Conformation of gramicidin in relation to its ability to form bilayers with lysophosphatidylcholine

Journal Article · Tue Sep 20 00:00:00 EDT 1988 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00419a018· OSTI ID:6976605

Killian, J A; Urry, D W ^[1]

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1. Univ. of Alabama, Birmingham (USA)

The ability of gramicidin to induce bilayer formation in lysophosphatidylcholine (LPC) systems was investigated as a function of the conformation of the peptide. The conformation was varied by using different solvents to cosolubilize gramicidin and lipid. Using circular dichroism (CD), it was found that when codissolved in trifluoroethanol (TFE), after drying and subsequent hydration, gramicidin is mainly present in the single-stranded {beta}{sup 6.3}-helical configuration, whereas when using chloroform/methanol or ethanol as the solvent, it is proposed that the dominant conformation of gramicidin in the membrane is that of the double-stranded antiparallel dimer. Employing {sup 31}P NMR, the stoichiometry for bilayer formation was found to be 6 to 7 lipid molecules per gramicidin monomer, when samples were prepared from TFE, whereas a stoichiometry of 4 was found when chloroform/methanol or ethanol as the solvent. Upon heating the latter samples, a conversion was observed in the CD pattern toward that indicative of the {beta}{sup 6.3}-helical configuration. This change was accompanied by an increase in the extent of bilayer formation. Next, it was investigated whether the conformation of gramicidin and its ability to induce bilayer formation were dependent on the lipid acyl chain length. The results are discussed in terms of the possible mechanism of bilayer formation in dispersions of gramicidin and LPC in relation to the conformational behavior of the peptide.

• OSTI ID: 6976605
• Journal Information: Biochemistry; (USA), Vol. 27:19; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
MEMBRANES
STOICHIOMETRY
PHOSPHOLIPIDS
NUCLEAR MAGNETIC RESONANCE
CONFORMATIONAL CHANGES
DICHROISM
LIPIDS
NMR SPECTRA
PEPTIDES
SODIUM 23
ALKALI METAL ISOTOPES
ESTERS
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
PROTEINS
RESONANCE
SODIUM ISOTOPES
SPECTRA
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