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A new class of compounds, acylpolyamine has been isolated from spider venom constituents. Recent advances in highly sensitive mass spectrometric techniques have been applied successfully to characterize these acylpolyamines even with the use of a single venom gland. This has been achieved, in part, by improvements in fast atom bombardment mass spectrometry (FAB), continuous flow (FRIT) FAB-MS combined with reversed-phase high performance liquid chromatography (HPLC), matrix assisted laser desorption/ionization (MALDI) and high energy collision induced dissociation (CID) tandem MS/MS. Crude venom analysis without chromatographic separation can be realized directly by MALDI-MS. A charge-remote fragmentation method has provided abundant structure-related product ions and have reduced the quantity of required venom for the structure analysis of acylpolyamines. These mass spectrometric methods were proved to be useful for the analysis of complex constituents of spiders and other arthropod venom glands. [ABSTRACT FROM AUTHOR]

Four peptidyl inhibitors of the small-conductance Ca2+-activated K+ channels (SKca) have been isolated from the venom of the Chinese scorpion Buthus martensi. These peptides were identified by screening C18 HPLC fractions of the crude venom by means of mass analysis by matrix-assisted-laser-desorption/ionization time-of-flight mass spectrometry, and toxicological tests in mice. Edman degradation analysis of the purified peptides showed sequences of 28–31 amino acids including 6 cysteine residues. Three of the sequences were similar to the P01 peptides from Androctonus scorpions, showing 76% sequence similarity for the most closely related, named BmP01. and 46% for the other two, named BmP02 and BmP03. Like the P01 peptides, these molecules showed a low toxic activity in mice after intracerebro-ventricular injection, and competed (K0.5 > 1 μM) with iodinated apamin for binding to its receptor site from rat brain, which has been proved to be the SKca channels. The fourth toxin was structurally related to the P05/leiurotixin I toxin family, with 90% similarity, and was named BmP05. This toxin exhibited a high toxic activity with lethal effects in mice. Due to its small representation in the venom [less than 0.01% (by mass)], its biological properties have been assessed on the synthetic analogue of BmP05. which was assembled on a solid phase by means of Fmoc methodology. The synthetic peptide was physicochemically identical to the natural peptide, as shown by comparison of their molecular masses and amino acid compositions, and by their coelution after coinjection on capillary electrophoresis. These results confirmed the primary structure of BmP05 including an amidated C-terminus. Similarly to natural BmP05, synthetic BmP05 produced toxic and lethal effects after intracerebroventricular injection in mice (LD50 = 37 rig). and was able to compete with iodinated apamin for binding to its receptor in rat brain (K0.5 = 20 pM). [ABSTRACT FROM AUTHOR]

Abstract: A novel antimicrobial peptide, eumenitin, was isolated from the venom of the solitary eumenine wasp Eumenes rubronotatus. The sequence of eumenitin, Leu–Asn–Leu–Lys–Gly–Ile–Phe–Lys–Lys–Val–Ala–Ser–Leu–Leu–Thr, was mostly analyzed by mass spectrometry together with Edman degradation, and corroborated by solid-phase synthesis. This peptide has characteristic features of cationic linear α-helical antimicrobial peptides, and therefore, can be predicted to adopt an amphipathic α-helix secondary structure. In fact, the CD spectra of eumenitin in the presence of TFE or SDS showed a high content of α-helical conformation. Eumenitin exhibited inhibitory activity against both Gram-positive and Gram-negative bacteria, and moderately stimulated degranulation from the rat peritoneal mast cells and the RBL-2H3 cells, but showed no hemolytic activity against human erythrocytes. This antimicrobial peptide in the eumenine wasp venom may play a role in preventing potential infection by microorganisms during prey consumption by their larvae. [Copyright &y& Elsevier]