title: Structural identification by mass spectrometry of a novel antimicrobial peptide from the venom of the solitary bee Osmia rufa (Hymenoptera: Megachilidae).
abstract: The venom from the solitary bee Osmia rufa (Hymenoptera: Megachilidae) was analyzed using mass spectrometry (MS)-based techniques. Sensitive proteomic methods such as on-line LC-ESI-MS and nanoESI-MS analyses revealed more than 50 different compounds with molecular masses ranging from 400 to 4000Da. The major component has a monoisotopic molecular mass of 1924.20Da and its amino acid sequence was elucidated by de novo sequencing using tandem mass spectrometry and Edman degradation. This 17-residue cysteine-free peptide, named osmin, shows some similarities with the mast cell degranulation (MCD) peptide family. Free acid and C-terminally amidated osmins were chemically synthesized and tested for antimicrobial and haemolytic activities. The synthetic C-amidated peptide (native osmin) was found to be about three times more haemolytic than its free acid counterpart, but both peptides are much less lytic than melittin from social bee venom. Preliminary antimicrobial and antifungal tests indicate that both peptides are able to inhibit bacterial and fungal growth at micromolar concentrations.
authors.affiliation: Atheris Laboratories, Case postale 314, CH-1233 Bernex-Geneva, Switzerland. reto.stocklin@atheris.ch
authors.forename: Reto
authors.initials: R
authors.lastname: Stöcklin
authors.forename: Philippe
authors.initials: P
authors.lastname: Favreau
authors.forename: Robert
authors.initials: R
authors.lastname: Thai
authors.forename: Jochen
authors.initials: J
authors.lastname: Pflugfelder
authors.forename: Philippe
authors.initials: P
authors.lastname: Bulet
authors.forename: Dietrich
authors.initials: D
authors.lastname: Mebs
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000890:Anti-Infective Agents / Q000138:chemical synthesis / Q000737:chemistry*; D000935:Antifungal Agents / Q000138:chemical synthesis / Q000737:chemistry*; D023181:Antimicrobial Cationic Peptides / Q000138:chemical synthesis / Q000737:chemistry*; D001514:Bee Venoms / Q000138:chemical synthesis / Q000737:chemistry* / Q000302:isolation & purification; D001516:Bees / Q000033:anatomy & histology / Q000737:chemistry* / Q000648:ultrastructure; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D005658:Fungi / Q000187:drug effects; D006090:Gram-Negative Bacteria / Q000187:drug effects; D006094:Gram-Positive Bacteria / Q000187:drug effects; D006461:Hemolysis / Q000187:drug effects; D019476:Insect Proteins / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry*; D016415:Sequence Alignment; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D000890:Anti-Infective Agents; D000935:Antifungal Agents; D023181:Antimicrobial Cationic Peptides; D001514:Bee Venoms; D019476:Insect Proteins; D010455:Peptides; C547752:osmin protein, Osmia rufa