Puzzling Permeating Peptides

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Antimicrobial peptides are toxins that either (a) disrupt the integrity of cellular membranes or (b) instigate their own passage through these membranes on their way to intracellular targets. However, the mechanisms by which these peptides interact with a lipid bilayer (the defining component of a cell membrane) are poorly understood. Furthermore, given that a characteristic of lipid bilayers is to prevent the permeation of charged solutes, it remains puzzling why antimicrobial peptides are largely ionic.

In our letter, we use massively repeated computer simulations to quantify the favorable insertion of the antimicrobial peptide indolicidin into a lipid bilayer. The simulations suggest that a single molecule of indolicidin is capable of thinning and permeabilizing the lipid bilayer. The balance of hydrophobicity, charge, and structural disorder in this antimicrobial peptide appears to be well-suited to disrupt cell membranes, even in the absence of peptide aggregation or the formation of an ordered structure. Moreover, we emphasize the necessity of lengthy and massively repeated simulations to attain and gauge convergence of the calculations.

The image shows a simulation snapshot in which monomeric, intrinsically disordered indolicidin (yellow) resides in the bilayer’s hydrophobic core (white) and interacts with zwitterionic headgroups (brown) in both leaflets, drawing them inward and deforming the bilayer, causing the influx of water (cyan). Water and lipid in the foreground have been omitted for clarity.

We see science-as-art in cases where an image conveys a profound new scientific insight. That is, the beauty of the image does not solely arise from color, composition, or artistic flair, but also, crucially, in the novel understanding that it provides or represents. It is only in this respect that we consider ourselves artists. As such, our aspirations for our next science-as-art submission are intimately related to our basic scientific goals.

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–Chris Neale

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One thought on “Puzzling Permeating Peptides

  1. Peptides are short polymers of amino corrosive monomers connected by peptide bonds. They are recognized from proteins on the premise of size, commonly holding short of what 50 monomer units. A peptide is shaped by joining two or more amino acids. At the point when the amount of amino acids is not exactly something like 50 these particles are named peptides while bigger successions are alluded to as proteins. The amino acids are coupled by a peptide bond, an extraordinary linkage in which the nitrogen particle of one amino corrosive ties to the carboxyl carbon iota of an alternate.

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