1.C.62 The Pseudopleuronectes americanus (flounder) Pleurocidin (Pleurocidin) Family
Pleurocidin is an antibacterial peptide that forms ion channels in planar lipid bilayers. Its activity depends on the presence of small amounts of anionic phospholipids such as phosphatidyl serine. The channel, probably a toroidal pore, is not voltage dependent and displays only one unitary conductance. It is active against Gram-negative and Gram-positive bacteria and plays a role in host defense by forming pores that induce cell lysis. Pleurocidin is 25 aas long and is derived from a 60 or 68 aa precursor prepropolypeptide. At least three such precursors of similar but different amino acid sequence have been sequenced from P. americanus.
The Pleurocidin family is related to the Dermaseptin family of amphibian peptide (TC #1.C.52) toxins as well as the insect ceratotoxins (Bessin et al., 2004) and the insect cecropins (TC #1.C.17).
The transport reaction catalyzed by pleurocidin is: