Conformational studies of an amphipathic peptide corresponding to human apolipoprotein A-II residues 18-30 with a C-terminal lipid binding motif EWLNS

Carry W. Buchko, Guangshun Wang, Gregory K. Pierens, Robert J. Cushley

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Abstract

A peptide was designed and synthesized to enhance the lipid binding properties of a 13-residue fragment of apolipoprotein A-II. The peptide, VTDYGKDLMEKVKEWLNS [apoA-II(18-30)+], contains a five-residue amphipathic motif, EWLNS, at the C-terminus of apolipoprotein A-II residues 18-30. The lipid binding properties of apoA-II(18-30)+ were assessed using optical spectroscopy in the presence of sodium dodecyl sulfate (SDS), dodecylphosphocholine (DPC), tetradecyltrimethyl ammonium chloride (TMA) and dimyristoylphosphatidylcholine (DMPC). The fluorescence emission spectra and the circular dichroism data suggested that apoA-II(18-30)+ interacted most strongly with SDS and most weakly with DMPC. An ensemble of structures for apoA-II(18-30)+ in aqueous solution containing SDS was calculated using distance geometry/simulated annealing methods from 308 NOE-based distance restraints. The backbone (N-C(α)-C=O) RMSD from the average structure of an ensemble of 15 out of 20 calculated structures was 0.54 ± 0.16 Å. Apart from some dynamic fraying at both termini, the distance geometry and simulated annealing calculations showed that apoA-II(18-30)+ adopted a well defined amphipathic helix with distinct hydrophobic and hydrophilic faces.

Original languageEnglish (US)
Pages (from-to)21-30
Number of pages10
JournalInternational Journal of Peptide and Protein Research
Volume48
Issue number1
StatePublished - Sep 5 1996

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Keywords

  • Amphipathic helix
  • Circular dichroism
  • Coronary artery disease
  • Distance geometry
  • Lipoproteins
  • Nuclear magnetic resonance

ASJC Scopus subject areas

  • Biochemistry

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