Physical Review Letters · 1999 · 40 citations · 16 references
Natural SciencesBiochemistryBiophysicsCrystal StructureMolecular BiophysicsStructural BiophysicsMembrane Phase BehaviorMembrane Protein InteractionsMembrane ProteinsMembrane ThermodynamicsPhase TransitionsProtein StructureMembrane InteractionsMembrane Protein ThermodynamicsPhase Transition TemperaturePhase Transitions In BiomembranesSynchrotron DiffractionSynchrotron X-ray DiffractionTemperature-dependent Phase TransitionsTwo-dimensional Arrays
We present a synchrotron x-ray diffraction study of melting in stacks of two-dimensional crystalline arrays of the membrane protein bacteriorhodopsin. Two distinct regimes have been found as a function of the intermembrane distance $d$. In the ``coupled'' regime for $d<250\AA{}$ the temperature $({T}_{m})$ of the melting transition decreases with increasing $d$, demonstrating the effect of the repulsive membrane interactions on the intramembrane protein ordering. For $d>250\AA{}$ a ``decoupled'' regime is found with higher ${T}_{m}^{*}$ independent of $d$. Below ${T}_{m}^{*}$ a solid-liquid-solid reentrant behavior is observed as $d$ is increased.
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