The Lack of the Essential LptC Protein in the Trans-Envelope Lipopolysaccharide Transport Machine Is Circumvented by Suppressor Mutations in LptF, an Inner Membrane Component of the Escherichia coli Transporter

Handle URI:
http://hdl.handle.net/10754/622034
Title:
The Lack of the Essential LptC Protein in the Trans-Envelope Lipopolysaccharide Transport Machine Is Circumvented by Suppressor Mutations in LptF, an Inner Membrane Component of the Escherichia coli Transporter
Authors:
Benedet, Mattia; Falchi, Federica A.; Puccio, Simone; Di Benedetto, Cristiano; Peano, Clelia; Polissi, Alessandra; Deho, Gianni
Abstract:
The lipopolysaccharide (LPS) transport (Lpt) system is responsible for transferring LPS from the periplasmic surface of the inner membrane (IM) to the outer leaflet of the outer membrane (OM), where it plays a crucial role in OM selective permeability. In E. coli seven essential proteins are assembled in an Lpt trans-envelope complex, which is conserved in gamma-Proteobacteria. LptBFG constitute the IMABC transporter, LptDE form the OM translocon for final LPS delivery, whereas LptC, an IM-anchored protein with a periplasmic domain, interacts with the IM ABC transporter, the periplasmic protein LptA, and LPS. Although essential, LptC can tolerate several mutations and its role in LPS transport is unclear. To get insights into the functional role of LptC in the Lpt machine we searched for viable mutants lacking LptC by applying a strong double selection for lptC deletion mutants. Genome sequencing of viable Delta lptC mutants revealed single amino acid substitutions at a unique position in the predicted large periplasmic domain of the IM component LptF (LptF(SupC)). In complementation tests, lptF(SupC) mutants suppress lethality of both Delta lptC and lptC conditional expressionmutants. Our data show that mutations in a specific residue of the predicted LptF periplasmic domain can compensate the lack of the essential protein LptC, implicate such LptF domain in the formation of the periplasmic bridge between the IM and OM complexes, and suggest that LptC may have evolved to improve the performance of an ancestral six-component Lpt machine.
KAUST Department:
Biological and Environmental Sciences and Engineering (BESE) Division
Citation:
Benedet M, Falchi FA, Puccio S, Di Benedetto C, Peano C, et al. (2016) The Lack of the Essential LptC Protein in the Trans-Envelope Lipopolysaccharide Transport Machine Is Circumvented by Suppressor Mutations in LptF, an Inner Membrane Component of the Escherichia coli Transporter. PLOS ONE 11: e0161354. Available: http://dx.doi.org/10.1371/journal.pone.0161354.
Publisher:
Public Library of Science (PLoS)
Journal:
PLOS ONE
Issue Date:
16-Aug-2016
DOI:
10.1371/journal.pone.0161354
Type:
Article
ISSN:
1932-6203
Sponsors:
This work was supported by Fondazione per la Ricerca sulla Fibrosi Cistica (http://www.fibrosicisticaricerca.it/) (grant FFC#13/2010 to AP) and by Regione Lombardia-MIUR (http://www.regione.lombardia.it; http://www.istruzione.it), project ID 30190679 (to GD). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Additional Links:
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0161354
Appears in Collections:
Articles; Biological and Environmental Sciences and Engineering (BESE) Division

Full metadata record

DC FieldValue Language
dc.contributor.authorBenedet, Mattiaen
dc.contributor.authorFalchi, Federica A.en
dc.contributor.authorPuccio, Simoneen
dc.contributor.authorDi Benedetto, Cristianoen
dc.contributor.authorPeano, Cleliaen
dc.contributor.authorPolissi, Alessandraen
dc.contributor.authorDeho, Giannien
dc.date.accessioned2016-12-18T13:36:59Z-
dc.date.available2016-12-18T13:36:59Z-
dc.date.issued2016-08-16en
dc.identifier.citationBenedet M, Falchi FA, Puccio S, Di Benedetto C, Peano C, et al. (2016) The Lack of the Essential LptC Protein in the Trans-Envelope Lipopolysaccharide Transport Machine Is Circumvented by Suppressor Mutations in LptF, an Inner Membrane Component of the Escherichia coli Transporter. PLOS ONE 11: e0161354. Available: http://dx.doi.org/10.1371/journal.pone.0161354.en
dc.identifier.issn1932-6203en
dc.identifier.doi10.1371/journal.pone.0161354en
dc.identifier.urihttp://hdl.handle.net/10754/622034-
dc.description.abstractThe lipopolysaccharide (LPS) transport (Lpt) system is responsible for transferring LPS from the periplasmic surface of the inner membrane (IM) to the outer leaflet of the outer membrane (OM), where it plays a crucial role in OM selective permeability. In E. coli seven essential proteins are assembled in an Lpt trans-envelope complex, which is conserved in gamma-Proteobacteria. LptBFG constitute the IMABC transporter, LptDE form the OM translocon for final LPS delivery, whereas LptC, an IM-anchored protein with a periplasmic domain, interacts with the IM ABC transporter, the periplasmic protein LptA, and LPS. Although essential, LptC can tolerate several mutations and its role in LPS transport is unclear. To get insights into the functional role of LptC in the Lpt machine we searched for viable mutants lacking LptC by applying a strong double selection for lptC deletion mutants. Genome sequencing of viable Delta lptC mutants revealed single amino acid substitutions at a unique position in the predicted large periplasmic domain of the IM component LptF (LptF(SupC)). In complementation tests, lptF(SupC) mutants suppress lethality of both Delta lptC and lptC conditional expressionmutants. Our data show that mutations in a specific residue of the predicted LptF periplasmic domain can compensate the lack of the essential protein LptC, implicate such LptF domain in the formation of the periplasmic bridge between the IM and OM complexes, and suggest that LptC may have evolved to improve the performance of an ancestral six-component Lpt machine.en
dc.description.sponsorshipThis work was supported by Fondazione per la Ricerca sulla Fibrosi Cistica (http://www.fibrosicisticaricerca.it/) (grant FFC#13/2010 to AP) and by Regione Lombardia-MIUR (http://www.regione.lombardia.it; http://www.istruzione.it), project ID 30190679 (to GD). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.en
dc.publisherPublic Library of Science (PLoS)en
dc.relation.urlhttp://journals.plos.org/plosone/article?id=10.1371/journal.pone.0161354en
dc.rightsThis is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.en
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/en
dc.titleThe Lack of the Essential LptC Protein in the Trans-Envelope Lipopolysaccharide Transport Machine Is Circumvented by Suppressor Mutations in LptF, an Inner Membrane Component of the Escherichia coli Transporteren
dc.typeArticleen
dc.contributor.departmentBiological and Environmental Sciences and Engineering (BESE) Divisionen
dc.identifier.journalPLOS ONEen
dc.eprint.versionPublisher's Version/PDFen
dc.contributor.institutionDipartimento di Bioscienze, Università degli Studi di Milano, Milan, Italyen
dc.contributor.institutionCentre for Integrative Biology, Università degli Studi di Trento, Trento, Italyen
dc.contributor.institutionScuola di Dottorato in Medicina Molecolare e Traslazionale, Università degli Studi di Milano, Segrate, Italyen
dc.contributor.institutionIstituto di Tecnologie Biomediche, Consiglio Nazionale Delle Ricerche, Milan, Italyen
dc.contributor.institutionDipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, Milan, Italyen
dc.contributor.institutionDipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italyen
kaust.authorDi Benedetto, Cristianoen
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