![]() Peptides belonging to the brevinin-1, brevinin-2, esculentin-1, and esculentin-2 families, previously isolated from the skins of Asian and European Ranid frogs, were not identified in the extract. In addition, five structurally related peptides (temporin-1Ca, -1Cb, -1Cc, -1Cd, and -1Ce), comprising 13 amino acid residues and containing a C-terminally alpha-amidated residue, belong to the temporin family first identified in the European common frog Rana temporaria. Ranatuerin-1C (SMLSVLKNLGKVGLGLVACKINKQC), ranalexin-1Ca (FLGGLMKAFPALICAVTKKC), ranalexin-1Cb (FLGGLMKAFPAIICAVTKKC), ranatuerin-2Ca (GLFLDTLKGAAKDVAGKLLEGLKCKIAGC KP), and ranatuerin-2Cb (GLFLDTLKGLAGKLLQGLKCIKAGCKP), are members of three previously characterized families of antimicrobial peptides, first identified in the North American bullfrog Rana catesbeiana. Ten peptides with differential growth-inhibitory activity against the gram-positive bacterium, Staphylococcus aureus, the gram-negative bacterium, Escherichia coli, and the yeast Candida albicans were isolated from an extract of the skin of a North American frog, the green frog Rana clamitans. Despite the close phylogenetic relationship between the various species of Ranid frogs, the distribution and amino-acid sequences of the antimicrobial peptides produced by each species are highly variable and species-specific, suggesting that they may be valuable in taxonomic classification and molecular phylogenetic analysis. Peptides belonging to the brevinin-2, ranalexin, esculentin-1 and ranatuerin-1 families were not identified in the extracts. Structural characterization of the antimicrobial peptides demonstrated that they belonged to four of the known families: the brevinin-1 family, first identified in skin of the Asian frog Rana porosa brevipoda the esculentin-2 family, first identified in the European frog Rana esculenta the ranatuerin-2 family, first identified in the North American bullfrog Rana catesbeiana and the temporin family, first identified in the European frog Rana temporaria. A total of 24 peptides with differential growth-inhibitory activity towards the Gram-positive bacterium Staphylococcus aureus, the Gram-negative bacterium Escherichia coli and the yeast Candida albicans were isolated from extracts of the skins of three closely related North American frogs, Rana luteiventris (spotted frog), Rana berlandieri (Rio Grande leopard frog) and Rana pipiens (Northern leopard frog). The skins of frogs of the genus Rana synthesize a complex array of antimicrobial peptides that may be grouped into eight families on the basis of structural similarity. The low hemolytic effect and wide-spectrum antimicrobial activity suggest a possible therapeutic application of these novel peptides. ![]() MIC values of these peptides are suitable for potent antimicrobial peptides. Human red blood cells tolerated well exposure to temporin-Ra and temporin-Rb, which, at a concentration of 60 µg/ml, induced 1.3% and 1.1% hemolysis, respectively. The molecular masses were found to be 1242.5 Da for temporin-Rb and 1585.1 Da for temporin-Ra. The sequences and molecular weights of these peptides were determined using tandem MS. Our results show that these peptides have inhibitory effects on both gram-negative and gram-positive bacteria, especially antibiotic resistant strains prevalent in hospitals, such as Staphylococcus aureus and Streptococcus agalactiae. Temporin-Ra and temporin-Rb are composed of 14 and 12 amino acids, respectively. In this study, two novel antimicrobial peptides from the skin secretions of the marsh frog, Rana ridibunda, named temporin-Ra and temporin-Rb, were identified and purified using RP-HPLC. Label proteins with click chemistry reactions and unnatural amino acid reactions.Quality Control and Quality Assurance of GMP.N-terminal Amino Acid Sequence Analysis.Mass Spectrometric Identification of Amino Acids.Direct Analysis of Underivatized Amino Acids.C-terminal Amino Acid Sequence Analysis.Crystallization Resolution of Amino Acids.Chromatographic Resolution of Amino acids.Capillary Electrophoresis Resolution of Amino Acids.Protection and Deprotection of Amino Acids.Protonation and Deprotonation of Amino Acids.PNA for OLED Application TM (PNA OLED TM).
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