Abstract
The self-assembly in aqueous solution of three lipopeptides obtained from Bacillus subtilis has been investigated. The lipopeptides surfactin, plipastatin and mycosubtilin contain distinct cyclic peptide headgroups as well as differences in alkyl chain length, branching and chain length distribution. Cryogenic transmission electron microscopy and X-ray scattering reveal that surfactin and plipastatin aggregate into 2 nm-radius spherical micelles, whereas in complete contrast mycosubtilin self-assembles into extended nanotapes based on bilayer ordering of the lipopeptides. Circular dichroism and FTIR spectroscopy indicate the presence of turn structures in the cyclic peptide headgroup. The unexpected distinct mode of self-assembly of mycosubtilin compared to the other two lipopeptides is ascribed to differences in the surfactant packing parameter. This in turn is due to specific features of the conformation of the peptide headgroup and alkyl chain branching.
Highlights
Bioactive lipopeptides are attracting attention due to their ready production using fermentation methods.[1]
The formation of a bilayer structure by mycosubtilin indicates a surfactant packing parameter p 1⁄4 v/al z1 where v is the volume of the hydrophobic chain, a is the effective area per headgroup and l is the lipid chain length
P is smaller for surfactin and plipastatin, such that spherical micelles are formed. This may be due to larger l values for the unbranched lipid chains, the effective headgroup area will differ due to the distinct conformations and electrostatics of the cyclic peptide units
Summary
Bioactive lipopeptides are attracting attention due to their ready production using fermentation methods.[1]. The formation of a bilayer structure by mycosubtilin indicates a surfactant packing parameter p 1⁄4 v/al z1 where v is the volume of the hydrophobic chain, a is the effective area per headgroup and l is the lipid chain length. P is smaller for surfactin and plipastatin, such that spherical micelles are formed.
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call