Snake Venom Three‐Finger Neurotoxins and Neurotoxin‐Like Proteins: Insights Into Their Structural and Functional Aspects Along With Their Pharmacological Potential

The three-finger neurotoxins interfere with cholinergic transmission at various postsynaptic sites in the peripheral and central nervous systems. Based on receptor selectivity, the neurotoxins can be broadly classified as α-neurotoxins, k-neurotoxins and muscarinic toxins. The three-finger neurotoxins are nonenzymatic and possess a conserved structural feature consisting of loops of β-stranded loops protruding from a globular hydrophobic core held together by conserved disulfide bonds. The snake venom neurotoxins were first reported approximately 60 years ago, and their discovery has since expanded our knowledge of membrane receptors and ion channels. The interactions of these neurotoxins with receptors are of special interest for their potential use in the treatment of neurodegenerative diseases, pain and cancer. This review focuses on the snake venom neurotoxins and neurotoxin-like proteins and their subtypes, structural aspects of their mechanisms of action and specificity for receptors or ligand-binding interfaces. Further, a detailed discussion is added on the pharmacological potential of these toxins for use as probes or potential targets in drug discovery.