Journal Article


Marie-Pierre Chapot-Chartier
Yann Guérardel
Saulius Kulakauskas
Douwe van Sinderen
Jennifer Mahony
Stuart Ainsworth
Christine Péchoux
Sylviane Furlan
Simon Palussière
Efstathios Giaouris
and 5 others



lactococcus lactis lactococcus cell wall hr mas nmr polysaccharides rhamnan high resolution nuclear magnetic resonance

Another brick in the wall: a rhamnan polysaccharide trapped inside peptidoglycan of Lactococcus lactis (2017)

Abstract 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.
Collections Ireland -> University College Cork -> APC Microbiome Institute
Ireland -> University College Cork -> College of Science, Engineering and Food Science
Ireland -> University College Cork -> APC Microbiome Institute- Journal Articles
Ireland -> University College Cork -> Microbiology
Ireland -> University College Cork -> Research Institutes and Centres
Ireland -> University College Cork -> Microbiology - Journal Articles

Full list of authors on original publication

Marie-Pierre Chapot-Chartier, Yann Guérardel, Saulius Kulakauskas, Douwe van Sinderen, Jennifer Mahony, Stuart Ainsworth, Christine Péchoux, Sylviane Furlan, Simon Palussière, Efstathios Giaouris and 5 others

Experts in our system

Marie-Pierre Chapot-Chartier
University College Cork
Douwe van Sinderen
University College Cork
Total Publications: 144
Jennifer Mahony
University College Cork
Total Publications: 87
Stuart Ainsworth
University College Cork