Tritrpticin is a member of the cathelicidin family of antimicrobial peptides. Starting from its native sequence (VRRFPWWWPFLRR), eight synthetic peptide analogs were studied to investigate the roles of specific residues in its biological and structural properties. This included amidation of the C-terminus paired with substitutions of its cationic and Phe residues, as well as the Pro residues that are important for its two-turn micelle-bound structure. These analogs were determined to have a significant antimicrobial potency. In contrast, two other peptide analogs, those with the three Trp residues substituted with either Phe or Tyr residues are not highly membrane perturbing, as determined by leakage and flip-flop assays using fluorescence spectroscopy. Nevertheless the Phe analog has a high activity; this suggests an intracellular mechanism for antimicrobial activity that may be part of the overall mechanism of action of native tritrpticin as a complement to membrane perturbation. NMR experiments of these two Trp-substituted peptides showed the presence of multiple conformers. The structures of the six remaining Trp-containing analogs bound to dodecylphosphocholine micelles showed major, well-defined conformations. These peptides are membrane disruptive and show a wide range in hemolytic activity. Their micelle-bound structures either retain the typical turn-turn structure of native tritrpticin or have an extended alpha-helix. This work demonstrates that closely related antimicrobial peptides can often have remarkably altered properties with complex influences on their biological activities.
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==About this Structure==
==About this Structure==
Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2I1F OCA].
Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2I1F OCA].
==Reference==
==Reference==
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[[Category: Micelle-bound peptide]]
[[Category: Micelle-bound peptide]]
[[Category: Turn]]
[[Category: Turn]]
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Revision as of 18:52, 28 July 2008
This article has been automatically seeded. Changes to this page should pertain to the PDB entry only and not to the protein or biomolecule in general.
Full experimental information is available from OCA.
ReferenceReference
Structure-function analysis of tritrpticin analogs: potential relationships between antimicrobial activities, model membrane interactions, and their micelle-bound NMR structures., Schibli DJ, Nguyen LT, Kernaghan SD, Rekdal O, Vogel HJ, Biophys J. 2006 Dec 15;91(12):4413-26. Epub 2006 Sep 22. PMID:16997878
