Sandbox Reserved 932: Difference between revisions
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Three-finger toxins (3FTXs) are the most common family of snake venom proteins; these venoms can be found in ''elapid'', ''colubrid'' and ''hydrophiid'' snakes and include toxins such as α-cobratoxin and α-bungarotoxin. 3FTXs are non-enzymatic proteins which form a structurally conserved superfamily whose members all share a highly conserved structure. <ref name=Dufton/><ref name=Endo/> The core structure of 3FTXs is formed by three <scene name='57/579702/Three_fingers/1'>three β-stranded polypeptide loops</scene> joined together by four conserved disulphide bridges located in the <scene name='57/579702/3ftx_beta_strands/2'>core</scene> of the protein. Despite the similarities in the structure of different toxins belonging to the family, the 3FTXs from various venoms have a variety of receptors/acceptors and exhibit differential responses in their targets. The members of the family can vary slightly in: the length and type of twists of the tree loops; the length and type of turns of the N and C-terminal tail and the amount of β-sheets in the overall structure. These differences allow for the specificity and toxicity of the proteins to their targets. <ref name=Pawlak/> | Three-finger toxins (3FTXs) are the most common family of snake venom proteins; these venoms can be found in ''elapid'', ''colubrid'' and ''hydrophiid'' snakes and include toxins such as α-cobratoxin and α-bungarotoxin. 3FTXs are non-enzymatic proteins which form a structurally conserved superfamily whose members all share a highly conserved structure. <ref name=Dufton/><ref name=Endo/> The core structure of 3FTXs is formed by three <scene name='57/579702/Three_fingers/1'>three β-stranded polypeptide loops</scene> joined together by four conserved disulphide bridges located in the <scene name='57/579702/3ftx_beta_strands/2'>core</scene> of the protein. Despite the similarities in the structure of different toxins belonging to the family, the 3FTXs from various venoms have a variety of receptors/acceptors and exhibit differential responses in their targets. The members of the family can vary slightly in: the length and type of twists of the tree loops; the length and type of turns of the N and C-terminal tail and the amount of β-sheets in the overall structure. These differences allow for the specificity and toxicity of the proteins to their targets. <ref name=Pawlak/> | ||
Denmotoxin shares approximately 30% sequence similarity with other 3FTXs with an exception of exhibiting approximately 50% sequence similarity with another colubrid snake venom α-colubritoxin. Despite the relatively low sequence similarity, denmotoxin possesses all the residues needed to maintain the 3 finger fold. A large part of the sequence similarity between denmotoxin and other 3FTXs is due to the highly conserved disulphides and a number of structurally important residues. | Denmotoxin shares approximately 30% sequence similarity with other 3FTXs with an exception of exhibiting approximately 50% sequence similarity with another colubrid snake venom α-colubritoxin. Despite the relatively low sequence similarity, denmotoxin possesses all the residues needed to maintain the 3 finger fold. A large part of the sequence similarity between denmotoxin and other 3FTXs is due to the highly conserved disulphides and a number of structurally important residues. Denmotoxin belongs to a subdivision of non-conventional three-finger toxins; the novel features of denmotoxin are discussed below. <ref name=Pawlak/> | ||
===Structure of the non-conventional 3FTX denmotoxin=== | ===Structure of the non-conventional 3FTX denmotoxin=== | ||
