Raman and Fourier Transform Infrared Spectroscopic Studies of the Interaction between Glycophorin and Dimyristoylphosphatidylcholine

Mendelsohn, R.; Dluhy, Richard A.; Cameron, D.; Mantsch, Henry H.

doi:10.1016/s0006-3495(82)84611-0

Cited by 10 publications

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“…The values of R calculated from the spectra of Figure decreased from 1.36 to 1.06 when the temperature increased from 19.5 to 28 °C. The intermediate value ( R = 1.21) obtained at T = 21.5 °C confirms that the phase transition displays on a rather large temperature range as already observed on black films using infrared spectroscopy 11 as well as in multilayer dispersions using Raman spectroscopy. , It can be noted that the value of R in the gel phase is very close to the one we found for bulk polycrystalline DMPC at the same temperature. Concerning the L α phase, R has been found equal to 1.06, slightly higher than the one ( R = 1.0) found in both multilamellar vesicles 34 and lamellar phases .…”

Section: Resultssupporting

confidence: 87%

Raman Spectroscopy of Phospholipid Black Films

et al. 2000

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Single planar bilayers of DMPC free-standing in air (black films) have been studied by confocal micro Raman spectroscopy in the 600-4000 cm -1 spectral range. The DMPC vibrational bands are well-defined. This allows the derivation of two parameters associated with the packing and mobility and with the fluidity of the alkyl chains and to quantify the rigidity enhancement accompanying the L R liquid crystalline to gel phase transition (T m ) 24 °C). The intensity of the water band allows to evaluate the thickness of the interstitial aqueous core which is 22 ( 4 Å in the L R phase. This water band exhibits a spectral change relative to bulk liquid water which is significant of the confinement of water molecules in the aqueous core.

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Section: Resultssupporting

confidence: 87%

Raman Spectroscopy of Phospholipid Black Films

et al. 2000

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“…The frequency shifts in the asymmetric stretching mode indicate that melittin induces gauche to trans isomerization, i.e., acyl chain conformational ordering, of the DPPC and disordering of the DPPS monolayers. Similarly, changes in the bandwidth, considered to be primarily sensitive to acyl chain mobility (Mendelsohn et al, 1981), indicate decreased motional rates for DPPC and increased motional rates for the DPPS acyl chains upon melittin adsorption.…”

Section: Discussionmentioning

confidence: 99%

Infrared reflection-absorption of melittin interaction with phospholipid monolayers at the air/water interface

Flach

Prendergast

Mendelsohn

1996

Biophysical Journal

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The interaction of melittin with monolayers of 1,2-dipalmitoylphosphatidylcholine and 1,2-dipalmitoylphosphatidylserine has been investigated with infrared external reflection-absorption spectroscopy. Improved instrumentation permits determination of acyl chain conformation and peptide secondary structure in situ at the air/water interface. The IR frequency of the 1,2-dipalmitoylphosphatidylcholine antisymmetric acyl chain CH2 stretching vibration decreases by 1.3 cm-1 upon melittin insertion, consistent with acyl chain ordering, whereas the same vibrational mode increases by 0.5 cm-1 upon peptide interaction with the 1,2-dipalmitoylphosphatidylserine monolayer, indicative of chain disordering. Thus the peptide interacts quite differently with zwitterionic compared with negatively charged monolayer surfaces. Melittin in the monolayer adopted a secondary structure with an amide l(l') frequency (1635 cm-1) dramatically different from the alpha-helical motif (amide l frequency 1656 cm-1 in a dry or H2O hydrated environment, amide l' frequency 1645 cm-1 in an H-->D exchanged alpha-helix) assumed in bilayer or multibilayer environments. This work represents the first direct in situ spectroscopic indication that peptide secondary structure in lipid monolayers may differ from that in bilayers.

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“…Evidence for a new phase transition above Tm has been forwarded for osmotically stressed liposomes of DLPC and DMPC (Lis et al, 1982). There are some indications for a change in the conformation and/or organization of DMPC in the temperature range of 30-350C (Mendelsohn et al, 1981;Sankaram et al, 1992). To could arise from reduction of the steric pressure because of an increase in membrane free volume due to temperature-dependent increment in transgauche isomerization of the acyl chains, which then results in a gradual fading of the phase separation of PPDPC.…”

Section: Discussionmentioning

confidence: 99%

Poly(ethylene glycol)-induced and temperature-dependent phase separation in fluid binary phospholipid membranes

Lehtonen

Kinnunen

1995

Biophysical Journal

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Exclusion of the strongly hygroscopic polymer, poly(ethylene glycol) (PEG), from the surface of phosphatidylcholine liposomes results in an osmotic imbalance between the hydration layer of the liposome surface and the bulk polymer solution, thus causing a partial dehydration of the phospholipid polar headgroups. PEG (average molecular weight of 6000 and in concentrations ranging from 5 to 20%, w/w) was added to the outside of large unilamellar liposomes (LUVs). This leads to, in addition to the dehydration of the outer monolayer, an osmotically driven water outflow and shrinkage of liposomes. Under these conditions phase separation of the fluorescent lipid 1-palmitoyl-2[6-(pyren-1-yl)]decanoyl-sn-glycero-3-phosphocholine (PPDPC) embedded in various phosphatidylcholine matrices was observed, evident as an increase in the excimer-to-monomer fluorescence intensity ratio (IE/IM). Enhanced segregation of the fluorescent lipid was seen upon increasing and equal concentrations of PEG both inside and outside of the LUVs, revealing that osmotic gradient across the membrane is not required, and phase separation results from the dehydration of the lipid. Importantly, phase separation of PPDPC could be induced by PEG also in binary mixtures with 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), 1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine (SOPC), and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), for which temperature-induced phase segregation of the fluorescent lipid below Tm was otherwise not achieved. In the different lipid matrices the segregation of PPDPC caused by PEG was abolished above characteristic temperatures T0 well above their respective main phase transition temperatures Tm. For 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), DMPC, SOPC, and POPC, T0 was observed at approximately 50, 32, 24, and 20 degrees C, respectively. Notably, the observed phase separation of PPDPC cannot be accounted for the 1 degree C increase in Tm for DMPC or for the increase by 0.5 degrees C for DPPC observed in the presence of 20% (w/w) PEG. At a given PEG concentration maximal increase in IE/IM (correlating to the extent of segregation of PPDPC in the different lipid matrices) decreased in the sequence 1,2-dihexadecyl-sn-glycero-3-phosphocholine (DHPC) > DPPC > DMPC > SOPC > POPC, whereas no evidence for phase separation in 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) LUV was observed (Lehtonen and Kinnunen, 1994, Biophys. J. 66: 1981-1990). Our results indicate that PEG-induced dehydration of liposomal membranes provides the driving force for the segregation of the pyrene lipid. In brief, phase separation of PPDPC from the matrix lipid could be attributed to the diminishing effective size of the phosphatidylcholine polar headgroup resulting from its partial dehydration by PEG. This in turn would allow for enhanced van der Waals interactions between the acyl chains of the matrix lipid, which then caused the exclusion of PPDPC due to the perturbing bulky pyrene moiety. Phase separation in DMPC/PPDPC liposomes w...

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Raman and Fourier Transform Infrared Spectroscopic Studies of the Interaction between Glycophorin and Dimyristoylphosphatidylcholine

Cited by 10 publications

References 0 publications

Raman Spectroscopy of Phospholipid Black Films

Raman Spectroscopy of Phospholipid Black Films

Infrared reflection-absorption of melittin interaction with phospholipid monolayers at the air/water interface

Poly(ethylene glycol)-induced and temperature-dependent phase separation in fluid binary phospholipid membranes

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