1ytr
From Proteopedia
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NMR structure of plantaricin a in dpc micelles, 20 structures
Overview
The three-dimensional structure in dodecyl phosphocholine micelles of the, 26-mer membrane-permeabilizing bacteriocin-like pheromone plantaricin A, (PlnA) has been determined by use of nuclear magnetic resonance, spectroscopy. The peptide was unstructured in water but became partly, structured upon exposure to micelles. An amphiphilic alpha-helix, stretching from residue 12 to 21 (possibly also including residues 22 and, 23) was then formed in the C-terminal part of the peptide, whereas the, N-terminal part remained largely unstructured. PlnA exerted its, membrane-permeabilizing antimicrobial activity through a nonchiral, interaction with the target cell membrane because the d-enantiomeric form, had the same activity as the natural l-form. This nonchiral interaction, involved the amphiphilic alpha-helical region in the C-terminal half of, PlnA because a 17-mer fragment that contains the amphiphilic alpha-helical, part of the peptide had antimicrobial potency that was similar to that of, the l- and d-enantiomeric forms of PlnA. Also the pheromone activity of, PlnA depended on this nonchiral interaction because both the l- and, d-enantiomeric forms of the 17-mer fragment inhibited the pheromone, activity. The pheromone activity also involved, however, a chiral, interaction between the N-terminal part of PlnA and its receptor because, high concentrations of the l-form (but not the d-form) of a 5-mer fragment, derived from the N-terminal part of PlnA had pheromone activity. The, results thus reveal a novel mechanism whereby peptide pheromones such as, PlnA may function. An initial nonchiral interaction with membrane lipids, induces alpha-helical structuring in a segment of the peptide pheromone., The peptide becomes thereby sufficiently structured and properly, positioned in the membrane interface, thus enabling it to engage in a, chiral interaction with its receptor in or near the membrane water, interface. This membrane-interacting mode of action explains why some, peptide pheromones/hormones such as PlnA sometimes display antimicrobial, activity in addition to their pheromone activity.
About this Structure
1YTR is a Single protein structure of sequence from [1]. Full crystallographic information is available from OCA.
Reference
Structure and mode of action of the membrane-permeabilizing antimicrobial peptide pheromone plantaricin A., Kristiansen PE, Fimland G, Mantzilas D, Nissen-Meyer J, J Biol Chem. 2005 Jun 17;280(24):22945-50. Epub 2005 Apr 1. PMID:15805109
Page seeded by OCA on Wed Nov 21 07:02:47 2007
