Antimicrobial peptoid interactions with model membrane mimics at an air-liquid interface


Michelle T. Dohm, m-dohm@northwestern.edu1, Andrey Ivankin, aivankin@iit.edu2, Nathaniel P. Chongsiriwatana3, Chao Liu, liuchao@iit.edu2, Annelise E. Barron, a-barron@northwestern.edu3, and David Gidalevitz, gidalevitz@iit.edu2. (1) Department of Chemistry, Northwestern Univeristy, 2145 Sheridan Road, Evanston, IL 60208, (2) Department of Chemical Engineering, Illinois Institute of Technology, Chicago, IL 60616, (3) Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Rd, Evanston, IL 60208
Poly-N-substituted glycines (“peptoids”) have demonstrated potential to act as good non-natural mimics of antimicrobial peptides, which are of interest for the treatment of multi-drug-resistant bacterial infections. Peptoid 1 is both a potent and cell-selective mimic inspired by the helical, cationic, and globally amphipathic structure of magainin-2-amide. Interactions of 1 with model lipid monolayers were studied using X-ray reflectivity and grazing incidence X-ray diffraction on a liquid surface. 1 was injected into the subphase beneath a pure lipid monolayer representing a simplified outer leaflet of either bacterial or mammalian cell membranes. The lipid phase morphology before and after the addition of 1 was visualized by epifluorescence microscopic imaging. Insertion of 1 into anionic rather than zwitterionic lipid monolayers strongly supports the activity trends observed in antimicrobial and hemolytic assays. The extent and possible orientation of 1 insertion suggest that antimicrobial peptoids may operate by mechanisms analogous to their natural peptide counterparts.

Biological Surface Chemistry
8:30 AM-11:50 AM, Monday, March 26, 2007 McCormick Place South -- Room S404A, Level 4, Oral

Division of Colloid & Surface Chemistry

The 233rd ACS National Meeting, Chicago, IL, March 25-29, 2007