NnM469, a novel recombinant jellyfish venom metalloproteinase from Nemopilema nomurai, disrupted the cell matrix

Molecular cloning and functional characterization of Nemopilema nomurai venom metalloproteinases have provided deeper insights into the pathogenesis of jellyfish dermatitis. This study reports a new cDNA clone from N. nomurai tentacle venom (Transcript sequence: ID469) encoding 362 amino acid residues, belonged to astacin family and capable of disrupting the cell matrix. The N. nomurai metalloproteinase 469 (NnM469) comprises a signal peptide and propeptide, followed by metalloproteinase domain containing a zinc-binding motif, and two ShKT domains. Notably, NnM469 features a zinc-binding motif (HEXXH) at the active site, within an extended sequence of HEXXHXXGFXHE, which is unique to astacin. Immunocytochemistry revealed that NnM469 is located in the stab tube and envelope of jellyfish nematocysts. Western blot and LC-MS/MS analysis confirmed that the NnM469 protein was successfully expressed using the Pichia pastoris expression system. The recombinant NnM469 could degrade the cell matrix, resulting in the death of HaCaT cells with an IC₅₀ of 26.34 μg/mL. Finally, I-TASSER-generated structure and function predictions indicated that conserved Asp⁵³, His¹⁶⁸, His¹⁷², His¹⁷⁸, and Tyr²²⁷ serve as key amino acid residues for the Zn²⁺ ion binding in the catalytic center. In summary, the study of the molecular characteristics and function of NnM469 presents an opportunity to develop therapeutic interventions for jellyfish venom-induced dermatitis.