Application of pressure-modulated differential scanning calorimetry to the determination of relaxation kinetics of multilamellar lipid vesicles

Boehm, Kristian; Guddorf, Jessica; Hinz, Hans‐Jürgen

doi:10.1016/j.bpc.2006.06.004

Cited by 5 publications

(4 citation statements)

References 39 publications

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“…Pressure perturbation differential scanning calorimetry (PP‐DSC) is a new technique which permits determination of the thermal expansion coefficients of solute molecules in their dilute solution and thus estimates temperature‐induced changes of the partial volume of the solutes 1–4. A number of laboratories have used PP‐DSC for studying aqueous solutions of various low molecular weight compounds, lipids, and proteins 5–9. These studies led to an understanding that the thermal expansion coefficient carries information on hydration effects.…”

Section: Introductionmentioning

confidence: 99%

DNA hydration studied by pressure perturbation scanning microcalorimetry

2008

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Pressure perturbation differential scanning calorimetry was used to determine thermal expansion coefficients and thus temperature-induced volume changes of DNA duplexes differing in their GC/AT content. It was shown that the temperature-induced unfolding of the DNA duplexes proceeds with a significant increase of the thermal expansion coefficient and the partial volume of the DNA. Unusually, large temperature-induced changes in the partial volume were observed for an AT-rich dodecamer, a finding consistent with previous crystallographic studies showing the presence of highly ordered water molecules hydrating the minor groove of such duplexes. The data show that the density of this ordered water is substantially higher than that of the bulk water. This ordered water cannot, therefore, be equated to ice at normal pressures but it thermodynamically resembles ice formed at high pressures.

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Section: Introductionmentioning

confidence: 99%

DNA hydration studied by pressure perturbation scanning microcalorimetry

2008

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“…Transitions between different lipid phases may be induced by changing an external parameter such as temperature or pressure. [12][13][14][15][16][17][18][19][20][21][22] In most cases, these phase transitions are rather fast and hence require the application of fast relaxation techniques. 23 We have used the synchrotron X-ray diffraction technique to record the temporal evolution of the structural changes after induction of phase transitions in a canonical raft mixture by a pressure-jump across the corresponding phase boundaries.…”

Section: Introductionmentioning

confidence: 99%

“…Although the static structure and phase behavior of many lipid systems are now rather well established, a considerable lack of knowledge exists regarding the understanding of the kinetics and mechanisms of lipid phase transformations. Transitions between different lipid phases may be induced by changing an external parameter such as temperature or pressure. − In most cases, these phase transitions are rather fast and hence require the application of fast relaxation techniques …”

Section: Introductionmentioning

confidence: 99%

“…We have used the synchrotron X-ray diffraction technique to record the temporal evolution of the structural changes after induction of phase transitions in a canonical raft mixture by a pressure-jump across the corresponding phase boundaries. So far, pressure- and temperature-jump relaxation studies have been performed to study less complex lamellar phase transitions as well as lamellar-to-nonlamellar and intercubic lipid mesophase transitions only. − We used the pressure-jump relaxation technique which is sometimes advantageous over the temperature-jump approach: pressure propagates rapidly so that sample homogeneity is less of a problem, pressure-jumps can be performed bidirectionally, that is, in the pressurization and depressurization directions, and the amplitude of the pressure-jump can be easily and repeatedly varied to a level of high accuracy. To this end, we first explored the temperature- and pressure-dependent structure and phase behavior of a canonical lipid raft model system, the mixture DOPC/DPPC/cholesterol (1:2:1), using Fourier transform infrared (FTIR) spectroscopy and small-angle X-ray scattering (SAXS).…”

Section: Introductionmentioning

confidence: 99%

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X-ray Kinematography of Phase Transformations of Three-Component Lipid Mixtures: A Time-Resolved Synchrotron X-ray Scattering Study Using the Pressure-Jump Relaxation Technique

2008

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By using the pressure-jump relaxation technique in combination with time-resolved synchrotron small-angle X-ray diffraction (TRSAXS), the kinetics of lipid phase transformations of ternary lipid mixtures serving as model systems of heterogeneous raftlike membranes were investigated. To this end, we first established the temperature-pressure phase diagram of a model lipid raft mixture, 1,2-dioleoyl- sn-glycero-3-phosphatidylcholine (DOPC)/1,2-dipalmitoyl- sn-glycero-3-phosphatidylcholine (DPPC)/cholesterol (1:2:1), using Fourier transform infrared spectroscopy and SAXS, covering the pressure range from 1 bar to 10 kbar at temperatures in the range from 7 to 80 degrees C. We then studied the kinetics of interlamellar phase transitions of the ternary lipid system involving transitions from the fluidlike (liquid-disordered, l d) phase to the liquid-ordered (l o)/liquid-disordered (l d) two-phase coexistence region as well as between the two- and three-phase coexistence regions of the system, where also solid-ordered phases (s o) are involved. The phase transition from the all-fluid l d phase to the l o+l d two-phase coexistence region turns out to be rather rapid. Phases appear or disappear within the 25 ms time resolution of the technique, followed by a slow lattice relaxation process, which, depending on the pressure-jump amplitude, takes several seconds. Contrary to many one-component phospholipid phase transitions, the kinetics of the l d <--> l o+l d transition follows a similar time scale and mechanism for the pressurization and depressurization direction. A similar behavior is observed for the phase transition kinetics of the s o+l o+l d <--> l o+l d transformation and even for the s o+l o+l d <--> l d transformation, jumping across the l o+l d two-phase region. All transitions are fully reversible, and no intermediate states are populated. As indicated by the complex relaxation profiles observed, the overall rates observed seem to reflect the effect of coupling of various dynamical processes through the transformation, involving fast conformational changes in the sub-millisecond time regime and slow relaxation of the lattices growing, probably being largely controlled by the transport and redistribution of water into and in the new phases of the multilamellar vesicle assemblies.

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Pressure jump relaxation investigations of lipid membranes using FTIR spectroscopy

Schiewek

Blume

2008

Eur Biophys J

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The relaxation kinetics of aqueous lipid dispersions after a pressure jump (p-jump) were investigated using time-resolved FTIR spectroscopy. The methylene stretching vibrational band and the carbonyl band were analyzed to detect changes in conformational order of the hydrocarbon chains and to follow the degree of hydration of the head group, respectively. The kinetics of the transition was found to consist of multiple processes with relaxation constants from seconds down to milliseconds. Faster processes are also present, but could not be resolved by our instrument. This is the first investigation showing directly the time resolved change in chain order in lipid bilayers induced by a p-jump. The results obtained with this IR detection method support previous results that the change in chain order after a perturbation is a multi-step process with the initial molecular events occurring with time constants shorter than milliseconds.

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Application of pressure-modulated differential scanning calorimetry to the determination of relaxation kinetics of multilamellar lipid vesicles

Cited by 5 publications

References 39 publications

DNA hydration studied by pressure perturbation scanning microcalorimetry

DNA hydration studied by pressure perturbation scanning microcalorimetry

X-ray Kinematography of Phase Transformations of Three-Component Lipid Mixtures: A Time-Resolved Synchrotron X-ray Scattering Study Using the Pressure-Jump Relaxation Technique

Pressure jump relaxation investigations of lipid membranes using FTIR spectroscopy

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