Background: The protegrins are a family of arginine- and cysteine-rich cationic peptides found in porcine leukocytes that exhibit a broad range of antimicrobial and antiviral activities. They are composed of 16-18 amino- acid residues including four cysteines, which form two disulfide linkages. To begin to understand the mechanism of action of these peptides, we set out to determine the structure of protegrin-1 (PG-1). Results: We used two- dimensional homonuclear nuclear magnetic resonance spectroscopy to study the conformation of both natural and synthetic PG-1 under several conditions. A refined three-dimensional structure of synthetic PG-1 is presented. Conclusions: Both synthetic and natural protegrin-1 form a well-defined structure in solution composed primarily of a two-stranded antiparallel β sheet, with strands connected by a β turn. The structure of PG-1 suggests ways in which the peptide may interact with itself or other molecules to form the membrane pores and the large membrane-associated assemblages observed in protegrin-treated, gram-negative bacteria.
Fahrner, R. L., Dieckmann, T., Harwig, S. S. L., Lehrer, R. I., Eisenberg, D., & Feigon, J. (1996). Solution structure of protegrin-1, a broad-spectrum antimicrobial peptide from porcine leukocytes. Chemistry and Biology, 3(7), 543–550. https://doi.org/10.1016/S1074-5521(96)90145-3