Interaction of a novel antimicrobial peptide isolated from
the venom of solitary bee Colletes daviesanus with phospholipid vesicles and
Escherichia coli cells
J Pept Sci. 2014 Aug 14
The peptide named codesane (COD), consisting of 18 amino
acid residues and isolated from the venom of wild bee Colletes daviesanus
(Hymenoptera : Colletidae), falls into the category of cationic α-helical
amphipathic antimicrobial peptides. In our investigations, synthetic COD
exhibited antimicrobial activity against Gram-positive and Gram-negative
bacteria and Candida albicans but also noticeable hemolytic activity. COD and
its analogs (collectively referred to as CODs) were studied for the mechanism
of their action.
The interaction of CODs with liposomes led to significant
leakage of calcein entrapped in bacterial membrane-mimicking large unilamellar
vesicles made preferentially from anionic phospholipids while no calcein
leakage was observed from zwitterionic liposomes mimicking membranes of
erythrocytes. The preference of CODs for anionic phospholipids was also
established by the blue shift in the tryptophan emission spectra maxima when
the interactions of tryptophan-containing COD analogs with liposomes were
examined.
Those results were in agreement with the antimicrobial and hemolytic
activities of CODs. Moreover, we found that the studied peptides permeated both
the outer and inner cytoplasmic membranes of Escherichia coli. This was
determined by measuring changes in the fluorescence of probe
N-phenyl-1-naphthylamine and detecting cytoplasmic β-galactosidase released
during the interaction of peptides with E. coli cells. Transmission electron
microscopy revealed that treatment of E. coli with one of the COD analogs
caused leakage of bacterial content mainly from the septal areas of the cells
No comments:
Post a Comment