Peptidoglycan architecture of Gram-positive bacteria by solid-state NMR

Abstract

Peptidoglycan is an essential component of cell wall in Gram-positive bacteria with unknown architecture. In this review, we summarize solid-state NMR approaches to address some of the unknowns in the Gram-positive bacteria peptidoglycan architecture: 1) peptidoglycan backbone conformation, 2) PG-lattice structure, 3) variations in the peptidoglycan architecture and composition, 4) the effects of peptidoglycan bridge-length on the peptidoglycan architecture in Fem mutants, 5) the orientation of glycan strands respect to the membrane, and 6) the relationship between the peptidoglycan structure and the glycopeptide antibiotic mode of action. Solid-state NMR analyses of S. aureus cell wall show that peptidoglycan chains are surprisingly ordered and densely packed. The peptidoglycan disaccharide backbone adopts 4-fold screw helical symmetry with the disaccharide unit periodicity of 40 Å. Peptidoglycan lattice in S. aureus cell wall is formed by cross-linked PG stems that have parallel orientations. The structural characterization of Fem-mutants of S. aureus with varying lengths of bridge structures suggests that the PG-bridge length is an important determining factor for the PG architecture.

Gram-Positive Bacteria are held at a Distance in the Colon Mucus by the Lectin-Like Protein Zg16

“…S1 B-D). Such terminal epitopes appear relatively frequently in peptidoglycan, although the amount differs depending on the bacterial species (12). The in silico docking suggests that ZG16 could bind to peptidoglycan both by glycan and amino acid moieties.…”

Bacterial cell wall composition and the influence of antibiotics by cell-wall and whole-cell NMR

“…Vancomycin, oritavancin and plusbacin-A 3 are some of the specific glycopeptide antibiotics that have been studied [46,48,67,79]. Although an entire review could be dedicated to these studies (two recent reviews did cover some of this work [28,39]), we briefly summarize some of the key discoveries and strategies here to highlight the extensive work and discoveries in this area. Two major strategies have been employed in efforts to dissect inhibitor modes of action.…”

“…We also discuss the discoveries regarding the modes of action of vancomycin analogues including oritavancin, and briefly address the reconsideration of the killing action of b-lactam antibiotics. Although not covered in this review, solid-state NMR has also been employed to investigate peptidoglycan architecture [28] as well as dynamics [29]. In addition, solid-state NMR approaches have helped to dissect the influences of antimicrobial peptides in disrupting membrane integrity in different lipid systems [30][31][32][33].…”

Analysis of the Aspergillus fumigatus Biofilm Extracellular Matrix by Solid-State Nuclear Magnetic Resonance Spectroscopy

“…Thus, despite the prevalent roles that biofilms play in human infection, there has been little reliable quantitative information available regarding biofilm matrix composition. Solid-state NMR spectroscopy is uniquely suited to study complex and insoluble biological materials (12) such as whole cells (13)(14)(15)(16)(17)(18), biofilms, and the extracellular matrix (19)(20)(21)(22). Solidstate NMR approaches can be used to quantify composition and to measure internuclear distances to determine parameters of architecture in such macromolecular assemblies and does not require soluble or crystalline samples (15).…”