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The increasing resistance of bacteria and fungi to currently available antibiotics is a major concern worldwide, leading to enormous efforts to develop new antibiotics with new modes of actions. Antibacterial peptide CM4 (ABP-CM4) is a small cationic peptide with broad-spectrum activities against bacteria, fungi, and tumor cells, which may possibly be used as a promising candidate for a new antibiotic. For pharmaceutical applications, a large quantity of antimicrobial peptides needs to be produced economically. In this communication, the progress in the structural characteristics, heterologous production, and biological evaluation of ABP-CM4 are reviewed. [ABSTRACT FROM AUTHOR]

Abstract: An antibacterial peptide was isolated from a lepidopteran insect, Spodoptera litura. The molecular mass of this peptide was determined to be 4489.55 by matrix assisted laser desorption/ionization-time of flight mass (MALDI-TOF MS) spectrometry. The peptide consists of 42 amino acids and the sequence has 69–98% identity to those of moricin-related peptides, antibacterial peptides from lepidopetran insects. Thus, the peptide was designated S. litura (Sl) moricin. Sl moricin showed a broad antibacterial spectrum against Gram-positive and negative bacteria. Sl moricin gene was inducible by bacterial injection and expressed tissue—specifically in the fat body and hemocytes. Furthermore, the solution structure of Sl moricin was determined by two-dimensional (2D) 1H-nuclear magnetic resonance (NMR) spectroscopy and hybrid distance geometry-simulated annealing calculation. The tertiary structure revealed a long α-helix containing eight turns along nearly the full length of the peptide like that of moricin, confirming that Sl moricin is a new moricin-like antibacterial peptide. These results suggest that moricin is present not only in B. mori but also in other lepidopteran insects forming a gene family. [Copyright &y& Elsevier]

Water-soluble extracts of 9 Italian cheese varieties that differed mainly for type of cheese milk, starter, technology, and time of ripening were fractionated by reversed-phase fast protein liquid chromatography, and the antimicrobial activity of each fraction was first assayed toward Lactobacillus sakei A15 by well-diffusion assay. Active fractions were further analyzed by HPLC coupled to electrospray ionization-ion trap mass spectrometry, and peptide sequences were identified by comparison with a proteomic database. Parmigiano Reggiano, Fossa, and Gorgonzola water-soluble extracts did not show antibacterial peptides. Fractions of Pecorino Romano, Canestrato Pugliese, Crescenza, and Caprino del Piemonte contained a mixture of peptides with a high degree of homology. Pasta filata cheeses (Caciocavallo and Mozzarella) also had antibacterial peptides. Peptides showed high levels of homology with N-terminal, C-terminal, or whole fragments of well known antimicrobial or multifunctional peptides reported in the literature: αS1-casokinin (e.g., sheep αS1-casein (CN) f22-30 of Pecorino Romano and cow αS1-CN f24-33 of Canestrato Pugliese); isracidin (e.g., sheep αS1-CN f10-21 of Pecorino Romano); kappacin and casoplatelin (e.g., cow κ-CN f106-115 of Canestrato Pugliese and Crescenza); and β-casomorphin-11 (e.g., goat β-CN f60-68 of Caprino del Piemonte). As shown by the broth microdilution technique, most of the water-soluble fractions had a large spectrum of inhibition (minimal inhibitory concentration of 20 to 200 µg/mL) toward gram-positive and gram-negative bacterial species, including potentially pathogenic bacteria of clinical interest. Cheeses manufactured from different types of cheese milk (cow, sheep, and goat) have the potential to generate similar peptides with antimicrobial activity. [ABSTRACT FROM AUTHOR]