A computational study of venom as drug library: Discovery of multifunctional astacin-like metalloproteases from Androctonus zagrosensis venom gland transcriptome

Abstract

Astacin metalloproteases, zinc-dependent endopeptidases of the metzincin superfamily with medicinal potential, represent promising therapeutic targets. Recognizing scorpion venom as a rich drug discovery resource and acknowledging that computational approaches can accelerate the translation of these discoveries into treatments, we leveraged transcriptomic data as a 'drug discovery library' to identify venom astacin metalloproteinases (VAMPs) in the medically important scorpion Androctonus zagrosensis. Through a customized local database, we conducted the first comprehensive analysis of VAMPs, identifying 23 novel genes featuring the conserved HEXXHXXGXXH motif and characteristic domains (CUB, EGF-like, MAM). In detail, these were classified into four groups including scorpion tolloid proteins (scTLDs), BMP1/TLD-like proteinases, astacin-like metallopeptidases, and meprin A subunit β-like proteinases.

Domain architectures revealed evolutionary adaptations: scTLDs maintain a conserved five-CUB/two-EGF configuration, BMP1/TLD-like variants exhibit CUB/EGF diversity, astacin-like MPs retain only the catalytic domain, and meprin β-like proteinases feature an MAM domain. Physicochemical profiling showed subfamily-specific diversity (scTLDs: 1000–1008 aa/114 kDa; astacin-like: 240–250 aa). Expression analysis highlighted dominant scTLD2 production versus low meprin expression. Cysteine distribution diverged: scTLDs and BMP1/TLD-like variants contain 5 ZnMc-domain, 4 CUB-domain, and 6 EGF-like domain cysteines, while astacin-like and meprin β-like proteins have only 3 ZnMc cysteines, with meprin β uniquely adding 4 cysteines in its MAM domain. Protein interaction networks identified BMP1/TLD-like 2 as a central hub (highest degree/betweenness centrality), implicating its role in venom complexity. Phylogenetics resolved two clades (Clade 1: scTLDs and BMP1/TLD-like; Clade 2: astacin-like and meprin-like) with closest homology to Centruroides toxins. Gene ontology linked VAMPs to collagen processing, ECM remodeling, and developmental signaling. This work establishes scorpion venom astacin metalloproteinases as functionally diverse components, revealing new targets for antivenoms and biodiscovery.