A-058. Antimicrobial Activity of the Immobilized Peptide, Cecropin P1: Role of Peptide Orientation on Potency

S. Arcidiacono, R. Kirby, A. M. Meehan, J. W. Soares;
US Army Natick Soldier Res., Dev., & Eng. Ctr., Natick, MA.

Antimicrobial peptides (AMPs) are part of an innate immune defense system in all organisms combating and preventing microbial infection. Extensive studies of AMP potency in solution have been performed; however, there has been only limited research on how covalent immobilization can influence AMP lysis behavior. Here, we covalently-attach the AMP cecropin P1 in two different orientations, c- and n- terminus, to a solid substrate and investigate the antimicrobial behavior of the tethered peptide compared to the native peptide in solution. Cecropin P1 was synthesized with a c- or n-terminus cysteine for covalent attachment to amine-functionalized magnetic microbeads. A PEO12 heterobifunctional linker (53.4Å) with an amine reactive NHS-ester on one end and a sulfhydryl-reactive maleimide on the other was employed to control the immobilized peptide orientation. A microtiter-plate based inhibition assay was utilized to evaluate activity of both immobilized and solution cecropin P1 against Escherichia coli ML35. Preliminary results suggest c-terminus immobilization of cecropin P1 reduced activity compared to that seen in solution. The microbeads and the linker-modified microbeads were also evaluated for activity. These controls did not exhibit any activity demonstrating that the reduced activity seen with the immobilized peptide is due to the act of tethering one end of the cecropin P1. C- and n- terminal immobilized cecropin P1 will also be evaluated for inhibition of target organisms, including Staphylococcus aureus, Acinetobacter baumanni, Pseudomonas aeruginosa, and Salmonella spp., to begin to understand the influence of immobilized peptide orientation on lytic behavior. The antimicrobial peptides’ intrinsic durability, stability and tailorability offer opportunities for their use in protection against a wide range of pathogenic organisms. The research presented here lays the foundation for a new generation of non-leaching antimicrobial coatings for medical devices, wound healing, and textiles.