Moving pieces in a proteomic puzzle: mass fingerprinting of toxic fractions from the venom of Tityus serrulatus (Scorpiones, Buthidae)

Abstract

Scorpion venoms are very complex mixtures of molecules, most of which are peptides that display different kinds of biological activity. These venoms have been studied in the light of their pharmacological targets and their constituents are able to bind specifically to a variety of ionic channels located in prey tissues, resulting in neurotoxic effects. Toxins that modulate Na(+), K(+), Ca(++) and Cl(-) currents have been described in scorpion venoms. Mass spectrometry was employed to analyze toxic fractions from the venom of the Brazilian scorpion Tityus serrulatus in order to shed light on the molecular composition of this venom and to facilitate the search for novel pharmacologically active compounds. T. serrulatus venom was first subjected to gel filtration to separate its constituents according to their molecular size. The resultant fractions II and III, which account for 90 and 10% respectively of the whole venom toxic effect, were further analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS), on-line liquid chromatography/electrospray mass spectrometry (LC/ESMS) and off-line LC/MALDI-TOFMS in order to establish their mass fingerprints. The molecular masses in fraction II were predominantly between 6500 and 7500 Da. This corresponds to long-chain toxins that mainly act on voltage-gated Na(+) channels. Fraction III is more complex and predominantly contained molecules with masses between 2500 and 5000 Da. This corresponds to the short-chain toxin family, most of which act on K(+) channels, and other unknown peptides. Finally, we were able to measure the molecular masses of 380 different compounds present in the two fractions investigated. To our knowledge, this is the largest number of components ever detected in the venom of a single animal species. Some of the toxins described previously from T. serrulatus venom could be detected by virtue of their molecular masses. The interpretation of this large set of data has provided us with useful proteomic information on the venom, and the implications of these findings are discussed.

Unique diversity of the venom peptides from the scorpion Androctonus bicolor revealed by transcriptomic and proteomic analysis

“…AbNt8 is rich in charged residues, containing 19.7% negatively charged residues (D and E) and 20.9% positively charged residues (R, K and H). Based on the classification rule of NDBPs, AbNt8 was classified as the first member of a new subfamily of NDBPs, NDBP 12 .…”

“…Venomics studies using optimized liquid chromatography mass spectrometry (LC-MS) approaches revealed that each species of scorpions may contain approximately 100 different venom peptides [2,11,12]. It was estimated that approximately 200,000 different venom peptides exist in the venom glands of 2000 different species of scorpions.…”

“…The cysteine pattern of Androcin is the same with that of AbTxC 12 1. The transcripts of Androcin and AbTxC 12 1 account for 0.81% and 0.32% of the total venom peptide transcripts of A. bicolor, respectively.…”

Miniaturization of Scorpion β-Toxins Uncovers a Putative Ancestral Surface of Interaction with Voltage-gated Sodium Channels

“…Inactive fractions or substances are usually disregarded as they are not expected to yield a valuable end product. These basic considerations have led to the present situation where of 100 -300 distinct polypeptides that can be monitored by mass spectroscopy in the venom of a single scorpion or a spider, the biological activity of only a small portion has been characterized (4,38,39). However, there are numerous reasons to believe that compounds that at first glance seem inactive should not be ignored.…”

“…It is therefore rational to believe that when scorpion toxins that affect Na v s degrade either in the venom glands (39) or in the stung animal (hemolymph or blood), their partially degraded derivatives may "boost" the impact of the entire venom. This phenomenon also provides a conceptual basis to future attempts to decrease doses of drugs by harmless, allosterically acting compounds.…”