Sandbox Reserved 932: Difference between revisions

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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.

Three-finger toxins (3FTXs) are the most common family of snake venom proteins with a conserved structure. The core structure of 3FTXs is formed by <scene name='57/579702/Three_fingers/1'>three polypeptide loops</scene> joined together by disulphide bridges. Denmotoxin has several features which classify it as a non-conventional 3FTX. It differs structurally from other 3FTX venoms by its seven additional N-terminal amino acid residues; this unusually long N-terminus is unstructured and is hypothesized to gyrate above the core of the protein. There is also an additional fifth disulphide bridge at the first loop of the protein, which is not present in most 3FTXs. Another unique feature of denmotoxin is the twist at the tip of the central loop originating from a kink in a proline residue (Pro40). At the central loop, the charge is also negative, an arginine residue has been replaced with an aspartic acid, which is unusual for the proteins of the family.

===Structure===

Sandbox Reserved 932: Difference between revisions

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 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.
-Three-finger toxins (3FTXs) are the most common family of snake venom proteins with a conserved structure. The core structure of 3FTXs is formed by <scene name='57/579702/Three_fingers/1'>three polypeptide loops</scene> joined together by disulphide bridges. Denmotoxin has several features which classify it as a non-conventional 3FTX. It differs structurally from other 3FTX venoms by its seven additional N-terminal amino acid residues; this unusually long N-terminus is unstructured and is hypothesized to gyrate above the core of the protein. There is also an additional fifth disulphide bridge at the first loop of the protein, which is not present in most 3FTXs.  Another unique feature of denmotoxin is the twist at the tip of the central loop originating from a kink in a proline residue (Pro40).  At the central loop, the charge is also negative, an arginine residue has been replaced with an aspartic acid, which is unusual for the proteins of the family.
 ===Structure===