Tachyplesin: Difference between revisions

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Janak Raj Joshi, Shulamit Idzikowski, Michal Harel, Alexander Berchansky, Joel L. Sussman, Angel Herraez, Jaime Prilusky

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	The sequence adapts an antiparallel β-sheet (hairpin) conformation in solution, with a <scene name='67/671725/Beta_turn_tp-1/2'>β-turn</scene> for the centrally located residues <scene name='67/671725/Tyrargglyile/3'>Tyr-Arg-Gly-Ile</scene>, stabilized by two cross-strand <scene name='67/671725/Disulfide_bonds/4'> disulfide bonds </scene> between Cys³-Cys¹⁶ and Cys⁷-Cys¹²<ref name=Saravanan>PMID:22464970</ref><ref name=Nakamura>Nakamura, Takanori, et al. "Tachyplesin, a class of antimicrobial peptide from the hemocytes of the horseshoe crab (''Tachypleus tridentatus''). Isolation and chemical structure." Journal of Biological Chemistry 263.32 (1988): 16709-16713</ref>, and [http://en.wikipedia.org/wiki/Protein_primary_structure C-terminus amidation]. In addition there are H-bonds and aromatic rings stacking interactions which helps stabilize the hairpin loop structure of the peptide.		The sequence adapts an antiparallel β-sheet (hairpin) conformation in solution, with a <scene name='67/671725/Beta_turn_tp-1/2'>β-turn</scene> for the centrally located residues <scene name='67/671725/Tyrargglyile/3'>Tyr-Arg-Gly-Ile</scene>, stabilized by two cross-strand <scene name='67/671725/Disulfide_bonds/4'> disulfide bonds </scene> between Cys³-Cys¹⁶ and Cys⁷-Cys¹²<ref name=Saravanan>PMID:22464970</ref><ref name=Nakamura>Nakamura, Takanori, et al. "Tachyplesin, a class of antimicrobial peptide from the hemocytes of the horseshoe crab (''Tachypleus tridentatus''). Isolation and chemical structure." Journal of Biological Chemistry 263.32 (1988): 16709-16713</ref>, and [http://en.wikipedia.org/wiki/Protein_primary_structure C-terminus amidation]. In addition there are H-bonds and aromatic rings stacking interactions which helps stabilize the hairpin loop structure of the peptide.

	[http://en.wikipedia.org/wiki/Nuclear_magnetic_resonance NMR] studies have shown that TP-I undergoes a conformational change from <scene name='67/671725/First_scene/5'>water surrounding</scene> to <scene name='67/671725/Tp_i_in_the_presence_of_lps/4'>presence of LPS</scene>, making it <scene name='67/671725/Conformation_change/15'>more rigid and twisted</scene> than in the presence of water<ref name=Kushibiki>PMID:24389234</ref>. Moreover a docking model suggests the stability of the structure of TP-I is increased in the presence of LPS by the binding of the N and C termini of TP-I to LPS. The conformational change of TP-I seems to be crucial for its antimicrobial activity, since rearrangement of TP-I structure makes it more amphiphilic to negatively charged membrane of bacteria and fungus<ref name=Laederach>PMID:12369825</ref>.		[http://en.wikipedia.org/wiki/Nuclear_magnetic_resonance NMR] studies have shown that TP-I undergoes a conformational change from <scene name='67/671725/First_scene/5'>water surrounding</scene> to <scene name='67/671725/Tp_i_in_the_presence_of_lps/4'>presence of LPS</scene>, making it <scene name='67/671725/Conformation_change/14'>more rigid and twisted</scene> than in the presence of water<ref name=Kushibiki>PMID:24389234</ref>. Moreover a docking model suggests the stability of the structure of TP-I is increased in the presence of LPS by the binding of the N and C termini of TP-I to LPS. The conformational change of TP-I seems to be crucial for its antimicrobial activity, since rearrangement of TP-I structure makes it more amphiphilic to negatively charged membrane of bacteria and fungus<ref name=Laederach>PMID:12369825</ref>.