posted on 2005-05-17, 00:00authored byRaymond T. Syvitski, Ian Burton, Neil R. Mattatall, Susan E. Douglas, David L. Jakeman
Pleurocidin is an antimicrobial peptide that was isolated from the mucus membranes of winter
flounder (Pseudopleuronectes americanus) and contributes to the initial stages of defense against bacterial
infection. From NMR structural studies with the uniformly 15N-labeled peptide, a structure of pleurocidin
was determined to be in a random coil conformation in aqueous solution whereas it assumes an α-helical
structure in TFE and in dodecylphosphocholine (DPC) micelles. From 15N relaxation studies, the helix is
a rigid structure in the membrane-mimicking environment. Strong NOESY cross-peaks from the pleurocidin
to the aliphatic chain on DPC confirm that pleurocidin is contained within the DPC micelle and not
associated with the surface of the micelle. From diffusion studies it was determined that each micelle
contains at least two pleurocidin molecules.