Short-chain diacyl phosphatidylglycerols: Which one to choose for the NMR structural determination of a membrane-associated peptide from Escherichia coli?

Guangshun Wang, Paul A. Keifer, Alan Peterkofsky

Research output: Contribution to journalArticle

15 Scopus citations


Diacyl phosphatidylglycerols (PG) are the major anionic lipids in the Escherichia coli membrane. Short-chain dihexanoyl phosphatidylglycerol (DHPG) was previously utilized for the structural determination, by NMR spectroscopy, of the peptide corresponding to the N-terminal membrane anchor of the glucose-specific enzyme IIA (IIAGlc) from E. coli. This study explores the possible use of lipid micelles of dioctanoyl phosphatidylglycerol (DOPG) and didecanoyl phosphatidylglycerol (DDPG) as alternatives to DHPG. At a peptide concentration of 1 mM, the minimum peptide/lipid molar ratios required for the formation of the lipid-binding amphipathic helix are approximately 1:40, 1:5, and 1:5 for DHPG, DOPG, and DDPG, respectively. Based on the lipid titration, the critical micelle concentration (CMC) of DHPG was estimated to be ∼50 mM. The 1H spectral linewidths of the peptide bound to a variety of lipid micelles decrease in the following order: DDPG > DOPG > DHPG. The helical regions of the peptide in different anionic lipids were elucidated based on chemical shift indexes (CSI). Residues Leu2-Leu9, Leu2-Val10, and Leu2-Val10 were found to be helical in DHPG, DOPG, and DDPG, respectively, indicating that the lipid chain length had only a subtle effect on the amphipathic helix of the peptide. In light of the minimum peptide/lipid ratio and the spectral linewidth, and the CSI-derived peptide structure, DOPG is proposed as a good compromise for structural studies of this membrane-associated peptide by solution NMR spectroscopy.

Original languageEnglish (US)
Pages (from-to)257-264
Number of pages8
Issue number2
Publication statusPublished - Jan 1 2004



  • Amphipathic helix
  • CMC
  • Escherichia coli
  • Lipid chain length
  • Micelles
  • NMR

ASJC Scopus subject areas

  • Spectroscopy

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