Cobra cytotoxin (CTX)

Cobra cytotoxins (CTXs), also widely known as cardiotoxins, are a major group of non-enzymatic proteins found in the venom of cobras, particularly those in the Naja genus. They belong to the three-finger toxin (3FTx) superfamily, characterized by a conserved structural motif of three beta-sheet loops extending from a central hydrophobic core stabilized by four disulfide bonds [1][2]. These toxins primarily function by binding to anionic phospholipids in the plasma membrane, leading to membrane pore formation, loss of cellular integrity, and subsequent necrosis or apoptosis [2][4]. In the context of snakebite envenomation, CTXs are the primary agents responsible for extensive local tissue destruction and can contribute to systemic effects such as cardiovascular failure and hemolysis [3][5]. From a therapeutic perspective, they are the critical targets for neutralization by antivenom antibodies, which prevent the toxins from docking onto host cell membranes. Furthermore, their potent and sometimes selective cytotoxic properties have led to significant research interest in their potential application as anti-tumor agents in oncology [4][5]. Sources: [1] UniProt Consortium. "Cytotoxin 1 - Naja atra (Chinese cobra)." [2] Dubovskii, P. V., et al. (2014). "Cobra cytotoxins: structural organization and membrane interactions." Toxins. [3] World Health Organization (WHO). "Guidelines for the Production, Control and Regulation of Snake Antivenom Sera." [4] Gasanov, S. E., et al. (2014). "Cobra venom cytotoxins; structural biology and cellular toxicity." Archives of Toxicology. [5] PubMed Central. "Mechanism of action of cobra venom cardiotoxins."

Other names

CardiotoxinDirect lytic factorDLFThree-finger toxin3FTxCobra venom cytotoxinMembrane-active polypeptide

Therapeutic antibodies in antivenom bind to the three-finger loops of the cytotoxin, sterically hindering its ability to interact with and insert into the host cell membrane phospholipids, thereby neutralizing its lytic activity [1][3].