Details
| Original language | English |
|---|---|
| Pages (from-to) | 2522-31 |
| Number of pages | 10 |
| Journal | Biophysical journal |
| Volume | 87 |
| Issue number | 4 |
| Publication status | Published - Oct 2004 |
Abstract
Atomic force microscopy at high temperature resolution (DeltaT < or approximately 0.1 K) provided a quantitative structural calorimetry of the transition from the fluid (Lalpha)- to the gel (Pbeta')-phase of supported dimyristoylphosphatidylcholine bilayers. Besides a determination of the main transition temperature (T0) and the van't Hoff transition enthalpy (DeltaHvH), the structural analysis in the nm-scale at T close to T0 of the ripple phase allowed an experimental estimation of the area of cooperative units from small lipid domains. Thereby, the corresponding transition enthalpy (DeltaH) of single molecules could be determined. The lipid organization and the corresponding parameters T0 and DeltaHvH (DeltaH) were modulated by heptanol or external Ca2+ and compared with physiological findings. The size of the cooperative unit was not significantly affected by the presence of 1 mM heptanol. The observed linear relationship of DeltaHvH and T0 was discussed in terms of a change in heat capacity.
Keywords
- Calcium/chemistry, Calorimetry/methods, Dimyristoylphosphatidylcholine/chemistry, Heptanol/chemistry, Image Interpretation, Computer-Assisted/methods, Lipid Bilayers/chemistry, Membrane Fluidity, Membranes, Artificial, Microscopy, Atomic Force/methods, Molecular Conformation, Phase Transition, Surface Properties, Temperature, Transition Temperature
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In: Biophysical journal, Vol. 87, No. 4, 10.2004, p. 2522-31.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Structural calorimetry of main transition of supported DMPC bilayers by temperature-controlled AFM
AU - Enders, O
AU - Ngezahayo, A
AU - Wiechmann, M
AU - Leisten, F
AU - Kolb, H-A
N1 - Funding information: We gratefully acknowledge support from the “Forschungsfond” of the University Hannover.
PY - 2004/10
Y1 - 2004/10
N2 - Atomic force microscopy at high temperature resolution (DeltaT < or approximately 0.1 K) provided a quantitative structural calorimetry of the transition from the fluid (Lalpha)- to the gel (Pbeta')-phase of supported dimyristoylphosphatidylcholine bilayers. Besides a determination of the main transition temperature (T0) and the van't Hoff transition enthalpy (DeltaHvH), the structural analysis in the nm-scale at T close to T0 of the ripple phase allowed an experimental estimation of the area of cooperative units from small lipid domains. Thereby, the corresponding transition enthalpy (DeltaH) of single molecules could be determined. The lipid organization and the corresponding parameters T0 and DeltaHvH (DeltaH) were modulated by heptanol or external Ca2+ and compared with physiological findings. The size of the cooperative unit was not significantly affected by the presence of 1 mM heptanol. The observed linear relationship of DeltaHvH and T0 was discussed in terms of a change in heat capacity.
AB - Atomic force microscopy at high temperature resolution (DeltaT < or approximately 0.1 K) provided a quantitative structural calorimetry of the transition from the fluid (Lalpha)- to the gel (Pbeta')-phase of supported dimyristoylphosphatidylcholine bilayers. Besides a determination of the main transition temperature (T0) and the van't Hoff transition enthalpy (DeltaHvH), the structural analysis in the nm-scale at T close to T0 of the ripple phase allowed an experimental estimation of the area of cooperative units from small lipid domains. Thereby, the corresponding transition enthalpy (DeltaH) of single molecules could be determined. The lipid organization and the corresponding parameters T0 and DeltaHvH (DeltaH) were modulated by heptanol or external Ca2+ and compared with physiological findings. The size of the cooperative unit was not significantly affected by the presence of 1 mM heptanol. The observed linear relationship of DeltaHvH and T0 was discussed in terms of a change in heat capacity.
KW - Calcium/chemistry
KW - Calorimetry/methods
KW - Dimyristoylphosphatidylcholine/chemistry
KW - Heptanol/chemistry
KW - Image Interpretation, Computer-Assisted/methods
KW - Lipid Bilayers/chemistry
KW - Membrane Fluidity
KW - Membranes, Artificial
KW - Microscopy, Atomic Force/methods
KW - Molecular Conformation
KW - Phase Transition
KW - Surface Properties
KW - Temperature
KW - Transition Temperature
U2 - 10.1529/biophysj.104.040105
DO - 10.1529/biophysj.104.040105
M3 - Article
C2 - 15454447
VL - 87
SP - 2522
EP - 2531
JO - Biophysical journal
JF - Biophysical journal
SN - 0006-3495
IS - 4
ER -