Show simple item record

dc.contributor.authorMoradali, M Fata
dc.contributor.authorDonati, Ivan
dc.contributor.authorSims, Ian M
dc.contributor.authorGhods, Shirin
dc.contributor.authorRehm, Bernd HA
dc.date.accessioned2018-07-10T01:30:30Z
dc.date.available2018-07-10T01:30:30Z
dc.date.issued2015
dc.identifier.issn2150-7511
dc.identifier.doi10.1128/mBio.00453-15
dc.identifier.urihttp://hdl.handle.net/10072/342776
dc.description.abstractThe molecular mechanisms of alginate polymerization/modification/secretion by a proposed envelope-spanning multiprotein complex are unknown. Here, bacterial two-hybrid assays and pulldown experiments showed that the catalytic subunit Alg8 directly interacts with the proposed copolymerase Alg44 while embedded in the cytoplasmic membrane. Alg44 additionally interacts with the lipoprotein AlgK bridging the periplasmic space. Site-specific mutagenesis of Alg44 showed that protein-protein interactions and stability were independent of conserved amino acid residues R17 and R21, which are involved in c-di-GMP binding, the N-terminal PilZ domain, and the C-terminal 26 amino acids. Site-specific mutagenesis was employed to investigate the c-di-GMP-mediated activation of alginate polymerization by the PilZAlg44 domain and Alg8. Activation was found to be different from the proposed activation mechanism for cellulose synthesis. The interactive role of Alg8, Alg44, AlgG (epimerase), and AlgX (acetyltransferase) on alginate polymerization and modification was studied by using site-specific deletion mutants, inactive variants, and overproduction of subunits. The compositions, molecular masses, and material properties of resulting novel alginates were analyzed. The molecular mass was reduced by epimerization, while it was increased by acetylation. Interestingly, when overproduced, Alg44, AlgG, and the nonepimerizing variant AlgG(D324A) increased the degree of acetylation, while epimerization was enhanced by AlgX and its nonacetylating variant AlgX(S269A). Biofilm architecture analysis showed that acetyl groups promoted cell aggregation while nonacetylated polymannuronate alginate promoted stigmergy. Overall, this study sheds new light on the arrangement of the multiprotein complex involved in alginate production. Furthermore, the activation mechanism and the interplay between polymerization and modification of alginate were elucidated.
dc.description.peerreviewedYes
dc.languageEnglish
dc.language.isoeng
dc.publisherAmerican Society for Microbiology
dc.relation.ispartofpagefrome00453-15-1
dc.relation.ispartofpagetoe00453-15-17
dc.relation.ispartofissue3
dc.relation.ispartofjournalmBio
dc.relation.ispartofvolume6
dc.subject.fieldofresearchMicrobiology
dc.subject.fieldofresearchMicrobiology not elsewhere classified
dc.subject.fieldofresearchcode3107
dc.subject.fieldofresearchcode310799
dc.titleAlginate polymerization and modification are linked in pseudomonas aeruginosa
dc.typeJournal article
dc.type.descriptionC1 - Articles
dc.type.codeC - Journal Articles
dcterms.licensehttps://creativecommons.org/licenses/by-nc-sa/3.0/
dc.description.versionVersion of Record (VoR)
gro.rights.copyright© 2015 Fata Moradali et al. This is an open-access article distributed under the terms of the Creative Commons Attribution-Noncommercial-ShareAlike 3.0 Unported license, which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original author and source are credited.
gro.hasfulltextFull Text
gro.griffith.authorRehm, Bernd


Files in this item

This item appears in the following Collection(s)

  • Journal articles
    Contains articles published by Griffith authors in scholarly journals.

Show simple item record