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dc.contributor.authorGreene, Nicholas P
dc.contributor.authorCrow, Allister
dc.contributor.authorHughes, Colin
dc.contributor.authorKoronakis, Vassilis
dc.date.accessioned2015-06-09T14:54:33Z
dc.date.available2015-06-09T14:54:33Z
dc.date.issued2015-06-09
dc.identifier.citationGreene et al. Proceedings of the National Academy of Sciences of the United States of America PNAS (2015) Vol. 112, E3058-E3066. DOI: 10.1073/pnas.1503832112
dc.identifier.issn0027-8424
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/248372
dc.description.abstractSecreted pore-forming toxins of pathogenic Gram-negative bacteria such as Escherichia coli hemolysin (HlyA) insert into host-cell membranes to subvert signal transduction and induce apoptosis and cell lysis. Unusually, these toxins are synthesized in an inactive form that requires posttranslational activation in the bacterial cytosol. We have previously shown that the activation mechanism is an acylation event directed by a specialized acyl-transferase that uses acyl carrier protein (ACP) to covalently link fatty acids, via an amide bond, to specific internal lysine residues of the protoxin. We now reveal the 2.15-Å resolution X-ray structure of the 172-aa ApxC, a toxin-activating acyl-transferase (TAAT) from pathogenic Actinobacillus pleuropneumoniae. This determination shows that bacterial TAATs are a structurally homologous family that, despite indiscernible sequence similarity, form a distinct branch of the Gcn5-like N-acetyl transferase (GNAT) superfamily of enzymes that typically use acyl-CoA to modify diverse bacterial, archaeal, and eukaryotic substrates. A combination of structural analysis, small angle X-ray scattering, mutagenesis, and cross-linking defined the solution state of TAATs, with intermonomer interactions mediated by an N-terminal α-helix. Superposition of ApxC with substrate-bound GNATs, and assay of toxin activation and binding of acyl-ACP and protoxin peptide substrates by mutated ApxC variants, indicates the enzyme active site to be a deep surface groove.
dc.description.sponsorshipThis work was supported by UK Medical Research Council and the Wellcome Trust Grants (to C.H. and V.K.).
dc.languageEnglish
dc.language.isoen
dc.publisherProceedings of the National Academy of Sciences
dc.rightsAttribution-NonCommercial 2.0 UK: England & Wales
dc.rights.urihttp://creativecommons.org/licenses/by-nc/2.0/uk/
dc.subjecthemolysin
dc.subjectacyltransferase
dc.subjectposttranslational modification
dc.subjectX-ray crystallography
dc.subjectacyl carrier protein
dc.titleStructure of a bacterial toxin-activating acyltransferase.
dc.typeArticle
dc.description.versionThis is the author accepted manuscript. The final version is available from PNAS via http://dx.doi.org/10.1073/pnas.1503832112
prism.endingPageE3066
prism.publicationDate2015
prism.publicationNameProc Natl Acad Sci U S A
prism.startingPageE3058
prism.volume112
dc.rioxxterms.funderMRC
dc.rioxxterms.funderWellcome Trust
rioxxterms.versionofrecord10.1073/pnas.1503832112
rioxxterms.licenseref.urihttp://www.rioxx.net/licenses/all-rights-reserved
rioxxterms.licenseref.startdate2015-05-27
dc.contributor.orcidCrow, Allister [0000-0001-6856-5962]
dc.identifier.eissn1091-6490
rioxxterms.typeJournal Article/Review
pubs.funder-project-idMedical Research Council (G1001104)
pubs.funder-project-idWellcome Trust (093011/Z/10/Z)
pubs.funder-project-idWellcome Trust (101828/Z/13/Z)
cam.issuedOnline2015-05-27
rioxxterms.freetoread.startdate2015-11-27


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