Macromolecular Crowding at Membrane Interfaces: Adsorption and Alignment of Membrane Peptides

Aisenbrey, Christopher; Bechinger, Burkhard; Gröbner, Gerhard

doi:10.1016/j.jmb.2007.10.053

Cited by 54 publications

(74 citation statements)

References 36 publications

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“…This data indicates that a reduced pH inhibits the antibacterial effects of LL-37 and may, therefore, impair host defense mechanisms. These results are consistent with findings by Bechinger (1996) and Aisenbrey et al (2008) 17,18 who revealed that at alkaline pH, LL-37 has a lower positive charge and thus is inserted more quickly into the bacterial membrane. More recent studies indicate that LL-37 has a broad antimicrobial spectrum against S. aureus and P. aeruginosa at neutral pH, while its antibacterial activity is inhibited at low pH conditions.…”

Section: Discussionsupporting

confidence: 93%

Evaluation of the antibacterial activity of human cathelicidin peptide-LL-37 in the presence of acidified nitrite

Hanna¹

2017

ZJMS

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Human cathelicidin antimicrobial peptide LL-37 and acidified nitrite are important components of the innate immune system that partake in preventing infections. Cathelicidin peptide LL-37 can be produced by epithelial tissues as well as by macrophages after microbial infections. This study was carried out to evaluate the antibacterial activity of LL-37 and acidified nitrite (AN) both individually and combined for their effect against the standard the strains of E.coli ATCC 25922 and S. aureus ATCC 25923. Methods: Flat-bottom micro well plates (96 wells) were used for the determination of bacteriostatic activity. Sodium nitrite (NaNO 2 ) and ascorbic acid (AA) were used to produce acidified nitrite (AN). The singular and combined forms of the antibacterial agents were used for evaluating the antibacterial activities of LL-37 through estimation optical density values at 480nm (OD 480nm ). Results: The LL-37 peptide showed antibacterial activity against E.coli ATCC 25922 and S. aureus ATCC 25923. The antibacterial efficacy was enhanced when the peptide was tested in combination with AN (P <0.001). In contrast, the combination of LL-37 with NaNO2 and AA has an antagonistic effect (P <0.001) on its antimicrobial properties. Conclusion:The combination of LL-37 with AN has a synergistic on the peptide's antimicrobial effect. Therefore, LL-37 which might show little antibacterial activity when used alone can provide protection when used in combination therapy with other antimicrobial agents.

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Section: Discussionsupporting

confidence: 93%

Evaluation of the antibacterial activity of human cathelicidin peptide-LL-37 in the presence of acidified nitrite

Hanna¹

2017

ZJMS

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“…The cationic peptides insert into and disrupt the bacterial plasma membrane (59,60). Insight into how a more alkaline pH might increase activity comes from NMR experiments with synthetic, histidine-rich peptides and lipid bilayers (61,62). Those studies indicate that the peptide assumes a position parallel to the lipid bilayer, weakening the membrane before insertion and then inserting and disrupting the membrane.…”

Section: Discussionmentioning

confidence: 99%

pH modulates the activity and synergism of the airway surface liquid antimicrobials β-defensin-3 and LL-37

Alaiwa¹,

Reznikov²,

Gansemer³

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

181

162

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The pulmonary airways are continuously exposed to bacteria. As a first line of defense against infection, the airway surface liquid (ASL) contains a complex mixture of antimicrobial factors that kill inhaled and aspirated bacteria. The composition of ASL is critical for antimicrobial effectiveness. For example, in cystic fibrosis an abnormally acidic ASL inhibits antimicrobial activity. Here, we tested the effect of pH on the activity of an ASL defensin, human β-defensin-3 (hBD-3), and the cathelicidin-related peptide, LL-37. We found that reducing pH from 8.0 to 6.8 reduced the ability of both peptides to kill Staphylococcus aureus. An acidic pH also attenuated LL-37 killing of Pseudomonas aeruginosa. In addition, we discovered synergism between hBD-3 and LL-37 in killing S. aureus. LL-37 and lysozyme were also synergistic. Importantly, an acidic pH reduced the synergistic effects of combinations of ASL antibacterials. These results indicate that an acidic pH reduces the activity of individual ASL antimicrobials, impairs synergism between them, and thus may disrupt an important airway host defense mechanism.

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“…5A) is influenced both by the spatial constraints of the receptor and by the receptor-surface contact time. The adhesion drop at ligand densities Ͼ10 mol % Man 9 GlcNAc 2 -DPPE is probably due to ligand crowding, which would sterically impede ligand interactions with the CRDs (25)(26)(27)(28).…”

Section: Importance Of Ligand Density and Mobility For Engagement Of mentioning

confidence: 99%

Binding-site geometry and flexibility in DC-SIGN demonstrated with surface force measurements

Menon¹,

Rosenberg

Graham

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

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The dendritic cell receptor DC-SIGN mediates pathogen recognition by binding to glycans characteristic of pathogen surfaces, including those found on HIV. Clustering of carbohydrate-binding sites in the receptor tetramer is believed to be critical for targeting of pathogen glycans, but the arrangement of these sites remains poorly understood. Surface force measurements between apposed lipid bilayers displaying the extracellular domain of DC-SIGN and a neoglycolipid bearing an oligosaccharide ligand provide evidence that the receptor is in an extended conformation and that glycan docking is associated with a conformational change that repositions the carbohydrate-recognition domains during ligand binding. The results further show that the lateral mobility of membranebound ligands enhances the engagement of multiple carbohydrate-recognition domains in the receptor oligomer with appropriately spaced ligands. These studies highlight differences between pathogen targeting by DC-SIGN and receptors in which binding sites at fixed spacing bind to simple molecular patterns.adhesion ͉ molecular recognition ͉ pathogen selectivity ͉ multivalent receptors

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Macromolecular Crowding at Membrane Interfaces: Adsorption and Alignment of Membrane Peptides

Cited by 54 publications

References 36 publications

Evaluation of the antibacterial activity of human cathelicidin peptide-LL-37 in the presence of acidified nitrite

Evaluation of the antibacterial activity of human cathelicidin peptide-LL-37 in the presence of acidified nitrite

pH modulates the activity and synergism of the airway surface liquid antimicrobials β-defensin-3 and LL-37

Binding-site geometry and flexibility in DC-SIGN demonstrated with surface force measurements

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