Comparison of lipid/gramicidin dispersions and cocrystals by Raman scattering

Kurt W. Short, B. A. Wallace, Richard A. Myers, Stephen P A Fodor, A. Dunker

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

Gramicidin crystals, dimyristoylphosphatidylcholine (DMPC)/gramicidin dispersions, and DMPC/gramicidin cocrystals were examined by Raman scattering to determine lipid/gramicidin stoichiometries and lipid organization. Calibrations of the choline (716-cm-1) and tryptophan (756-cm-1) peaks indicate that the cocrystals contain two lipids for each gramicidin monomer, a result confirmed by chemical analyses of washed crystals. In dispersions with high lipid/gramicidin ratios (e.g., 25:1), the lipid is ordered but becomes increasingly disordered as the gramicidin content is increased. Paradoxically, the DMPC/gramicidin cocrystals have highly ordered lipids that possibly contain no gauche bonds at all, despite their low lipid/gramicidin ratio. In addition, the polypeptide amide I peak position near 1670 cm-1 is found to be independent of the lipid/gramicidin ratio in the complexes and may indicate a β-helix-type secondary structure at all ratios. However, the amide I peak broadens significantly at low lipid/gramicidin ratios and broadens still further in the cocrystals, suggesting that protein-protein interactions may induce band-broadening distortions of the polypeptide structure.

Original languageEnglish (US)
Pages (from-to)557-562
Number of pages6
JournalBiochemistry
Volume26
Issue number2
StatePublished - 1987
Externally publishedYes

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Gramicidin
Raman Spectrum Analysis
Dispersions
Raman scattering
Lipids
Dimyristoylphosphatidylcholine
Amides
Peptides
Crystals
Choline
Tryptophan
Stoichiometry
Calibration
Proteins
Monomers

ASJC Scopus subject areas

  • Biochemistry

Cite this

Short, K. W., Wallace, B. A., Myers, R. A., Fodor, S. P. A., & Dunker, A. (1987). Comparison of lipid/gramicidin dispersions and cocrystals by Raman scattering. Biochemistry, 26(2), 557-562.

Comparison of lipid/gramicidin dispersions and cocrystals by Raman scattering. / Short, Kurt W.; Wallace, B. A.; Myers, Richard A.; Fodor, Stephen P A; Dunker, A.

In: Biochemistry, Vol. 26, No. 2, 1987, p. 557-562.

Research output: Contribution to journalArticle

Short, KW, Wallace, BA, Myers, RA, Fodor, SPA & Dunker, A 1987, 'Comparison of lipid/gramicidin dispersions and cocrystals by Raman scattering', Biochemistry, vol. 26, no. 2, pp. 557-562.
Short KW, Wallace BA, Myers RA, Fodor SPA, Dunker A. Comparison of lipid/gramicidin dispersions and cocrystals by Raman scattering. Biochemistry. 1987;26(2):557-562.
Short, Kurt W. ; Wallace, B. A. ; Myers, Richard A. ; Fodor, Stephen P A ; Dunker, A. / Comparison of lipid/gramicidin dispersions and cocrystals by Raman scattering. In: Biochemistry. 1987 ; Vol. 26, No. 2. pp. 557-562.
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