Lipid-like behavior of signal sequence peptides at air–water interface

• Published in: Biochimica et biophysica acta Vol. 1828; no. 2; pp. 708 - 714
• Main Authors: Ambroggio, Ernesto E., Fidelio, Gerardo D.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-02-2013
• Subjects: Air; Amino Acid Sequence; Biophysics - methods; Interfacial peptide structure; Lateral surface stability; Lipids - chemistry; Micelles; Molecular Sequence Data; Peptide monolayer; Peptides - chemistry; Peptide–lipid interaction; PM-IRRAS; Protein Conformation; Protein Sorting Signals; Protein Structure, Secondary; Protein Transport; Signal sequence peptide; Sodium Chloride - chemistry; Spectroscopy, Fourier Transform Infrared - methods; Surface Properties; Water - chemistry; SSP; ASS; PSS; Lateral surface stability; ESS; PM-IRRAS; Peptide monolayer; Peptide–lipid interaction; Interfacial peptide structure; Signal sequence peptide; RTP
• ISSN: 0005-2736; 0006-3002; 1879-2642
• DOI: 10.1016/j.bbamem.2012.11.004

Several protein transport processes in the cell are mediated by signal sequence peptides located at the N-terminal side of the mature protein sequence. To date, the specific interaction and the stability of these peptides at the amphipathic interface of biological membranes and the relevance of the peptide conformation when they interact with lipids is not clear. We report the surface properties and the peptide–lipid interaction of three signal sequence peptides at the air–NaCl 145mM interface by using the Langmuir monolayer approach. These synthetic peptides have a natural sequence with a non-periodic amphiphilicity, where hydrophobic and hydrophilic residues are located on opposed sides of the peptide primary sequence. We show that signal sequence peptides form insoluble monolayers of high stability against lateral compression. At close packing, peptide molecular area, surface potential and the high stability of the peptide monolayer are indicative that signal sequence peptides are compatible with a β-sheet conformation at the interface. Structure was confirmed with PM-IRRAS and transmission FT-IR studies. The peptides show lateral miscibility with either POPC (a liquid-expanded lipid) or DPPC (a liquid-condensed lipid) in mixed peptide–lipid monolayers. This indicates that signal sequence peptides studied are laterally miscible with phospholipids independent of the phase state of the lipid.
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► The surface behavior of three hydrophobic signal sequence peptides is reported. ► These highly hydrophobic peptides mimic the surface behavior of lipids. ► A non-periodic amphiphilicity confers to peptide films high lateral stability. ► Surface and structural data show a beta-sheet structure at the air–water interface. ► Signal sequence peptides have lateral empathy with lipids regardless their physical state.