Interfacial properties and structural analysis of the antimicrobial peptide NK‐2

Olak, Claudia; Muenter, Annabel H.; Andrä, Jörg; Brezesinski, Gerald

doi:10.1002/psc.954

Cited by 24 publications

(36 citation statements)

References 38 publications

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“…Obviously, only the interactions with aggregated SDS lead to a change in the secondary structure from unstructured to ¡-helical. This effect has not been observed for other antimicrobial peptides, e.g., C/S-Ar-1 in our study, Ar-2, 20 ¡-helical porcine-derived NK-2, 18 or other CAP-derived peptides. 22 The reduced intensity of the spectrum can be the result of the shading of larger particles, 23 such as aggregates or vesicles.…”

Section: ¹1contrasting

confidence: 72%

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Effect of SDS and CTAB on Derivatives of Antimicrobial Peptides Arenicin and LL-37

2012

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The interaction of two antimicrobial peptides (AMPs) with amphiphiles was investigated. In addition, the influence of sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB) solutions, both below and above the critical micelle concentration (cmc), was investigated by circular dichroism (CD) spectroscopy. The AMPs we used were from two different classes: C/S-Ar-1, from a lugworm, and LL-20, a fragment of human LL-37. Cationic CTAB did not influence the AMPs, independent of the amphiphile aggregation state. However, anionic SDS had a clear effect on the secondary structure of the peptides. In the case of C/S-Ar-1, no difference was observed in the CD spectra below or above the cmc (change to ¢-sheet). In contrast, SDS monomers led to an aggregation of LL-20 and SDS micelles changed the secondary structure of the peptides from unstructured to ¡-helical.Antimicrobial peptides (AMPs) have become very attractive objects for investigations because of the rise in the number of problems with antibiotics.

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Section: ¹1contrasting

confidence: 72%

“…The maximum at 230 nm is due to the contribution of aromatic side chains. The CD spectrum for LL-20 in water (Figure 1) is a typical one for an unstructured peptide, 18,19 since it shows a pronounced minimum at 198 nm and a small negative shoulder around 230 nm.…”

Section: ¹1mentioning

confidence: 99%

Effect of SDS and CTAB on Derivatives of Antimicrobial Peptides Arenicin and LL-37

2012

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“…The addition of POPC vesicles to the peptide solution has only little effect on the peptide conformation. The CD spectra correspond still to an unstructured peptide [70,71], although the intensity at 230 nm is slightly increased. However, the addition of POPG vesicles leads to a drastic change in the peptide conformation of both LL-32 and LL-20.…”

Section: Comparison To Measurements In Bulkmentioning

confidence: 92%

Interactions of Two Fragments of the Human Antimicrobial Peptide LL-37 with Zwitterionic and Anionic Lipid Monolayers

Dannehl

Brezesinski

Möhwald

2014

Zeitschrift Für Physikalische Chemie

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The interactions of two fragments of the human antimicrobial LL-37 with lipid monolayers at the soft liquid/air interface have been characterized. To model the interaction with mammalian cell membranes, lipid monolayers composed of the zwitterionic DPPC and DOPC were used. To investigate the interaction with bacterial cell membranes, lipid monolayers of anionic DPPG and POPG were used. DPPC and DPPG exhibit a first-order phase transition from the disordered liquid to the ordered condensed state, whereas POPG and DOPC monolayers are in the fluid disordered state at all surface pressures studied. Therefore, the influence of the monolayer phase state on peptide-lipid interactions can be studied. To obtain insight into the peptide structure and their influence on phospholipid membranes, film balance measurements were coupled with surface sensitive Infrared Reflection-Absorption Spectroscopy (IRRAS). The results were compared to CD measurements in bulk. LL-32 is more surface active and can better intercalate into lipid monolayers than LL-20. Even though LL-32 has no cell-selectivity, our results show how the peptide interacts differently with zwitterionic compared to anionic membrane models. The interaction with DPPC monolayers is based on simple intercalation of the peptides between the lipid molecules. However, the peptides bind in a two-step process to DPPG monolayers, which results in a fluidization of the lipid film. This can be related to a membrane thinning.

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“…The same phenomenon of the effect of salt on the surface activity was independently observed for other antimicrobial peptides. [15][16][17] The decrease of the ionic strength of the 1 mm C/SAr-1 solution leads to the decrease of the equilibrium surface pressure from 9 to 5 mN m…”

Section: Adsorption To the Air-water Interfacementioning

confidence: 99%

Conformational Properties of Arenicins: From the Bulk to the Air–Water Interface

et al. 2010

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The structures of two antimicrobial peptides (arenicin Ar‐1 and its linear derivative C/S‐Ar‐1) are studied in different solutions and at the air–water interface using spectroscopic methods such as circular dichroism (CD) and infrared reflection absorption spectroscopy (IRRAS) as well as grazing incidence X‐ray diffraction (GIXD) and specular X‐ray reflectivity (XR). Both peptides exhibit similar structures in solution. In the buffer used for most of the experiments the main secondary structure elements are 22 % β‐turn, 38 % β‐sheet and 38 % random coil. The amphiphilic peptides are surface‐active and form a Gibbs monolayer at the air–buffer interface. The surface activity is drastically increased by increasing the ionic strength of the subphase. The β‐sheet layer is quite stable and can be compressed to higher surface pressures. This adsorption layer is very crystalline. Bragg peaks corresponding to an interstrand distance of 4.78 Å and to an end‐to‐end distance have been observed. This end‐to‐end distance can be connected with the observed differences in the layer thickness leading to the assumption that the peptides form a hairpin which is bended depending on the interactions with the counterions.

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Interfacial properties and structural analysis of the antimicrobial peptide NK‐2

Cited by 24 publications

References 38 publications

Effect of SDS and CTAB on Derivatives of Antimicrobial Peptides Arenicin and LL-37

Effect of SDS and CTAB on Derivatives of Antimicrobial Peptides Arenicin and LL-37

Interactions of Two Fragments of the Human Antimicrobial Peptide LL-37 with Zwitterionic and Anionic Lipid Monolayers

Conformational Properties of Arenicins: From the Bulk to the Air–Water Interface

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