Tachyplesin: Difference between revisions

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<StructureSection load='1MA2' size='340' side='right' caption='1MA2' scene='67/671725/First_scene/1'>
<StructureSection load='1MA2' size='340' side='right' caption='1MA2' scene='67/671725/First_scene/1'>
Tachyplesin I (TPI) is an [http://en.wikipedia.org/wiki/Antimicrobial_peptides antimicrobial polypeptide] originally detected in Japanese [http://en.wikipedia.org/wiki/Horseshoe_crab Horse Shoe Crab].  
Tachyplesin I (TPI) is an [http://en.wikipedia.org/wiki/Antimicrobial_peptides antimicrobial polypeptide] originally detected in Japanese [http://en.wikipedia.org/wiki/Horseshoe_crab Horse Shoe Crab].  
The antimicrobial activity of peptides is closely related to the composition of the pathogen membrane and ability of the peptide to permeabilize the cell membranes. Bacteria and fungi have negatively charged membranes, and the interaction of <scene name='67/671725/Cationic_peptide_tpi/1'>cationic peptides such as tachyplesin I </scene> is mediated in large part by electrostatic interactions<ref name=Laederach>PMID:12369825</ref> (you can see the {{Template:ColorKey_Hydrophobic}} and {{Template:ColorKey_Polar}} amino acids).
The antimicrobial activity of the peptide is closely related to the composition of the pathogen membrane and ability of the peptide to permeabilize the cell membranes. Bacteria and fungi have negatively charged membranes, and the interaction of <scene name='67/671725/Cationic_peptide_tpi/1'>cationic peptides such as tachyplesin I </scene> is mediated in large part by electrostatic interactions<ref name=Laederach>PMID:12369825</ref> (you can see the {{Template:ColorKey_Hydrophobic}} and {{Template:ColorKey_Polar}} amino acids).


It shows high affinity for [http://en.wikipedia.org/wiki/Lipopolysaccharide lipopolysaccharides (LPS)] of [http://en.wikipedia.org/wiki/Gram-negative_bacteria gram-negative bacteria], thus neutralizing its effects. It has also been reported to inhibit the growth  of gram positive bacteria, fungui and viruses.
It shows high affinity for [http://en.wikipedia.org/wiki/Lipopolysaccharide lipopolysaccharides (LPS)] of [http://en.wikipedia.org/wiki/Gram-negative_bacteria gram-negative bacteria], thus neutralizing its effects. It has also been reported to inhibit the growth  of gram positive bacteria, fungui and viruses.
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== Structural highlights ==
== Structural highlights ==
The amino acid sequence of the TPI is NH₂-Lys-Trp-Cys-Phe-Arg-Val-Cys-Tyr-Arg-Gly-Ile-Cys-Tyr-Arg-Arg-Cys-Arg-CONH₂.  
The amino acid sequence of the TPI is NH₂-Lys-Trp-Cys-Phe-Arg-Val-Cys-Tyr-Arg-Gly-Ile-Cys-Tyr-Arg-Arg-Cys-Arg-CONH₂.  
It adopts a β-hairpin conformation in solution stabilized by teo cross-strand <scene name='67/671725/Disulfide_bonds/1'> disulfide bonds </scene>  between Cys³-Cys¹⁶ and Cys⁷-Cys¹², and its [http://en.wikipedia.org/wiki/Protein_primary_structure C-terminus is amidated].<ref name=Laederach>PMID:12369825</ref><ref name=Kushibiki>PMID:24389234</ref>
It adopts antiparallel β-sheet (hairpin) conformation in solution stabilized by teo cross-strand <scene name='67/671725/Disulfide_bonds/1'> disulfide bonds </scene>  between Cys³-Cys¹⁶ and Cys⁷-Cys¹², and its [http://en.wikipedia.org/wiki/Protein_primary_structure C-terminus is amidated].<ref name=Laederach>PMID:12369825</ref><ref name=Kushibiki>PMID:24389234</ref>


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