A dual-chain assembly pathway generates the high structural diversity of cell-wall polysaccharides in Lactococcus lactis .

Autor:	Theodorou I; School of Microbiology, University College Cork, Western Road, Cork, Ireland.; APC Microbiome Ireland, University College Cork, Western Road, Cork, Ireland., Courtin P; Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France., Palussière S; Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France., Kulakauskas S; Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France., Bidnenko E; Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France., Péchoux C; INRA, UMR 1313 Génétique Animale et Biologie Intégrative (GABI), Plate-forme MIMA2, 78350 Jouy-en-Josas, France., Fenaille F; CEA, Institut Joliot, Service de Pharmacologie et d'Immunoanalyse, UMR 0496, Laboratoire d'Etude du Métabolisme des Médicaments, MetaboHUB-Paris, Université Paris-Saclay, 91191 Gif-sur-Yvette, France., Penno C; School of Microbiology, University College Cork, Western Road, Cork, Ireland.; APC Microbiome Ireland, University College Cork, Western Road, Cork, Ireland., Mahony J; School of Microbiology, University College Cork, Western Road, Cork, Ireland.; APC Microbiome Ireland, University College Cork, Western Road, Cork, Ireland., van Sinderen D; School of Microbiology, University College Cork, Western Road, Cork, Ireland d.vansinderen@ucc.ie.; APC Microbiome Ireland, University College Cork, Western Road, Cork, Ireland., Chapot-Chartier MP; Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France Marie-Pierre.Chapot-Chartier@inra.fr.
Jazyk:	angličtina
Zdroj:	The Journal of biological chemistry [J Biol Chem] 2019 Nov 15; Vol. 294 (46), pp. 17612-17625. Date of Electronic Publication: 2019 Oct 03.
DOI:	10.1074/jbc.RA119.009957
Abstrakt:	In Lactococcus lactis , cell-wall polysaccharides (CWPSs) act as receptors for many bacteriophages, and their structural diversity among strains explains, at least partially, the narrow host range of these viral predators. Previous studies have reported that lactococcal CWPS consists of two distinct components, a variable chain exposed at the bacterial surface, named polysaccharide pellicle (PSP), and a more conserved rhamnan chain anchored to, and embedded inside, peptidoglycan. These two chains appear to be covalently linked to form a large heteropolysaccharide. The molecular machinery for biosynthesis of both components is encoded by a large gene cluster, named cwps In this study, using a CRISPR/Cas-based method, we performed a mutational analysis of the cwps genes. MALDI-TOF MS-based structural analysis of the mutant CWPS combined with sequence homology, transmission EM, and phage sensitivity analyses enabled us to infer a role for each protein encoded by the cwps cluster. We propose a comprehensive CWPS biosynthesis scheme in which the rhamnan and PSP chains are independently synthesized from two distinct lipid-sugar precursors and are joined at the extracellular side of the cytoplasmic membrane by a mechanism involving a membrane-embedded glycosyltransferase with a GT-C fold. The proposed scheme encompasses a system that allows extracytoplasmic modification of rhamnan by complex substituting oligo-/polysaccharides. It accounts for the extensive diversity of CWPS structures observed among lactococci and may also have relevance to the biosynthesis of complex rhamnose-containing CWPSs in other Gram-positive bacteria. (© 2019 Theodorou et al.)
Databáze:	MEDLINE
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