The membrane interaction of amphiphilic model peptides affects phosphatidylserine headgroup and acyl chain order and dynamics. Application of the phospholipid headgroup electrometer concept to phosphatidylserine
- Univ. of Utrecht (Netherlands)
Deuterium nuclear magnetic resonance ({sup 2}H NMR) was used to study the interaction of amphiphilic model peptides with model membranes consisting of 1,2-dioleoyl-sn-glycero-3-phospho-L-serine deuterated either at the {beta}-position of the serine moiety ((2-{sup 2}H)DOPS) or at the 11-position of the acyl chains ((11,11-{sup 2}H{sub 2})DOPS). The peptides are derived from the sequences H-Ala-Met-Leu-Trp-Ala-OH and H-Arg-Met-Leu-Trp-Ala-OH and contain a positive charge of +1 or +2 at the amino terminus or one positive charge at each end of the molecule. Upon titration of dispersions of DOPS with the peptides, the divalent peptides show a similar extent of binding to the DOPS bilyers, which is larger than that of the single charged peptide. Under these conditions the values of the quadrupolar splitting of both (2-{sup 2}H)DOPS and (11,11-{sup 2}H{sub 2})DOPS are decreased, indicating that the peptides reduce the order of both the DOPS headgroup and the acyl chains. The extent of the decrease depends on the amount of peptide bound and on the position of the charged moieties in the peptide molecule. Titrations of DOPS with poly(L-lysine){sub 100}, which were included for reasons of comparison, reveal increased {Delta}v{sub q} values. When the peptide-lipid titrations are carried out without applying a freeze-thaw procedure to achieve full equilibration, two-component {sup 2}H NMR spectra occur. The apparently limited accessibility of the lipid to the peptides under these circumstances is discussed in relation to the ability of the peptides to exhibit transbilayer movement. {sup 2}H spin-lattice relaxation time T1 measurements demonstrate a decrease of the rates of motion of both headgroup and acyl chains of DOPS in the presence of the peptides.
- OSTI ID:
- 5398940
- Journal Information:
- Biochemistry; (United States), Vol. 30:4; ISSN 0006-2960
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CELL MEMBRANES
CONFIGURATION INTERACTION
LIPOPROTEINS
NUCLEAR MAGNETIC RESONANCE
SERINE
DEUTERIUM COMPOUNDS
NMR SPECTRA
PHOSPHOPROTEINS
AMINO ACIDS
CARBOXYLIC ACIDS
CELL CONSTITUENTS
HYDROGEN COMPOUNDS
HYDROXY ACIDS
LIPIDS
MAGNETIC RESONANCE
MEMBRANES
ORGANIC ACIDS
ORGANIC COMPOUNDS
PROTEINS
RESONANCE
SPECTRA
550201* - Biochemistry- Tracer Techniques