HYL-20 (GILSSLWKKLKKIIAK-NH2) is an analogue of a natural antimicrobial peptide (AMP) previously isolated from the venom of wild bee. We examined its antimicrobial activity against three strains of Enterococcus faecalis while focusing on its susceptibility to proteolytic degradation by two known proteases-gelatinase (GelE) and serine protease (SprE)-which are secreted by these bacterial strains. We found that HYL-20 was primarily deamidated at its C-terminal which made the peptide susceptible to consecutive intramolecular cleavage by GelE. Further study utilising 1,10-phenanthroline, a specific GelE inhibitor and analogous peptide with D-Lys at its C-terminus (HYL-20k) revealed that the C-terminal deamidation of HYL-20 is attributed to not yet unidentified protease which also cleaves internal peptide bonds of AMPs. In contrast to published data, participation of SprE in the protective mechanism of E. faecalis against AMPs was not proved. The resistance of HYL-20k to C-terminal deamidation and subsequent intramolecular cleavage has resulted in increased antimicrobial activity against E. faecalis grown in planktonic and biofilm form when compared to HYL-20.

• MeSH
• Anti-Bacterial Agents chemical synthesis   metabolism   pharmacology   MeSH
• Bacterial Proteins antagonists & inhibitors   chemistry   metabolism   MeSH
• Biofilms drug effects   growth & development   MeSH
• Enterococcus faecalis drug effects   enzymology   growth & development   ultrastructure   MeSH
• Phenanthrolines pharmacology   MeSH
• Enzyme Inhibitors pharmacology   MeSH
• Antimicrobial Cationic Peptides chemical synthesis   metabolism   pharmacology   MeSH
• Microbial Sensitivity Tests MeSH
• Plankton drug effects   enzymology   growth & development   ultrastructure   MeSH
• Proteolysis MeSH
• Amino Acid Sequence MeSH
• Serine Endopeptidases chemistry   metabolism   MeSH
• Amino Acid Substitution MeSH
• Bees chemistry   physiology   MeSH
• Structure-Activity Relationship MeSH
• Gelatinases antagonists & inhibitors   chemistry   metabolism   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH

Four new peptides of the mastoparan family, characterized recently in the venom of three neotropical social wasps collected in the Dominican Republic, Polistes major major, Polistes dorsalis dorsalis and Mischocyttarus phthisicus were synthesized and tested for antimicrobial potency against Bacillus subtilis, Staphylococcus aureus, Escherichia coli (E.c.) and Pseudomonas aeruginosa, and for hemolytic and mast cells degranulation activities. As these peptides possess strong antimicrobial activity (minimal inhibitory concentration (MIC) values against Bacillus subtillis and E.c. in the range of 5-40 microM), we prepared 40 of their analogs to correlate biological activities, especially antimicrobial, with the net positive charge, hydrophobicity, amphipathicity, peptide length, amino acid substitutions at different positions of the peptide chain, N-terminal acylation and C-terminal deamidation. Circular dichroism spectra of the peptides measured in the presence of trifluoroethanol or SDS showed that the peptides might adopt alpha-helical conformation in such anisotropic environments.

• MeSH
• Anti-Bacterial Agents pharmacology   chemical synthesis   chemistry   MeSH
• Bacillus subtilis drug effects   MeSH
• Cell Degranulation MeSH
• Erythrocytes drug effects   MeSH
• Escherichia coli drug effects   MeSH
• Financing, Organized MeSH
• Hemolysis physiology   drug effects   MeSH
• Hydrophobic and Hydrophilic Interactions MeSH
• Inhibitory Concentration 50 MeSH
• Antimicrobial Cationic Peptides pharmacology   chemical synthesis   chemistry   MeSH
• Rats MeSH
• Mast Cells physiology   drug effects   MeSH
• Microbial Sensitivity Tests MeSH
• Molecular Sequence Data MeSH
• Peptides pharmacology   chemical synthesis   chemistry   isolation & purification   drug effects   MeSH
• Pseudomonas aeruginosa drug effects   MeSH
• Amino Acid Sequence MeSH
• Wasps chemistry   MeSH
• Staphylococcus aureus drug effects   MeSH
• Amino Acid Substitution MeSH
• Wasp Venoms pharmacology   genetics   chemistry   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Animals MeSH

Three novel structurally related pentadecapeptides, named lasioglossins, were isolated from the venom of the eusocial bee Lasioglossum laticeps. Their primary sequences were established as H-Val-Asn-Trp-Lys-Lys-Val-Leu-Gly-Lys-Ile-Ile-Lys-Val-Ala-Lys-NH(2) (LL-I), H-Val-Asn-Trp-Lys-Lys-Ile-Leu-Gly-Lys-Ile-Ile-Lys-Val-Ala-Lys-NH(2) (LL-II) and H-Val-Asn-Trp-Lys-Lys-Ile-Leu-Gly-Lys-Ile-Ile-Lys-Val-Val-Lys-NH(2) (LL-III). These lasioglossins exhibited potent antimicrobial activity against both Gram-positive and Gram-negative bacteria, low haemolytic and mast cell degranulation activity, and a potency to kill various cancer cells in vitro. The lasioglossin CD spectra were measured in the presence of trifluoroethanol and sodium dodecyl sulfate solution and indicated a high degree of alpha-helical conformation. NMR spectroscopy, which was carried out in trifluoroethanol/water confirmed a curved alpha-helical conformation with a concave hydrophobic and convex hydrophilic side. To understand the role of this bend on biological activity, we studied lasioglossin analogues in which the Gly in the centre of the molecule was replaced by other amino acid residues (Ala, Lys, Pro). The importance of the N-terminal part of the molecule to the antimicrobial activity was revealed through truncation of five residues from both the N and C termini of the LL-III peptide. C-terminal deamidation of LL-III resulted in a drop in antimicrobial activity, but esterification of the C terminus had no effect. Molecular modelling of LL-III and the observed NOE contacts indicated the possible formation of a bifurcated H-bond between hydrogen from the Lys15 CONH peptide bond and one H of the C-terminal CONH(2) to the Ile11 oxygen atom. Such interactions cannot form with C-terminal esterification.

• MeSH
• Anti-Infective Agents pharmacology   chemical synthesis   chemistry   MeSH
• Gram-Negative Bacteria drug effects   MeSH
• Gram-Positive Bacteria drug effects   MeSH
• Hemolysis drug effects   MeSH
• Antimicrobial Cationic Peptides pharmacology   chemistry   MeSH
• Humans MeSH
• Magnetic Resonance Spectroscopy MeSH
• Mast Cells metabolism   drug effects   MeSH
• Microbial Sensitivity Tests MeSH
• Cell Line, Tumor MeSH
• Peptides pharmacology   chemical synthesis   chemistry   MeSH
• Cell Proliferation drug effects   MeSH
• Antineoplastic Agents pharmacology   chemical synthesis   chemistry   MeSH
• Drug Screening Assays, Antitumor MeSH
• Bee Venoms chemistry   MeSH
• Bees chemistry   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Research Support, Non-U.S. Gov't MeSH