Unravelling the mechanism of action of “de novo” designed peptide P1 with model membranes and gram-positive and gram-negative bacteria

Antimicrobial peptide GL13K immobilized onto SLA-treated titanium by silanization: antibacterial effect against methicillin-resistant Staphylococcus aureus (MRSA)

“…45 As a small molecule, GL13K could easily pass through the cell wall of bacteria as the peptidoglycan mesh is relatively porous. 46 As we know, bacterial membranes are negatively charged. 23 In contrast, most of the AMPs are cationic peptides, 47 so the electrostatic attraction between AMPs and bacterial membranes would ensure the attachment of AMPs, therefore providing the chance for AMPs to interact with the membranes and cause the death of the bacteria.…”

Physicochemical Features and Peculiarities of Interaction of AMP with the Membrane

“…Different steps of the interaction with the envelope can be distinguished. In the case of cationic AMPs, these steps are: attachment to the cell wall (Gram-negative bacteria, fungi) or outer membrane (Gram-negative bacteria) surface by electrostatic interactions; reaching the plasmatic membrane and insertion into the lipid bilayer because of hydrophobicity [6]; self-aggregation or forming of the aggregates with lipids in the case of peptides with the propensity to aggregation in the lipid environment [11][12][13]; and finally, appearance of defects (permanent or transient) in the morphology of membrane with accompanying leakage, or reversible (weak) changes and passing through the lipid bilayer without leakage [14,15]. AMP's physicochemical features and the compositions of the cell wall or outer membrane determine AMP's concentration on the plasma membrane surface and mode of interaction with the membrane [7].…”

“…Interaction with an envelope, as a rule, begins by binding to the outer layer of the envelope, which can be followed by either inhibition of the vital pathways in the outer layer of the envelope or by passing through it and reaching the plasma membrane. Taking into consideration the morphology of cell walls of Gram-positive bacteria and fungi, it is supposed that the majority of AMPs can overcome the outer layer barrier of these organisms and the plasma membrane is the main target for peptides [ 6 ]. In the case of Gram-negative bacteria, the outer barrier is also a lipid bilayer.…”

Zeta potential beyond materials science: Applications to bacterial systems and to the development of novel antimicrobials

“…In this kind of experiment, the antimicrobial agent accumulates on the bacterial surface in a charge-dependent manner and induces a change in the ZP that can provide information about the bacterialcompound interaction [10,11,35,87]. In an attempt to describe qualitatively and quantitatively how the bacterial surface interacts with different types of interfaces, the classical Derjaguin-Landau-Verwey-Overbeek (DLVO) theory of colloid stability has been applied.…”

“…Therefore, in recent years, some techniques frequently used to study model membranes began to be applied to bacteria, among them zeta potential (ZP) measurements [6,10,11]. The ZP, also known as electrokinetic potential [12], is determined by the net electrical charge of surface-exposed molecules, and it is an indirect method to estimate the surface potential of bacteria.…”