title: A disulfide driven domain swap switches off the activity of Shigella IpaH9.8 E3 ligase.
abstract: We show that the monomeric form of Shigella IpaH9.8 E3 ligase catalyses the ubiquitination of human U2AF35 in vitro, providing a molecular mechanism for the observed in vivo effect. We further discover that under non-reducing conditions IpaH9.8 undergoes a domain swap driven by the formation of a disulfide bridge involving the catalytic cysteine and that this dimer is unable to catalyse the ubiquitination of U2AF35. The crystal structure of the domain-swapped dimer is presented. The redox inactivation of IpaH9.8 could be a mechanism of regulating the activity of the IpaH9.8 E3 ligase in response to cell damage so that the host cell in which the bacteria resides is maintained in a benign state suitable for bacterial survival.
authors.affiliation: School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom. a.seyedarabi@qmul.ac.uk
authors.forename: Arefeh
authors.initials: A
authors.lastname: Seyedarabi
authors.forename: James A
authors.initials: JA
authors.lastname: Sullivan
authors.forename: Chihiro
authors.initials: C
authors.lastname: Sasakawa
authors.forename: Richard W
authors.initials: RW
authors.lastname: Pickersgill
mesh_terms: D000942:Antigens, Bacterial / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D003545:Cysteine / Q000737:chemistry; D019281:Dimerization; D004220:Disulfides / Q000737:chemistry; D006801:Humans; D066298:In Vitro Techniques; D008958:Models, Molecular; D009687:Nuclear Proteins / Q000378:metabolism; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012261:Ribonucleoproteins / Q000378:metabolism; D012763:Shigella flexneri / Q000201:enzymology* / Q000235:genetics; D000072668:Splicing Factor U2AF; D044767:Ubiquitin-Protein Ligases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D054875:Ubiquitination
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D004220:Disulfides; D009687:Nuclear Proteins; D011994:Recombinant Proteins; D012261:Ribonucleoproteins; D000072668:Splicing Factor U2AF; C076753:U2AF1 protein, human; C063500:ipaH protein, Shigella flexneri; D044767:Ubiquitin-Protein Ligases; D003545:Cysteine