Dataset Information

Peptidoglycan O-acetylation is functionally related to cell wall biosynthesis and cell division in Streptococcus pneumoniae.

ABSTRACT: The peptidoglycan is a rigid matrix required to resist turgor pressure and to maintain the cellular shape. It is formed by linear glycan chains composed of N-acetylmuramic acid-(?-1,4)-N-acetylglucosamine (MurNAc-GlcNAc) disaccharides associated through cross-linked peptide stems. The peptidoglycan is continually remodelled by synthetic and hydrolytic enzymes and by chemical modifications, including O-acetylation of MurNAc residues that occurs in most Gram-positive and Gram-negative bacteria. This modification is a powerful strategy developed by pathogens to resist to lysozyme degradation and thus to escape from the host innate immune system but little is known about its physiological function. In this study, we have investigated to what extend peptidoglycan O-acetylation is involved in cell wall biosynthesis and cell division of Streptococcus pneumoniae. We show that O-acetylation driven by Adr protects the peptidoglycan of dividing cells from cleavage by the major autolysin LytA and occurs at the septal site. Our results support a function for Adr in the formation of robust and mature MurNAc O-acetylated peptidoglycan and infer its role in the division of the pneumococcus.

SUBMITTER: Bonnet J

PROVIDER: S-EPMC5696066 | biostudies-literature | 2017 Dec

REPOSITORIES: biostudies-literature

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Peptidoglycan O-acetylation is functionally related to cell wall biosynthesis and cell division in Streptococcus pneumoniae.

Bonnet Julie J Durmort Claire C Jacq Maxime M Mortier-Barrière Isabelle I Campo Nathalie N VanNieuwenhze Michael S MS Brun Yves V YV Arthaud Christopher C Gallet Benoit B Moriscot Christine C Morlot Cécile C Vernet Thierry T Di Guilmi Anne Marie AM

Molecular microbiology 20171026 5

The peptidoglycan is a rigid matrix required to resist turgor pressure and to maintain the cellular shape. It is formed by linear glycan chains composed of N-acetylmuramic acid-(β-1,4)-N-acetylglucosamine (MurNAc-GlcNAc) disaccharides associated through cross-linked peptide stems. The peptidoglycan is continually remodelled by synthetic and hydrolytic enzymes and by chemical modifications, including O-acetylation of MurNAc residues that occurs in most Gram-positive and Gram-negative bacteria. Th ...[more]

PMID: 28960579

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Project description:Streptococcus pneumoniae is a human commensal bacterium that causes serious diseases. Peptidoglycan (PG) is the critical component of bacteria that maintains cell shape, size, chaining, and turgor resistance. Because of its surface exposure and eubacterial-specific mechanism of biosynthesis, PG biosynthesis remains an outstanding target for discovery of new antibiotics to resistant “superbugs,” like S. pneumoniae. Pneumococcal PG biosynthesis is carried out by a balance of septal and peripheral (side-wall-like) PG synthesis mediated by bPBP2x and bPBP2b, respectively, that emanates from midcell regions. We selected for additional suppressor mutations, besides mltG, that eliminate the requirement for essential bPBP2b in peripheral PG synthesis. We found that mutations that inactivate a putative RNA binding protein, designated KhpA, suppressed the requirement for some, but not all of the essential proteins required for peripheral PG synthesis. KhpA was used as bait in co-IP experiments to demonstrate interactions with a second RNA binding protein, designated KhpB, in cells. Mutations in khpA or khpB phenocopy each other and result in slower growth rates, smaller cell size with normal aspect ratios, and induction of cell wall stress responses. RIP-Seq analyses confirmed KhpAB as RNA binding protein in cells. Another suppressor of Δpbp2b implicated induction of a cell division operon as a way to bypass the requirement for bPBP2b. We show that increased expression of this cell division operon occurs in ΔkhpAB mutants and that this induction is necessary and sufficient to account for suppression of Δpbp2b. Comparisons of relative transcript amounts and protein levels indicate that induction of this cell division operon in ΔkhpAB mutants occurs primarily at the post-transcriptional level. Together, our results show that KhpAB, which are virulence factors in S. pneumoniae and are conserved in other Gram-positive pathogens, acts as a new class of RNA binding protein, with properties analogous to Hfq in Gram-negative bacteria.

Dataset Information

Peptidoglycan O-acetylation is functionally related to cell wall biosynthesis and cell division in Streptococcus pneumoniae.

Publications

Peptidoglycan O-acetylation is functionally related to cell wall biosynthesis and cell division in Streptococcus pneumoniae.

Similar Datasets

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