Titre :

Another Brick in the Wall: a Rhamnan Polysaccharide Trapped inside Peptidoglycan of Lactococcus lactis

Auteur(s) :

Sadovskaya, Irina [Auteur]
Université du Littoral Côte d'Opale [ULCO]
Institut Charles Viollette (ICV) - EA 7394 [ICV]
Vinogradov, Evgeny [Auteur]
National Research Council of Canada [NRC]
Courtin, Pascal [Auteur]
MICrobiologie de l'ALImentation au Service de la Santé [MICALIS]
Armalyte, Julija [Auteur]
MICrobiologie de l'ALImentation au Service de la Santé [MICALIS]
Meyrand, Mickael [Auteur]
MICrobiologie de l'ALImentation au Service de la Santé [MICALIS]
Giaouris, Efstathios [Auteur]
MICrobiologie de l'ALImentation au Service de la Santé [MICALIS]
Palussière, Simon [Auteur]
MICrobiologie de l'ALImentation au Service de la Santé [MICALIS]
Furlan, Sylviane [Auteur]
MICrobiologie de l'ALImentation au Service de la Santé [MICALIS]
Péchoux, Christine [Auteur]
Génétique Animale et Biologie Intégrative [GABI]
Ainsworth, Stuart [Auteur]
University College Cork [UCC]
Mahony, Jennifer [Auteur]
University College Cork [UCC]
van Sinderen, Douwe [Auteur]
University College Cork [UCC]
Kulakauskas, Saulius [Auteur]
MICrobiologie de l'ALImentation au Service de la Santé [MICALIS]
Guerardel, Yann [Auteur]
Unité de Glycobiologie Structurale et Fonctionnelle (UGSF) - UMR 8576
Unité de Glycobiologie Structurale et Fonctionnelle - UMR 8576 [UGSF]
Chapot-Chartier, Marie-Pierre [Auteur]
MICrobiologie de l'ALImentation au Service de la Santé [MICALIS]

Titre de la revue :

mBio

Nom court de la revue :

MBio

Numéro :

8

Date de publication :

2017-09-12

ISSN :

2150-7511

Mot(s)-clé(s) en anglais :

Cell Wall
rhamnan
HR-MAS NMR
Polysaccharide
Lactococcus

Discipline(s) HAL :

Chimie/Chimie théorique et/ou physique

Résumé en anglais : [en]

Polysaccharides 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 ...
Lire la suite >Polysaccharides 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.IMPORTANCE In the cell wall of Gram-positive bacteria, the peptidoglycan sacculus is considered the major structural component, maintaining cell shape and integrity. It is decorated with other glycopolymers, including polysaccharides, the roles of which are not fully elucidated. In the ovococcus Lactococcus lactis, a polysaccharide with a different structure between strains forms a layer at the bacterial surface and acts as the receptor for various bacteriophages that typically exhibit a narrow host range. The present report describes the identification of a novel polysaccharide in the L. lactis cell wall, a rhamnan that is trapped inside the peptidoglycan and covalently bound to it. We propose a model of rhamnan synthesis based on an ABC transporter-dependent pathway. Rhamnan appears as a conserved component of the lactococcal cell wall playing an essential role in growth and division, thus highlighting the importance of polysaccharides in the cell wall integrity of Gram-positive ovococci.Lire moins >

Langue :

Anglais

Audience :

Non spécifiée

Établissement(s) :

CNRS
INRA
ISA
Univ. Artois
Univ. Littoral Côte d’Opale
Université de Lille

Collections :

• BioEcoAgro - UMR-T 1158
• Unité de Glycobiologie Structurale et Fonctionnelle (UGSF) - UMR 8576

Équipe(s) de recherche :

Chemical Glycobiology

Date de dépôt :

2020-02-12T15:11:14Z
2021-03-10T10:03:33Z