Solvent-induced α- to 3(10)-helix transition of an amphiphilic peptide

Biochemistry. 2013 Oct 8;52(40):7137-44. doi: 10.1021/bi400537z. Epub 2013 Sep 25.

Abstract

The amphiphilic peptide of the triacylglycerol lipase derived from Pseudomonas aeruginosa plays a critical role in guarding the gate for ligand access. Conformations of this peptide at several water-oil interfaces and in protein environments were compared using atomistic simulations with explicit solvents. In oil-containing solvents, this peptide is able to retain a folded structure. Interestingly, when the peptide is immersed in a low-polarity solvent environment, it exhibits a "coalesced" helix structure, which has both α- and 3(10)-helix components. The observation that the 3(10)-helical conformation is populated in a highly nonpolar environment is consistent with a previous report on polymethylalanine. Frequent interconversions of the secondary structure (between α-helix and 3(10)-helix) of the peptide are also observed. We further studied how this solvent-induced structural transition may be connected to the trigger mechanism of lipase gating and how the lipase senses the hydrophobic-hydrophilic interface.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Apolipoproteins / chemistry
  • Humans
  • Hydrophobic and Hydrophilic Interactions
  • Lipase / chemistry*
  • Peptides / chemistry
  • Protein Conformation
  • Protein Structure, Secondary / drug effects*
  • Pseudomonas aeruginosa / enzymology
  • Solvents / chemistry*
  • Surface-Active Agents / chemistry

Substances

  • Apolipoproteins
  • Peptides
  • Solvents
  • Surface-Active Agents
  • Lipase