Another brick in the wall: a rhamnan polysaccharide trapped inside peptidoglycan of Lactococcus lactis

dc.contributor.authorSadovskaya, Irina
dc.contributor.authorVinogradov, Evgeny
dc.contributor.authorCourtin, Pascal
dc.contributor.authorArmalyte, Julija
dc.contributor.authorMeyrand, Mickael
dc.contributor.authorGiaouris, Efstathios
dc.contributor.authorPalussière, Simon
dc.contributor.authorFurlan, Sylviane
dc.contributor.authorPéchoux, Christine
dc.contributor.authorAinsworth, Stuart
dc.contributor.authorMahony, Jennifer
dc.contributor.authorvan Sinderen, Douwe
dc.contributor.authorKulakauskas, Saulius
dc.contributor.authorGuérardel, Yann
dc.contributor.authorChapot-Chartier, Marie-Pierre
dc.contributor.funderAgence Nationale de la Recherche
dc.contributor.funderConseil Régional, Île-de-France
dc.contributor.funderInstitut National de la Recherche Agronomique
dc.contributor.funderScience Foundation Ireland
dc.description.abstractPolysaccharides are ubiquitous components of the Gram-positive bacterial cell wall. In Lactococcus lactis, a polysaccharide pellicle (PSP) forms a layer at the cell surface. The PSP structure varies among lactococcal strains; in L. lactis MG1363, the PSP is composed of repeating hexasaccharide phosphate units. Here, we report the presence of an additional neutral polysaccharide in L. lactis MG1363 that is a rhamnan composed of α-L-Rha trisaccharide repeating units. This rhamnan is still present in mutants devoid of the PSP, indicating that its synthesis can occur independently of PSP synthesis. High-resolution magic-angle spinning nuclear magnetic resonance (HR-MAS NMR) analysis of whole bacterial cells identified a PSP at the surface of wild-type cells. In contrast, rhamnan was detected only at the surface of PSP-negative mutant cells, indicating that rhamnan is located underneath the surface-exposed PSP and is trapped inside peptidoglycan. The genetic determinants of rhamnan biosynthesis appear to be within the same genetic locus that encodes the PSP biosynthetic machinery, except the gene tagO encoding the initiating glycosyltransferase. We present a model of rhamnan biosynthesis based on an ABC transporter-dependent pathway. Conditional mutants producing reduced amounts of rhamnan exhibit strong morphological defects and impaired division, indicating that rhamnan is essential for normal growth and division. Finally, a mutation leading to reduced expression of lcpA, encoding a protein of the LytR-CpsA-Psr (LCP) family, was shown to severely affect cell wall structure. In lcpA mutant cells, in contrast to wild-type cells, rhamnan was detected by HR-MAS NMR, suggesting that LcpA participates in the attachment of rhamnan to peptidoglycan.en
dc.description.sponsorshipAgence Nationale de la Recherche (“Lactophages” (ANR-11-BSV8-004-01)en
dc.description.statusPeer revieweden
dc.description.versionPublished Versionen
dc.identifier.citationSadovskaya, I., Vinogradov, E., Courtin, P., Armalyte, J., Meyrand, M., Giaouris, E., Palussière, S., Furlan, S., Péchoux, C., Ainsworth, S., Mahony, J., van Sinderen, D., Kulakauskas, S., Guérardel, Y. and Chapot-Chartier, M.-P. (2017) 'Another brick in the wall: a rhamnan polysaccharide trapped inside peptidoglycan of Lactococcus lactis', mBio, 8(5), e01303-17 (16pp). doi: 10.1128/mBio.01303-17en
dc.publisherAmerican Society for Microbiologyen
dc.relation.projectinfo:eu-repo/grantAgreement/SFI/SFI Technology and Innovation Development Award (TIDA)/14/TIDA/2287/IE/Next generation diagnostic tools for problematic dairy bacteriophages/
dc.relation.projectinfo:eu-repo/grantAgreement/SFI/SFI Starting Investigator Research Grant (SIRG)/15/SIRG/3430/IE/Phage-host interactome of the dairy bacterium Streptococcus thermophilus (PHIST)/
dc.relation.projectinfo:eu-repo/grantAgreement/SFI/SFI Investigator Programme/13/IA/1953/IE/Functional analysis of the host adsorption and DNA injection processes of a lactococcal bacteriophage/
dc.rights© 2017, Sadovskaya et al. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license.en
dc.subjectHR-MAS NMRen
dc.subjectCell wallen
dc.titleAnother brick in the wall: a rhamnan polysaccharide trapped inside peptidoglycan of Lactococcus lactisen
dc.typeArticle (peer-reviewed)en
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