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Structure of the cell envelope of corynebacteria: importance of the non-covalently bound lipids in the formation of the cell wall permeability barrier and fracture plane

Puech, Virginie and Chami, Mohamed and Lemassu, Anne and Lanéelle, Marie-Antoinette and Schiffler, Bettina and Gounon, Pierre and Bayan, Nicolas and Benz, Roland and Daffé, Mamadou. (2001) Structure of the cell envelope of corynebacteria: importance of the non-covalently bound lipids in the formation of the cell wall permeability barrier and fracture plane. Microbiology, 147 (5). pp. 1365-1382.

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Official URL: https://edoc.unibas.ch/93671/

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Abstract

With the recent success of the heterologous expression of mycobacterial antigens in corynebacteria, in addition to the importance of these bacteria in biotechnology and medicine, a better understanding of the structure of their cell envelopes was needed. A combination of molecular compositional analysis, ultrastructural appearance and freeze-etch electron microscopy study was used to arrive at a chemical model, unique to corynebacteria but consistent with their phylogenetic relatedness to mycobacteria and other members of the distinctive suprageneric actinomycete taxon. Transmission electron microscopy and chemical analyses showed that the cell envelopes of the representative strains of corynebacteria examined consisted of (i) an outer layer composed of polysaccharides (primarily a high-molecular-mass glucan and arabinomannans), proteins, which include the mycoloyltransferase PS1, and lipids; (ii) a cell wall glycan core of peptidoglycan-arabinogalactan which may contain other sugar residues and was usually esterified by corynomycolic acids; and (iii) a typical plasma membrane bilayer. Freeze-etch electron microscopy showed that most corynomycolate-containing strains exhibited a main fracture plane in their cell wall and contained low-molecular-mass porins, while the fracture occurred within the plasma membrane of strains devoid of both corynomycolate and pore-forming proteins. Importantly, in most strains, the amount of cell wall-linked corynomycolates was not sufficient to cover the bacterial surface; interestingly, the occurrence of a cell wall fracture plane correlated with the amount of non-covalently bound lipids of the strains. Furthermore, these lipids were shown to spontaneously form liposomes, indicating that they may participate in a bilayer structure. Altogether, the data suggested that the cell wall permeability barrier in corynebacteria involved both covalently linked corynomycolates and non-covalently bound lipids of their cell envelopes.
Faculties and Departments:05 Faculty of Science > Departement Biozentrum > Former Organization Units Biozentrum > Structural Biology (Engel)
05 Faculty of Science > Departement Biozentrum > Services Biozentrum > BioEM Lab (Chami)
UniBasel Contributors:Chami, Mohamed
Item Type:Article, refereed
Article Subtype:Research Article
Publisher:Microbiology Society
ISSN:1350-0872
e-ISSN:1465-2080
Note:Publication type according to Uni Basel Research Database: Journal article
Identification Number:
Last Modified:21 Feb 2023 14:51
Deposited On:21 Feb 2023 14:51

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