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The mechanisms by which bacterial cells generate helical cell shape and its functional role are poorly understood. Helical shape of the human pathogen Helicobacter pylori may facilitate penetration of the thick gastric mucus where it replicates. We identified four genes required for helical shape: three LytM peptidoglycan endopeptidase homologs (csd1-3) and a ccmA homolog. Surrounding the cytoplasmic membrane of most bacteria, the peptidoglycan (murein) sacculus is a meshwork of glycan strands joined by peptide crosslinks. Intact cells and isolated sacculi from mutants lacking any single csd gene or ccmA formed curved rods and showed increased peptidoglycan crosslinking. Quantitative morphological analyses of multiple-gene deletion mutants revealed each protein uniquely contributes to a shape-generating pathway. This pathway is required for robust colonization of the stomach in spite of normal directional motility. Our findings suggest that the coordinated action of multiple proteins relaxes peptidoglycan crosslinking, enabling helical cell curvature and twist.
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http://dx.doi.org/10.1016/j.cell.2010.03.046 | DOI Listing |
bioRxiv
July 2025
Department of Immunology and Microbiology, University of Colorado School - Anschutz Medical Campus, School of Medicine, Aurora, CO, USA, 80045.
is a Gram-positive bacterium that is resident to the intestines of animals including humans. is also an opportunistic pathogen that causes multidrug resistant (MDR) infections. Bacteriophages (phages) have been proposed as therapeutics for the treatment of MDR infections, however, an obstacle for phage therapy is the emergence of phage resistance.
View Article and Find Full Text PDFJ Mol Biol
August 2025
State Key Laboratory of Virology and Biosafety, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China; University of Chinese Academy of Sciences, Beijing 100049, China; Hubei Jiangxia Laboratory, Wuhan 430200, China. Electronic address:
Phage-derived lysins represent a novel, non-traditional therapeutic agent against multidrug-resistant bacteria. However, engineering lysins with broad host range remain poorly addressed. Previously, we reported that the chimeric lysin ClyR, which harbors the CHAP catalytic domain of PlyC lysin (PlyCAC) and the SH3b cell-wall binding domain of PlySs2 lysin (PlySb), exhibits an expanded host range.
View Article and Find Full Text PDFNat Commun
July 2025
INSERM ERL 1336, UMR 8228, Sorbonne Université-ENS-PSL-CNRS, Paris, France.
In Escherichia coli, lateral cell-wall expansion during growth occurs by cross-linking of new glycan strands to the existing peptidoglycan network. However, it is unclear whether the same mechanism applies to other rod-shaped bacteria. Here, we use cell imaging and mass spectrometry analysis of isotopically labeled peptidoglycan to study this process in the Gram-positive bacterium Bacillus subtilis.
View Article and Find Full Text PDFUnlabelled: The bacterial cell envelope is a critical interface with the environment, particularly in Gram-negative species where the outer membrane and peptidoglycan layers coordinate to maintain structural integrity and resist turgor. Although this coordination is essential for survival, the molecular mechanisms linking outer membrane and peptidoglycan homeostasis remain poorly understood. LD-transpeptidases (LDTs) are enzymes that crosslink peptides in peptidoglycan and incorporate D-amino acids, but their physiological roles are not fully defined.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
July 2025
Council of Scientific and Industrial Research-Centre for Cellular and Molecular Biology, Hyderabad, Telangana 500007, India.
Peptidoglycan (PG), a defining feature of the bacterial cell envelope, is crucial for cell integrity and morphology. PG is a macromolecular mesh consisting of glycan polymers crosslinked by short peptides encasing the cytoplasmic membrane. PG peptides contain two to five amino acids of both L- and D-configuration, with a conserved L-alanine residue at the first position in most bacteria.
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