De novo design of antimicrobial peptides with broad spectrum activity and specificity between bacterial and human cell membranes

ORGN 2

Robert S. Hodges, robert.hodges@uchsc.edu, Department of Biochemistry and Molecular Genetics, University of Colorado Health Sciences Center, UCHSC at Fitzsimons, P.O. Box 6511 MS 8101, Aurora, CO 80045
The emergence of pathogenic bacteria with clinically significant resistance to conventional antibiotics is a major public health concern. The development of a new class of antibiotics has become critical. The designed cationic antimicrobial peptides whose sole target is the cytoplasmic membrane could represent such a class since the development of resistance is not expected because this would require substantial changes in the lipid composition of the cell membranes of microorganisms. Utilizing a structure-based rational approach to antimicrobial peptide design in two structural classes of peptides (cyclic beta-sheet and alpha-helical) we were able to develop antimicrobial peptides with improved activity, specificity and clinical potential as broad spectrum antibiotics. The controlled disruption of beta-sheet and alpha-helical structure (disruption under benign conditions and inducible in hydrophobic conditions) is related to strong antimicrobial activity over a variety of Gram-negative and Gram-positive bacterial strains and specificity to human cells (no detectable hemolytic activity). These results have led to a new proposed mechanism of action of antimicrobial peptides in biomembranes.