Abstract (EN):
Lactoferrin is a glycoprotein with two globular lobes, each having two domains. Since the discovery of its
antimicrobial properties, efforts have been made to find peptides derived from this protein showing antimicrobial
properties. Most peptides initially studied were derived from Lactoferricin B, obtained from the protein by
digestion with pepsin. More recently, a new family of antimicrobial peptides (AMPs) derived from Lactoferrin
was discovered by Bolcher et al, and named Lactoferrampin (LFampin). The original sequence of LFampin
contained residues 268 – 284 from the N1 domain of Lactoferrin. From this peptide, the Bolscher’s group
synthesized a collection of peptides obtained by extension and / or truncation at the C or N-terminal sides,
in order to unravel the main structural features responsible for antimicrobial action. Here, we present results
for three of these peptides, namely LFampin 265 – 284, LFampin 265 – 280, and LFampin 270 – 284. The
peptides were tested against bacteria (E. coli and S. sanguinis), fungi (C. albicans), and model membranes of
1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), 1,2-dimyristoyl-sn-glycero-3-[phospho-rac-(1-glycerol)]
(DMPG), and their mixtures at a ratio of 3 : 1 (DMPC : DMPG (3 : 1)). The ability to adopt a helical conformation
was followed by a circular dichroism (CD), and the perturbation of the gel to the liquid-crystalline phase
transition of the membrane was characterized by differential scanning calorimetry (DSC). Distinct behavior
was observed in the three peptides, both from the microbiology and model membrane studies, with the
biophysical results showing excellent correlation with the microbiology activity studies. LFampin 265 – 284
was the most active peptide toward the tested microorganisms, and in the biophysical studies it showed the
highest ability to form an α-helix and the strongest interaction with model membranes, followed by LFampin
265 – 280. LFampin 270 – 284 was inactive, showing marginal secondary structure and no interaction with
the pathogen model membranes.
Language:
English
Type (Professor's evaluation):
Scientific
Contact:
mbastos@fc.up.pt (M. Bastos)
Notes:
Artigo convidado