Review: Conserved and variable structural features in the lipopolysaccharide of Pseudomonas aeruginosa

Knirel, Yuriy A.; Bystrova, Olga V.; Kocharova, Nina A.; Zähringer, Ulrich; Pier, Gerald B.

doi:10.1177/09680519060120060201

Cited by 54 publications

(94 citation statements)

References 69 publications

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“…In penta-acylated lipid A, there is no C3 C 10 (3-OH) primary chain ( Fig. S1) (30,32,33). In this study, the hexa-and the penta-acylated lipid A are denoted as PA-A and PA-B, respectively.…”

Section: Methodsmentioning

confidence: 99%

Bilayer Properties of Lipid A from Various Gram-Negative Bacteria

Kim

Patel

Park

et al. 2016

Biophysical Journal

132

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Lipid A is the lipid anchor of a lipopolysaccharide in the outer leaflet of the outer membrane of Gram-negative bacteria. In general, lipid A consists of two phosphorylated N-acetyl glucosamine and several acyl chains that are directly linked to the two sugars. Depending on the bacterial species and environments, the acyl chain number and length vary, and lipid A can be chemically modified with phosphoethanolamine, aminoarabinose, or glycine residues, which are key to bacterial pathogenesis. In this work, homogeneous lipid bilayers of 21 distinct lipid A types from 12 bacterial species are modeled and simulated to investigate the differences and similarities of their membrane properties. In addition, different neutralizing ion types (Ca 2þ , K þ , and Na þ ) are considered to examine the ion's influence on the membrane properties. The trajectory analysis shows that (1) the area per lipid is mostly correlated to the acyl chain number, and the area per lipid increases as a function of the acyl chain number; (2) the hydrophobic thickness is mainly determined by the average acyl chain length with slight dependence on the acyl chain number, and the hydrophobic thickness generally increases with the average acyl chain length; (3) a good correlation is observed among the area per lipid, hydrophobic thickness, and acyl chain order; and (4) although the influence of neutralizing ion types on the area per lipid and hydrophobic thickness is minimal, Ca 2þ stays longer on the membrane surface than K þ or Na þ , consequently leading to lower lateral diffusion and a higher compressibility modulus, which agrees well with available experiments.

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Section: Methodsmentioning

confidence: 99%

Bilayer Properties of Lipid A from Various Gram-Negative Bacteria

Kim

Patel

Park

et al. 2016

Biophysical Journal

132

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“…The O antigen protrudes into the environment and allows the bacterium to interact with its surroundings. There are 20 serotypes of P. aeruginosa (27), and 14 of those groups also produce the Aband saccharide known as common antigen, which is composed of D-rhamnose sugar polymer and consists of about 23 repeating units (6,47).LPS physical properties such as three-dimensional structure and number of repeating units contribute to bacterial adhesion (3,37,40). P. aeruginosa uses complicated biosynthetic mechanisms for assembly of LPS O antigen; this has been described extensively elsewhere (24).…”

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confidence: 99%

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Relating the Physical Properties of Pseudomonas aeruginosa Lipopolysaccharides to Virulence by Atomic Force Microscopy

et al. 2011

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Lipopolysaccharides (LPS) are an important class of macromolecules that are components of the outer membrane of Gram-negative bacteria such as Pseudomonas aeruginosa. P. aeruginosa contains two different sugar chains, the homopolymer common antigen (A band) and the heteropolymer O antigen (B band), which impart serospecificity. The characteristics of LPS are generally assessed after isolation rather than in the context of whole bacteria. Here we used atomic force microscopy (AFM) to probe the physical properties of the LPS of P. aeruginosa strain PA103 (serogroup O11) in situ. This strain contains a mixture of long and very long polymers of O antigen, regulated by two different genes. For this analysis, we studied the wild-type strain and four mutants, ⌬Wzz1 (producing only very long LPS), ⌬Wzz2 (producing only long LPS), D⌬M (with both the wzz1 and wzz2 genes deleted), and Wzy::GM (producing an LPS core oligosaccharide plus one unit of O antigen). Forces of adhesion between the LPS on these strains and the silicon nitride AFM tip were measured, and the Alexander and de Gennes model of steric repulsion between a flat surface and a polymer brush was used to calculate the LPS layer thickness (which we refer to as length), compressibility, and spacing between the individual molecules. LPS chains were longest for the wild-type strain and ⌬Wzz1, at 170.6 and 212.4 nm, respectively, and these values were not statistically significantly different from one another. Wzy::GM and D⌬M have reduced LPS lengths, at 34.6 and 37.7 nm, respectively. Adhesion forces were not correlated with LPS length, but a relationship between adhesion force and bacterial pathogenicity was found in a mouse acute pneumonia model of infection. The adhesion forces with the AFM probe were lower for strains with LPS mutations, suggesting that the wild-type strain is optimized for maximal adhesion. Our research contributes to further understanding of the role of LPS in the adhesion and virulence of P. aeruginosa.Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that can cause several different types of infections in both community and health care settings and is especially problematic for immunocompromised and cystic fibrosis patients, as well as burn victims (23,32). Surface structures on the bacterium are related to virulence and the ability to cause infections. They make it possible for P. aeruginosa to attach to a wide range of surfaces, as well as to interact with components of the host (20). The lipopolysaccharide (LPS) is an important virulence factor for P. aeruginosa (25). The structure of LPS consists of lipid A, which anchors the LPS to the outer membrane, the core oligosaccharide, and the highly variable Oantigen side chain, which consists of repeating saccharide units and confers serotype specificity to the bacterium. The O antigen protrudes into the environment and allows the bacterium to interact with its surroundings. There are 20 serotypes of P. aeruginosa (27), and 14 of those groups also produce the Aband saccharide ...

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“…Hence, at physiological pH both PL3 and PL5 of Wzy Sf possess net negative charge. While the P. aeruginosa PAO1 Oag contains negatively charged uronic acid (Knirel et al, 2006), S. flexneri Oag is neutral. So, the charge property of the substrate for Wzy Sf is different from that of Wzy Pa .…”

Section: Discussionmentioning

confidence: 99%