AI Article Synopsis

  • The proteomic analysis of Micrurus browni browni venom identified around 41 components from 9 protein families, primarily phospholipases A (PLAs) and three-finger toxins (3FTxs).
  • The study discovered a complex toxin, named Brownitoxin-1, which shows low lethality in its individual components but becomes highly toxic when combined, along with identifying other lethal toxins like a neurotoxic PLA and an α-neurotoxin.
  • This research provides extensive characterization of coral snake venom, emphasizing the role of protein complexes in venom functionality and enhancing the understanding of North American coral snake venoms, which are not well studied.

Article Abstract

Proteomic characterization of Micrurus browni browni venom showed approximately 41 components belonging to 9 protein families, mainly phospholipases A (PLAs) and three-finger toxins (3FTxs). Venom gland transcriptome yielded 39 venom transcripts belonging to 10 protein families. Functional characterization identified a multimeric toxin, here designated Brownitoxin-1, which comprises at least one PLA and one 3FTx. Its components have no or very low lethality individually but become extremely lethal when combined; both were partially characterized. Other two lethal components were identified: A neurotoxic PLA, and a postsynaptic α-neurotoxin. LDs as well as PLA and nAChR-blocking activities were determined for whole venom and isolated components. Application of venom to murine neuromuscular preparations caused a progressive decrease of twitch force that was irreversible after washing. Inhibition of PLA activity with p-bromophenacyl bromide (pBPB) showed that approximately 90% of toxicity is dependent on this activity. Non-lethal components include diverse 3FTxs, at least three enzymatically active PLAs and the nociceptive toxin MitTx. No evidence of specificity towards prey was observed. This work is one of the most complete characterizations of a coral snake venom so far and its findings highlight the relevance of protein complexes in venom function. SIGNIFICANCE: This study represents a profound analysis of the venom of the coral snake Micrurus browni browni, including a venom proteome, venom gland transcriptomic data and functional studies of whole venom and isolated toxins. It significantly contributes to the understanding of North American coral snake venoms, which are currently largely unknown. It includes characterization of relevant venom components, one of which represents the first description of a lethal multimeric neurotoxin in coral snake venom. This work highlights the importance of protein complexes in coral snake venom and could serve as a basis for the finding of several other multimeric toxins. Finally, we report the absence of taxon specificity, which has been previously reported in the venoms of other snakes of the same genus.

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Source
http://dx.doi.org/10.1016/j.jprot.2020.103863DOI Listing

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