Novel antimicrobial peptides from skin secretion of the European frog <i>Rana esculenta</i>

Simmaco, Maurizio; Mignogna, Giuseppina; Barra, Donatella; Bossa, Francesco

doi:10.1016/0014-5793(93)81384-c

Cited by 155 publications

(146 citation statements)

References 17 publications

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“…This particular DPC/SDS molar ratio was chosen to be close to that between zwitterionic and negatively charged lipids typical for the inner membrane of Gram-negative bacteria. 25 Table S1 reports the 1 H and 13 C resonance assignments for Esc (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18) in the presence of either DPC or DPC/SDS micelles, obtained through a set of two-dimensional homo-and heteronuclear experiments, namely, DQF-COSY, TOCSY, NOESY, and HSQC. Figures 1a and 1b show the deviations of the observed chemical shifts from the reference "random coil" values for 1 H and 13 C, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…This is extremely important in order to improve peptide efficacy and selectivity through rational drug design. 14 Esculentin-1b is the most active peptide (among four families) extracted from the granular glands of the skin of the frog Rana esculenta, [15][16][17] more recently classified as Pelophylax lessonae/ridibundus. 18 Previous studies demonstrated that its outstanding antimicrobial activity is mostly due to the N-terminal fragment comprising the first 18 amino acid residues, Esc(1-18):…”

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confidence: 99%

“…17,19,20 Biological investigations demonstrated broad spectrum antimicrobial activity against different fungal and bacterial species, especially Gramnegative strains, including multidrug-resistant clinical isolates, while effects on erythrocytes were negligible. 17,20,21 Remarkably, it displayed comparable activity in the presence of human serum, differently from most of the known AMPs.…”

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confidence: 99%

“…23 A globally amphipathic structure was found, with a helical conformation for the N-terminal portion (encompassing the first 12 residues) and an unfolded C-terminal fragment. 23 However, as the H 2 O/TFE solvent is an isotropic environment, such a structural model for Esc (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18) should be taken with caution. Despite promoting peptide folding by favoring intramolecular H-bonds, indeed, H 2 O/TFE mixtures inherently lack the intrinsic anisotropic character of a lipid bilayer.…”

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confidence: 99%

“…In particular, both zwitterionic and negatively charged micelles have been employed to model eukaryotic and prokaryotic plasma membrane, respectively, as bacterial membranes are usually characterized by a higher content of negatively charged lipids than the former. 6,12,13 The insertion depth of Esc (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18) into the micelles was estimated by using Mn 2+ ions as a paramagnetic probe. The results clearly confirm the helical folding of Esc (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18) and show how binding and folding are prominent only in the presence of a negatively charged membrane.…”

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confidence: 99%

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Folded Structure and Insertion Depth of the Frog-Skin Antimicrobial Peptide Esculentin-1b(1–18) in the Presence of Differently Charged Membrane-Mimicking Micelles

Manzo¹,

Casu²,

Rinaldi³

et al. 2014

J. Nat. Prod.

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Antimicrobial peptides (AMPs) are effectors of the innate immunity of most organisms. Their role in the defense against pathogen attack and their high selectivity for bacterial cells make them attractive for the development of a new class of antimicrobial drugs. The N-terminal fragment of the frog-skin peptide esculentin-1b (Esc(1-18)) has shown broad spectrum antimicrobial activity.Similarly to most cationic AMPs, it is supposed to act by binding to and damaging the negatively charged plasma-membrane of bacteria. Differently from many other AMPs, Esc(1-18) activity is preserved in biological fluids such as serum. In this work, a structural investigation was performed through NMR spectroscopy. The 3D structure was obtained in the presence of either zwitterionic or negatively charged micelles as membrane models for eukaryotic and prokaryotic membranes, respectively. Esc(1-18) showed a higher affinity for and deeper insertion into the latter, and adopted an amphipathic helical structure characterized by a kink at the residue G8. These findings were confirmed by measuring penetration into lipid monolayers. The presence of negatively charged lipids in the bilayer appears to be necessary for Esc(1-18) to bind, fold in the right threedimensional structure and, ultimately, to exert its biological role as an AMP. 3The lack of a new class of antibiotics is an urgent problem, as many important pathogens are rapidly developing resistance to most of the clinically usable antibiotics. 1,2 Clinical impact of antibiotic resistance is immense, with increasing length of hospital stay, costs and mortality. 3,4 Antimicrobial peptides (AMPs) have attracted the interest of the scientific community as promising candidates for the development of a new class of antimicrobial drugs. They are part of the innate immune system of the majority of the multicellular organisms, and are typically characterized by a wide spectrum of antimicrobial activity, from Gram-negative to Gram-positive bacteria, fungi, protozoa and enveloped viruses. [5][6][7] Despite amino acid sequence homology is not high, AMPs share some common features. They are relatively short (< 60 residues), cationic, have a large content (≥ 50%) of hydrophobic residues and adopt an amphipathic three-dimensional folding when interacting with pathogens" membranes. 6 Generally, AMPs destroy or permeate the microbial plasma-membrane. The membrane is formed through evolutionarily well conserved biosynthetic processes and represents a non-selective target, making modifications by the microorganisms difficult and, thus, resistance onset is unlikely. 8 Several recent articles have reviewed in detail the different modes of action postulated for AMPs. [9][10][11] The amphipathic conformation adopted by the AMP, with the hydrophilic residues interacting with the polar head groups of the phospholipids and the water molecules, and the hydrophobic residues being protected from water contacts by inserting into the lipid bilayer core, is considered essential for it to exert the antimicro...

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