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.

Denmotoxin is a monomeric protein comprising of 77 amino acid residues. Denmotoxin consists of <scene name='57/579702/Three_fingers/1'>three polypeptide loops</scene> protruding from the globular core; this structure is typical for 3FTXs. The globular core consists of a <scene name='57/579702/3ftx_beta_strands/2'>triple stranded anti-parallel β-sheet</scene> ; two of the β-strands in this structure connect to the second loop (central loop) and one β-strand connects to the third loop. There are two highly <scene name='57/579702/Flexible_regions/2'>flexible regions</scene> on the protein: one at the tip of the central loop and one at the 3 first residues of the N-terminus; the expected active site of denmotoxin is at the tip of the central loop.

There are 10 structurally important cysteine-residues in denmotoxin which form five stabilizing <scene name='57/579702/Disulphides/3'>disulphide bonds</scene>. Four of these disulphide bonds, which are found in all 3FTXs are located at the central core and the fifth additional bond is found at the tip of the first loop. The cysteine residues of all 3FTXs are highly conserved, whereas the other residues within the sequence express high variability. Denmotoxin possesses most of the conserved residues invariant among 3FTXs which have been shown to be important for the proper folding of and structure of protein. The presence of these structurally important residues result in the characteristic three finger fold of the toxin (e.g. Gly52, Pro58).

Multiple sequence alignment of denmotoxin reveals that the venom belongs to the family of non-conventional 3FTXs. All non-conventional 3FTXs have an additional disulphide bond. Denmotoxin has 7 additional amino acid residues in its N-terminal when compared to other 3FTXs; the N-terminus is also blocked by a pyroglutamic acid residue. This unusually long N-terminus is unstructured and is hypothesized to gyrate above the core of the protein. 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.

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.
+Denmotoxin is a monomeric protein comprising of 77 amino acid residues. Denmotoxin consists of <scene name='57/579702/Three_fingers/1'>three polypeptide loops</scene> protruding from the globular core; this structure is typical for 3FTXs. The globular core consists of a <scene name='57/579702/3ftx_beta_strands/2'>triple stranded anti-parallel β-sheet</scene> ; two of the β-strands in this structure connect to the second loop (central loop) and one β-strand connects to the third loop. There are two highly <scene name='57/579702/Flexible_regions/2'>flexible regions</scene> on the protein: one at the tip of the central loop and one at the 3 first residues of the N-terminus; the expected active site of denmotoxin is at the tip of the central loop.
+There are 10 structurally important cysteine-residues in denmotoxin which form five stabilizing <scene name='57/579702/Disulphides/3'>disulphide bonds</scene>. Four of these disulphide bonds, which are found in all 3FTXs are located at the central core and the fifth additional bond is found at the tip of the first loop. The cysteine residues of all 3FTXs are highly conserved, whereas the other residues within the sequence express high variability. Denmotoxin possesses most of the conserved residues invariant among 3FTXs which have been shown to be important for the proper folding of and structure of protein. The presence of these structurally important residues result in the characteristic three finger fold of the toxin (e.g. Gly52, Pro58).
+Multiple sequence alignment of denmotoxin reveals that the venom belongs to the family of non-conventional 3FTXs. All non-conventional 3FTXs have an additional disulphide bond. Denmotoxin has 7 additional amino acid residues in its N-terminal when compared to other 3FTXs; the N-terminus is also blocked by a pyroglutamic acid residue. This unusually long N-terminus is unstructured and is hypothesized to gyrate above the core of the protein. 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.