Peptides as toxins/defensins

Profiling the peptidome of the venom from the social wasp Agelaia pallipes pallipes

“…The molecular mass of the natural peptide (598.42 Da) seems to be consistent with the C-terminal residue in the amidated form; thus, two peptides were synthesized with either Ile or Leu residue amidated at this position, and the retention times were measured both for the synthetic peptides and for the natural one using RP-HPLC (C18) ( (Table 1). This fraction was named Protonectin (7)(8)(9)(10)(11)(12) because it has the same amino acid sequence found in positions 7 to 12 of the peptide Protonectin [28]. This peptide presented no hemolytic and mast cell degranulation activities, but presented weak chemotactic activity (ED 50 =1×10 − 3 M) ( Table 2).…”

“…The results above are showing that the experimental strategy adopted in the present investigation permitted the unambigous sequencing of nine peptides (Table 1). Protonectin (1-4)-OH, Protonectin (1-5)-OH, Protonectin (1-6)-OH and Protonectin (7)(8)(9)(10)(11)(12), appear to be structurally related to the peptide Protonectin (despite the use of a cocktail of proteinases inhibitors), a dodecapeptide peptide previously reported in the venoms of the social wasps Protonectarina sylveirae [28] and A. p. pallipes [30]. Curiously, this peptide was not found in the current investigation; these results are suggesting that the Protonectin-like short peptides are not resulting from artifacts of sample manipulation, but may be natural products of proteases action on Protonectin as substrate.…”

“…It is widely recognized that many components are products of biochemical and pharmacological convergence during evolution, which resulted in very potent and selective compounds active against specific receptors [8,10]. The discovery of such natural toxins may lead to the identification of model compounds for the development of novel therapeutic agents [11,12].…”

“…These peptides may have pharmacological actions such as mast cell degranulation, chemotaxis of polymorphonuclear leukocytes (PMNL), cytolysis and smooth muscle contraction [7,8]. The identification of the peptides in venoms is important to characterize the pharmacological symptoms observed during the envenoming process.…”

Chemometric analysis of Hymenoptera toxins and defensins: A model for predicting the biological activity of novel peptides from venoms and hemolymph

“…Peptides may be constituents of larger proteins, in which case they are responsible for molecular recognition and biological activities, or they may be biosynthesized for important roles in many physiological processes, acting as neurotransmitters, hormones, toxins, antibiotics, and defensins [43]. Peptides in general target a wide variety of protein receptors at the level of biological membranes and may interact with the phospholipids of the plasma/organelle membranes and/or with cytosolic proteins, which may regulate their activities.…”