A disulfide driven domain swap switches off the activity of Shigella IpaH9.8 E3 ligase.
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.
Seyedarabi
Arefeh
A
School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom. a.seyedarabi@qmul.ac.uk
Sullivan
James A
JA
Sasakawa
Chihiro
C
Pickersgill
Richard W
RW
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
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