BIOLOGICAL CHARACTERIZATION OF A NOVEL MAMMALIAN ANTIMICROBIAL PEPTIDE

A putative antimicrobial peptide of 34 residues was recently deduced f rom a bovine cathelicidin gene sequence and named BMAP-34. A peptide b ased on the deduced sequence was chemically synthesized and used to st udy the localization, structure and biological activities of BMAP-34. A Western blot analysis using antibodies raised to the synthetic pepti de showed that BMAP-34 is stored as preform in the cytoplasmic granule s of bovine neutrophils. CD spectroscopy indicates that the peptide as sumes an amphipathic alpha-helical conformation, as also predicted by secondary structure analysis. The peptide exerts a broad spectrum anti microbial activity against both Gram-negative and Gram-positive organi sms, and is not active against eukaryotic cells. When tested on Escher ichia coli ML-35, the kinetics of bacterial killing and of inner membr ane permeabilization are slower than those observed for other alpha-he lical peptides derived from cathelicidins. (C) 1998 Elsevier Science B .V. All rights reserved.