Structure of the peptidoglycan of bacterial cell walls. I

Burge, R. E.; Fowler, Allan; Reaveley, D. A.

doi:10.1016/s0022-2836(77)80006-5

Cited by 82 publications

(32 citation statements)

References 61 publications

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“…During preparation of this manuscript two interesting papers on the same subject were published by Burge et al [34,35]. In accordance with our results these authors have reached the conclusion that chitin-like structures are impossible for the glycan chains of murein.…”

Section: Resultssupporting

confidence: 88%

On the Secondary and Tertiary Structure of Murein

Labischinski

Barnickel

Bradaczek

et al. 1979

European Journal of Biochemistry

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X-ray diffraction, density measurements, and stereochemical data were used in order to disclose the architecture of murein, the rigid component of almost all bacterial cell walls. Dry densities of 1.38 -1.39 g/cm3 were observed for Micrococcus luteus and Staphylococcus aureus. The X-ray data for gram-positive (S. uureiis, M . luteus) and gram-negative (Escherichia cofi) strains were almost identical, showing, in addition to some diffuse scattering with broad maxima corresponding to Bragg values of 0.22 and 0.45 nm, two sharp peaks indicating periodicities of about 0.7 and 0.94 nm. These latter periodicities were not found in whole bacteria but emerge immediately after breakage of the whole cells. In gram-positive species a weak oriented reflex at 4.2 nm appeared, while all other reflexes remain ring-shaped. Diffraction patterns obtained under the influence of humidity and certain metal ions showed strong variations in the position of the 0.45-nm ha1 0.These data, together with stereochemical considerations, invalidate the hitherto advanced models of a chitin-like structure of the glycan chains in murein. Instead, the following model proposed and discussed here is consistent with the experimental data. The structure is made up of layers, which in S. aureus and M . luteus are separated by about 4.2 nm. The layers are more or less randomly rotated against each other. The sugar chains run parallel to these layers and, hence, to the surface of the cell wall. They do not possess a twofold screw axis as in chitin or cellulose. Thus, the peptide strands protude from the glycan chain axis in different directions. The peptide strands seem to assume fairly rigid conformations and to be mainly responsible for the regular layer-like arrangement of murein.The main skeletal component of most bacterial cell walls is a unique polymer called peptidoglycan (murein). The murein of gram-positive bacteria has a multilayered arrangement and makes up about 50 % of the cell wall weight, whereas the murein of gramnegative bacteria is probably monolayered, representing only about 5-10% of the cell wall weight [l].The glycan chains are composed of alternating sequences of N-acetylglucosamine and N-acetylmuramic acid. The peptide part is built up by alternating Dand L-amino acids, including a y-bond for D-glutamic acid (Fig. 1) [2-41.The subunits are linked together by p(1-4)-glycosidic bonds in the glycan part and can be crossParts of this paper were presented at the IV. International Conference on Small-Angle Scattering of X-Rays and Neutrons in Gatlinburg/U.S. A., October 1977. linked by peptide bonds between the free amino group of the diamino acid and the carboxyl group of the D-alanine of another peptide strand which, in this case, loses its second D-alanine. The cross-linkage COCH..

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Section: Resultssupporting

confidence: 88%

On the Secondary and Tertiary Structure of Murein

Labischinski

Barnickel

Bradaczek

et al. 1979

European Journal of Biochemistry

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“…All Ramachandran maps were superimposed to give one final map for each disaccharide with an area of (a) 5,775 (b) 1,256 square degree with an energy less than 40 kJ/mol…”

Section: Resultsmentioning

confidence: 99%

Conformational behavior of the polysaccharide backbone of murein

1987

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SynopsisThe energetically possible conformations for the alternating heteropolysaccharide backbone of murein, consisting of N-acetylglucosamine and N-acetylmuramic acid, were calculated using an empirical approach. The calculations were carried out for regular as well as for random-chain polymers, resulting in a model for the saccharide strands featuring extended chains with a length increment of 0.98-1.02 nm per disaccharide unit and peptide attachment sites at every second saccharide residuum pointing into all directions with propagation angles of 80-100" between consecutive sites.

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“…Hence the PG cross-links would result in a 2D-planar sheet-like structure. The chitin-like model was subsequently abandoned for 4-fold screw helical symmetry with 40 Å periodicity, based on the X-ray diffraction analysis of isolated PG [26, 27] and of whole-cells S. aureus [27]. The 4-fold screw helical symmetry allows the successive PG-stems on a glycan chain to rotate 90° relative to previous stem, allowing cross-links to form in all four directions (Figure 3d).…”

Section: Pg Backbone Conformationmentioning

confidence: 99%

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

Kim

Chang

Singh

2015

Biochimica et Biophysica Acta (BBA) - Biomembranes

140

126

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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.

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Structure of the peptidoglycan of bacterial cell walls. I

Cited by 82 publications

References 61 publications

On the Secondary and Tertiary Structure of Murein

On the Secondary and Tertiary Structure of Murein

Conformational behavior of the polysaccharide backbone of murein

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

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