Scolopendin 2, a cationic antimicrobial peptide from centipede, and its membrane-active mechanism

Abstract

Scolopendin 2 is a 16-mer peptide (AGLQFPVGRIGRLLRK) derived from the centipede Scolopendra subspinipes mutilans. We observed that this peptide exhibited antimicrobial activity in a salt-dependent manner against various fungal and bacterial pathogens and showed no hemolytic effect in the range of 1.6 μM to 100 μM. Circular dichroism analysis showed that the peptide has an α-helical properties. Furthermore, we determined the mechanism(s) of action using flow cytometry and by investigating the release of intracellular potassium. The results showed that the peptide permeabilized the membranes of Escherichia coli O157 and Candida albicans, resulting in loss of intracellular potassium ions. Additionally, bis-(1,3-dibutylbarbituric acid) trimethine oxonol and 3,3'-dipropylthiacarbocyanine iodide assays showed that the peptide caused membrane depolarization. Using giant unilamellar vesicles encapsulating calcein and large unilamellar vesicles containing fluorescein isothiocyanate-dextran, which were similar in composition to typical E. coli O157 and C. albicans membranes, we demonstrated that scolopendin 2 disrupts membranes, resulting in a pore size between 4.8 nm and 5.0 nm. Thus, we have demonstrated that a cationic antimicrobial peptide, scolopendin 2, exerts its broad-spectrum antimicrobial effects by forming pores in the cell membrane.

Expression, purification and characterization of the recombinant cysteine-rich antimicrobial peptide snakin-1 in Pichia pastoris

“…Thus, diSC 3 (5) quenched its own fluorescence. If the cytoplasmic membrane is damaged by peptide or other agents, diSC 3 (5) dye will be released into the surrounding medium, causing a rapid increase in fluorescence [36]. In our study, SN-1 peptide induced different levels of depolarization of the cytoplasmic membrane in a dose-dependent manner (Fig.…”

“…Antibacterial assays were performed with three strains of bacteria, i.e., Gram-positive The ability of the recombinant SN-1 to depolarize the bacterial cytoplasmic membrane was determined using a membrane potential-sensitive fluorescent dye diSC 3 (5) and standard melittin (10 μM), as described previously [36]. Briefly, E. coli cells in mid-log phase were washed twice in buffer (10 mM HEPES, 20 mM glucose, 0.2 mM EDTA, (Fig.…”

“…In addition, the membrane activity of SN-1 was also determined by an inner membrane permeability assay using diSC 3 (5) dye as the indicator of membrane potential. When this dye was added to the E. coli cell suspensions for incubation, a large portion of diSC 3 (5) was taken up and concentrated in the cytoplasmic membrane of E. coli cells, where it bound to the lipid rich intracellular components [36]. Thus, diSC 3 (5) quenched its own fluorescence.…”

A Chitin-binding Protein Purified from Moringa oleifera Seeds Presents Anticandidal Activity by Increasing Cell Membrane Permeability and Reactive Oxygen Species Production

“…The antifungal mode of action of Mo -CBP 2 is probably linked to its ability to disrupt the cell membrane integrity of C. albicans , as propidium iodide, which is membrane impermeable, was taken up by cells exposed to Mo -CBP 2 , and interacted with nucleic acids as revealed by the appearance of red fluorescence (Wang et al, 2015). Increasing permeability of cell membrane can result from depolarization, disruption of lipid domain organization, pore formation, and unbalance of intracellular electrochemical gradients, leading to loss of membrane functions and cell death (Lee and Lee, 2015; Lee et al, 2015). We hypothesize that the increased permeability of C. albicans cell membrane by Mo -CBP 2 exposure might be due to interaction of this protein with chitin, which is one of the major components of fungal cell walls.…”

Exploring the global animal biodiversity in the search for new drugs – Spiders, scorpions, horseshoe crabs, sea spiders, centipedes, and millipedes

“…Several of these compounds displayed potent activity against Gram-positive and Gramnegative bacteria as well as fungi while causing no or only moderate hemolysis [210][211][212][213][214][215][216]. The mechanism of action of these compounds may involve the activation of a potentially novel apoptotic pathway [217] following the accumulation of reactive oxygen species [214], binding to the surface of fungi or bacteria and interaction with certain membrane components [211,218,219], and/or the formation of pores in the cell membrane [215].…”