Proteomic characterization and lethality of the venom of the Black Judean scorpion, Hottentotta judaicus (Buthidae): expanded toxin diversity and revisited toxicological significance.

Abstract

The scorpion Hottentotta judaicus inhabits the Levant region of the Middle East, including Lebanon, Jordan, Palestine, and Israel. While previous research focused on its insecticidal properties and sodium-channel-targeting toxins, its venom remains largely unexplored using modern proteomic approaches. We analyzed the venom composition of H. judaicus from Lebanese specimens using nESI-MS/MS, MALDI-TOF MS, SDS-PAGE, and RP-HPLC. Venom lethality in mice was assessed (LD₅₀ = 11.87 [6.59-17.16] mg/kg, i.p.), confirming moderate toxicity to vertebrates. RP-HPLC on C₁₈ resolved 37 peaks, with 25 eluting between 20-40% acetonitrile. Reducing SDS-PAGE revealed predominant components < 10 kDa and minor bands at 31, 46, and 77 kDa. MaLDI-TOF MS detected 20 components from 1,000-12,000 m/z. A bottom-up shotgun nLC-MS/MS approach, following in-gel tryptic digestion of venom, identified 55 components across 15 protein families. Ion channel-active toxins [K⁺ (7), Na⁺ (16), Cl⁻ (1), ryanodine receptor (1)] and enzyme components (17) were predominant. This study provides proteomic evidence of H. judaicus venom components previously only identified at the transcriptomic level and reveals a richer venom profile than anticipated. Novel identified components include alternative β-subunits of lipolysis-activating proteins, as well as homologs of Olivierus martensii antimicrobial peptide inhibitor HAP-1, Leiurus hebraeus Lqhβ1, Parabuthus transvaalicus Birtoxin, and peptide Hj2a from Hottentotta jayakari exhibiting dual α/β-toxin activity on Nav1.1 channels. This expanding repertoire of potential bioactive components prompts a reevaluation of the pathophysiological consequences of H. judaicus envenomation in humans and further exploration of their potential biomedical applications.