichia coli</jats:named-content>\n            (STEC) is a major cause of foodborne illness, including the life-threatening complication hemolytic-uremic syndrome. The German outbreak in 2011 resulted in nearly 4,000 cases of infection, with 54 deaths. Two forms of Stx, Stx1 and Stx2, differ in potency, and subtype Stx2a is most commonly associated with fatal human disease. Stx is considered to be an AB\n            <jats:sub>5</jats:sub>\n            toxin. The single A (enzymatically active) subunit inhibits protein synthesis by cleaving a catalytic adenine from the eukaryotic rRNA. The B (binding) subunit forms a homopentamer and mediates cellular association and toxin internalization by binding to the glycolipid globotriaosylceramide (Gb3). Both subunits are essential for toxicity. Here we report that unlike other AB\n            <jats:sub>5</jats:sub>\n            toxin family members, Stx is produced by STEC as unassembled A and B subunits. A preformed AB\n            <jats:sub>5</jats:sub>\n            complex is not required for cellular toxicity or\n            <jats:italic>in vivo</jats:italic>\n            toxicity to mice, and toxin assembly likely occurs at the cell membrane. We demonstrate that disruption of A- and B-subunit association by use of A-subunit peptides that lack enzymatic activity can protect mice from lethal doses of toxin. Currently, no treatments have been proven to be effective for hemolytic-uremic syndrome. Our studies demonstrate that agents that interfere with A- and B-subunit assembly may have therapeutic potential. Shiga toxin (Stx) produced by pathogenic\n            <jats:named-content xmlns:xlink=\"http://www.w3.org/1999/xlink\" content-type=\"genus-species\" xlink:type=\"simple\">Escherichia coli</jats:named-content>\n            is considered to be an AB\n            <jats:sub>5</jats:sub>\n            heterohexamer; however, no known mechanisms ensure AB\n            <jats:sub>5</jats:sub>\n            assembly. Stx released by\n            <jats:named-content xmlns:xlink=\"http://www.w3.org/1999/xlink\" content-type=\"genus-species\" xlink:type=\"simple\">E. coli</jats:named-content>\n            is not in the AB\n            <jats:sub>5</jats:sub>\n            conformation and assembles at the receptor interface. Thus, unassembled Stx can impart toxicity. This finding shows that preventing AB\n            <jats:sub>5</jats:sub>\n            assembly is a potential treatment for Stx-associated illnesses.\n          </jats:p>\n          <jats:p>\n            <jats:bold>IMPORTANCE</jats:bold>\n            Complications due to Shiga toxin are frequently fatal, and at present, supportive care is the only treatment option. Furthermore, antibiotic treatment is contraindicated due to the ability of antibiotics to amplify bacterial expression of Shiga toxin. We report, contrary to prevailing assumptions, that Shiga toxin produced by STEC circulates as unassembled A and B subunits at concentrations that are lethal to mice. Similar to the case for anthrax toxin, assembly occurs on receptors expressed on the surfaces of mammalian target cells. Disruption of Shiga toxin assembly by use of A-subunit peptides that lack enzymatic activity protects mice from lethal challenge with Shiga toxin, suggesting a new approach for development of therapeutics.\n          </jats:p>","journal":"Journal of Bacteriology","year":2016,"id":620293,"datarank":0.38474240361923057,"base_score":2.5649493574615367,"endowment":2.5649493574615367,"self_citation_contribution":0.38474240361923057,"citation_network_contribution":0.0,"self_endowment_contribution":0.38474240361923057,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":12,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":null,"is_data_producer":false,"deposit_databanks":null,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":null,"fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1601252,"name":"Sayali S. Karve","orcid":null,"position":1,"is_corresponding":false},{"id":456372,"name":"Suman Pradhan","orcid":"0000-0002-9596-8190","position":2,"is_corresponding":false},{"id":456373,"name":"Alison A. Weiss","orcid":"0000-0002-4726-8376","position":3,"is_corresponding":false},{"id":1601250,"name":"Christine A. Pellino","orcid":null,"position":0,"is_corresponding":false}],"reference_count":0,"raw_metadata":{"has_enrichment":true,"resolved":true,"title":"AB\n            <sub>5</sub>\n            Preassembly Is Not Required for Shiga Toxin Activity","abstract":"<jats:title>ABSTRACT</jats:title>\n          <jats:p>\n            Shiga toxin (Stx)-producing\n            <jats:named-content xmlns:xlink=\"http://www.w3.org/1999/xlink\" content-type=\"genus-species\" xlink:type=\"simple\">Escherichia coli</jats:named-content>\n            (STEC) is a major cause of foodborne illness, including the life-threatening complication hemolytic-uremic syndrome. The German outbreak in 2011 resulted in nearly 4,000 cases of infection, with 54 deaths. Two forms of Stx, Stx1 and Stx2, differ in potency, and subtype Stx2a is most commonly associated with fatal human disease. Stx is considered to be an AB\n            <jats:sub>5</jats:sub>\n            toxin. The single A (enzymatically active) subunit inhibits protein synthesis by cleaving a catalytic adenine from the eukaryotic rRNA. The B (binding) subunit forms a homopentamer and mediates cellular association and toxin internalization by binding to the glycolipid globotriaosylceramide (Gb3). Both subunits are essential for toxicity. Here we report that unlike other AB\n            <jats:sub>5</jats:sub>\n            toxin family members, Stx is produced by STEC as unassembled A and B subunits. A preformed AB\n            <jats:sub>5</jats:sub>\n            complex is not required for cellular toxicity or\n            <jats:italic>in vivo</jats:italic>\n            toxicity to mice, and toxin assembly likely occurs at the cell membrane. We demonstrate that disruption of A- and B-subunit association by use of A-subunit peptides that lack enzymatic activity can protect mice from lethal doses of toxin. Currently, no treatments have been proven to be effective for hemolytic-uremic syndrome. Our studies demonstrate that agents that interfere with A- and B-subunit assembly may have therapeutic potential. Shiga toxin (Stx) produced by pathogenic\n            <jats:named-content xmlns:xlink=\"http://www.w3.org/1999/xlink\" content-type=\"genus-species\" xlink:type=\"simple\">Escherichia coli</jats:named-content>\n            is considered to be an AB\n            <jats:sub>5</jats:sub>\n            heterohexamer; however, no known mechanisms ensure AB\n            <jats:sub>5</jats:sub>\n            assembly. Stx released by\n            <jats:named-content xmlns:xlink=\"http://www.w3.org/1999/xlink\" content-type=\"genus-species\" xlink:type=\"simple\">E. coli</jats:named-content>\n            is not in the AB\n            <jats:sub>5</jats:sub>\n            conformation and assembles at the receptor interface. Thus, unassembled Stx can impart toxicity. This finding shows that preventing AB\n            <jats:sub>5</jats:sub>\n            assembly is a potential treatment for Stx-associated illnesses.\n          </jats:p>\n          <jats:p>\n            <jats:bold>IMPORTANCE</jats:bold>\n            Complications due to Shiga toxin are frequently fatal, and at present, supportive care is the only treatment option. Furthermore, antibiotic treatment is contraindicated due to the ability of antibiotics to amplify bacterial expression of Shiga toxin. We report, contrary to prevailing assumptions, that Shiga toxin produced by STEC circulates as unassembled A and B subunits at concentrations that are lethal to mice. Similar to the case for anthrax toxin, assembly occurs on receptors expressed on the surfaces of mammalian target cells. Disruption of Shiga toxin assembly by use of A-subunit peptides that lack enzymatic activity protects mice from lethal challenge with Shiga toxin, suggesting a new approach for development of therapeutics.\n          </jats:p>","is_dataset_classified":null,"base_score":2.5649493574615367,"endowment":2.5649493574615367,"datacite_reuse_total":0,"file_count":0,"downloads":0,"views":0,"has_version_chain":false,"is_dataset":false,"is_oa":false,"pmid":"27002129","pmcid":"PMC4959293","openalex_id":"https://openalex.org/W2304754246","authors":[],"funders":[{"funder_name":"HHS | National Institutes of Health","grant_id":"U01AI075498","title":null},{"funder_name":"HHS | National Institutes of Health","grant_id":"R01 AI 064893","title":null},{"funder_name":"National Science Foundation","grant_id":"IGERT Predoctoral Fellowship","title":null},{"funder_name":"National Institutes of Health","grant_id":"5R01AI064893-03","title":"Shiga Toxin Production and Role in Pathogenesis"},{"funder_name":"National Institutes of Health","grant_id":"5U01AI075498-05","title":"Glycoconjugate based diagnostics for bacterial toxins"}],"total_grants":5,"fwci":1.9153,"citation_percentile":0.83942308,"influential_citations":0,"citation_trend":[{"year":2016,"count":1},{"year":2017,"count":3},{"year":2018,"count":2},{"year":2019,"count":1},{"year":2020,"count":2},{"year":2021,"count":2},{"year":2024,"count":1}],"oa_status":"bronze","license":"ASM Journals Non-Commercial TDM","oa_locations":[{"url":"https://jb.asm.org/content/jb/198/11/1621.full.pdf","host_type":"journal"},{"url":"https://jb.asm.org/content/jb/198/11/1621.full.pdf","host_type":"publisher"},{"url":"https://journals.asm.org/doi/pdf/10.1128/JB.00918-15","host_type":"publisher"},{"url":"https://doi.org/10.1128/jb.00918-15","host_type":"journal"},{"url":"https://pubmed.ncbi.nlm.nih.gov/27002129","host_type":"repository"},{"url":"https://www.ncbi.nlm.nih.gov/pmc/articles/4959293","host_type":"repository"},{"url":"https://dx.doi.org/10.1128/jb.00918-15","host_type":""}],"fields_of_study":["Escherichia coli research studies","Toxin Mechanisms and Immunotoxins","Monoclonal and Polyclonal Antibodies Research","0301 basic medicine","0303 health sciences","03 medical and health sciences"],"mesh_terms":["Amino Acid Sequence","Animals","Male","Models, Molecular","Protein Conformation","Protein Biosynthesis","Gene Expression Regulation, Bacterial","Catalytic Domain","Protein Subunits","Shiga Toxin 2","Mice","Shiga-Toxigenic Escherichia coli"],"keywords":["Shiga toxin","Biology","Shiga-like toxin","Toxin","Escherichia coli","Protein subunit","Microbiology","Biochemistry","Male","Models, Molecular","Shiga-Toxigenic Escherichia coli","Protein Conformation","Gene Expression Regulation, Bacterial","Shiga Toxin 2","Mice","Protein Subunits","Catalytic Domain","Protein Biosynthesis","Animals","Amino Acid Sequence"],"sdg_mappings":[{"sdg_number":3,"sdg_label":"3. 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