title: Synergistically acting PLA₂: peptide hemorrhagic complex from Daboia russelii venom.
abstract: Snake venoms are complex mixture of enzymatic and non-enzymatic proteins. Non-covalent protein-protein interaction leads to protein complexes, which bring about enhanced pharmacological injuries by their synergistic action. Here we report identification and characterization of a new Daboia russelii hemorrhagic complex I (DR-HC-I) containing phospholipase A₂ (PLA₂) and non-enzymatic peptide. DR-HC-I was isolated from the venom of D. russelii by CM-Shepadex-C25 and gel permeation chromatography. Individual components were purified and identified by RP-HPL chromatography, mass spectrometry and N-terminal amino acid sequencing. DR-HC-I complex was lethal to mice with the LD₅₀ dose of 0.7 mg/kg body weight with hemorrhagic and neurotoxic properties. DR-HC-I complex consists of non-hemorrhagic PLA₂ and neurotoxic non-enzymatic peptide. The non-enzymatic peptide quenched the intrinsic fluorescence of PLA₂ in a dose dependent manner, signifying the synergistic interaction between two proteins. PLA₂ and peptide toxin in a 5:2 M ratio induced skin hemorrhage in mice with MHD 20 μg. However, addition of ANS (1-Anilino-8-naphthalene sulfonate) to DR-HC-I complex inhibited skin hemorrhagic effect and also synergic interaction. But there was no impact on PLA₂ due to this synergistic interaction, and indirect hemolytic or plasma re-calcification activity. However, the synergistic interaction of PLA₂ and non-enzymatic peptide contributes to the enhanced venom-induced hemorrhage and toxicity of Daboia russellii venom.
authors.affiliation: Department of Studies in Biochemistry, Manasagangotri, University of Mysore, Mysore 570006, Karnataka, India.
authors.forename: Madhukumar
authors.initials: M
authors.lastname: Venkatesh
authors.forename: Veerabasappa
authors.initials: V
authors.lastname: Gowda
mesh_terms: D000595:Amino Acid Sequence; D000817:Anilino Naphthalenesulfonates / Q000378:metabolism; D000818:Animals; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D005453:Fluorescence; D006470:Hemorrhage / Q000139:chemically induced* / Q000188:drug therapy; D007928:Lethal Dose 50; D013058:Mass Spectrometry; D051379:Mice; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes / Q000378:metabolism* / Q000633:toxicity; D010455:Peptides / Q000378:metabolism / Q000494:pharmacology; D054467:Phospholipases A2 / Q000378:metabolism*; D017840:Daboia / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D012871:Skin Diseases / Q000139:chemically induced* / Q000188:drug therapy; D014757:Viper Venoms / Q000201:enzymology* / Q000633:toxicity
chemical_list: D000817:Anilino Naphthalenesulfonates; D046912:Multiprotein Complexes; D010455:Peptides; D014757:Viper Venoms; C027132:1-anilino-8-naphthalenesulfonate; D054467:Phospholipases A2
keywords: Daboia russelii; Hemorrhagic complex; Neurotoxin; Phospholipase A(2); Russell's viper; Snake venom