Molecular cloning and characterization of the two putative toxins expressed in the venom of the devil stinger Inimicus japonicus. (15th October 2021)

• Record Type: Journal Article
• Authors: Hatakeyama, Tomomitsu; Kishigawa, Akihiro; Unno, Hideaki
• Is Part Of: Toxicon. Volume 201(2021)
• Page Start: 9
• Page End: 20
• Publication Date: 2021-10-15
• Subjects: Inimicus japonicus -- Fish venom -- Natterin -- Next generation sequencing -- Phospholipase A2 -- Pore-forming protein; Toxins -- Periodicals; Venom -- Periodicals; 615.9
• DOI: 10.1016/j.toxicon.2021.08.006
• Languages: English
• ISSNs: 0041-0101

Abstract

Abstract: Various proteins are involved in fish venom toxicity, but limited information is available regarding their structure and mode of action. Here, we analyzed RNA transcripts in the dorsal spine of the devil stinger Inimicus japonicus using next-generation sequencing (NGS), and identified two putative protein toxins, a natterin-like protein (Ij-natterin) and a phospholipase A2 (Ij-PLA2 ), as well as a previously reported stonustoxin-like protein. The deduced amino acid sequence of Ij-natterin suggested that it acts as a pore-forming toxin through the cooperation of the N-terminal lectin-like domain and the C-terminal pore-forming domain. Ij-PLA2 showed significant homology with secreted Ca 2+ -dependent PLA2 s from snake venom and mammals (sPLA2 -I/II). The recombinant Ij-PLA2 protein exhibited PLA2 activity in the absence of Ca 2+, in contrast to canonical sPLA2 -I/II. Comparison of the amino acid sequences of Ij-PLA2 with the other sPLA2 -I/II suggests that the C-terminal extended peptide region of Ij-PLA2 is involved in its Ca 2+ -independent activity. Highlights: Two putative toxins were identified in RNA transcripts from Inimicus japonicus. Natterin homolog from I. japonicus consists of lectin and pore-forming domains. Recombinant PLA2 from I. japonicus exhibits Ca 2+ -independent PLA2 activity.