Phase transitions of the purple membranes of Halobacterium halobium.
Purple membranes of Halobacterium halobium were studied by differential scanning calorimetry. No transition was detected at temperatures below 70 degrees C. A small endothermic transition was seen at about 80 degrees C and a larger one at 100 degrees C. The larger transition is the irreversible denaturation of bacteriorhodopsin. The smaller transition is accompanied by a change in the visible absorption spectrum and is believed to be reversible, involving a cooperative change in crystalline structure of the membrane.
D001436:Bacteriorhodopsins; D002151:Calorimetry; D002338:Carotenoids; D006217:Halobacterium / Q000648:ultrastructure; D008563:Membrane Lipids; D008565:Membrane Proteins; D011489:Protein Denaturation; D013053:Spectrophotometry; D013696:Temperature; D013816:Thermodynamics
D008563:Membrane Lipids; D008565:Membrane Proteins; D002338:Carotenoids; D001436:Bacteriorhodopsins