Tachyplesin: Difference between revisions
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The amino acid sequence of the TP-I 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 TP-I is NH₂-Lys-Trp-Cys-Phe-Arg-Val-Cys-Tyr-Arg-Gly-Ile-Cys-Tyr-Arg-Arg-Cys-Arg-CONH₂. | ||
[[Image:scheme1.jpg|150px|left|thumb|<b>Figure 1: Simplified model of Tachyplesin I.</b>]] | [[Image:scheme1.jpg|150px|left|thumb|<b>Figure 1: Simplified model of Tachyplesin I.</b>]] | ||
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TP-I undergoes a conformational change in the <scene name='67/671725/Tp_i_in_the_presence_of_lps/1'>presence of LPS </scene>. The backbone of the polypeptide becomes <scene name='67/671725/Conformation_change/8'>more rigid and twisted in the presence of LPS, than in the presence of water</scene>, making it more stable. | TP-I undergoes a conformational change in the <scene name='67/671725/Tp_i_in_the_presence_of_lps/1'>presence of LPS </scene>. The backbone of the polypeptide becomes <scene name='67/671725/Conformation_change/8'>more rigid and twisted in the presence of LPS, than in the presence of water</scene>, making it more stable. | ||
The two β-strands slightly extends when TP-I binds to LPS and stabilize the whole structure of TP-I as a result. [http://en.wikipedia.org/wiki/Nuclear_magnetic_resonance NMR] studies suggest that residues located in the N and C termini of TP-I are involved in the binding to LPS and that phosphate groups of LPS are in close proximity to TP-I. <ref name=Kushibiki>PMID:24389234</ref> | |||
Along with the requirement for β-hairpin conformation, there is a second requirement for activity and it is the ability to rearrange to a more amphiphilic conformation upon membrane association. | Along with the requirement for β-hairpin conformation, there is a second requirement for activity and it is the ability to rearrange to a more amphiphilic conformation upon membrane association. | ||
In the wild type TP-I,<scene name='67/671725/Conformation_change/9'> Arg 5 and Arg 14</scene>, | In the wild type TP-I,<scene name='67/671725/Conformation_change/9'> Arg 5 and Arg 14</scene>, provides this by acting as hinges.<ref name=Laederach>PMID:12369825</ref> | ||
