Supporting reconstituted membrane structure

FIG. 14 Schematic illustration of an archaeal cell envelope structure (a) composed of the cytoplasmic membrane with associated and integral membrane proteins and an S-layer lattice, integrated into the cytoplasmic membrane, (b) Using this supramolecular construction principle, biomimetic membranes can be generated. The cytoplasmic membrane is replaced by a phospholipid or tetraether hpid monolayer, and bacterial S-layer proteins are crystallized to form a coherent lattice on the lipid film. Subsequently, integral model membrane proteins can be reconstituted in the composite S-layer-supported lipid membrane. (Modified from Ref. 124.)... 

The hexane-extracted particles that still retained one Q per P700 retained 81 % of the NADP -reduction activity ofthe unextracted control. In contrast, particles extracted with hexane-0.3% methanol had all the OQ removed and the NADP -reduction activity was completely lost. The NADP -reduction activity of the hexane/methanol-extracted particles could be reactivated by readdition of exogenous but only when the hexane extract was also added back. Exogenous OQ alone, even at a rather high concentration, could not reactivate NADP photoreduction and the hexane extract alone was also not effective, presumably because of its low Q content. The nature ofthe component in the hexane extract that contributes to reconstitution is as yet unknown. As the hexane extract contains OQ,chlorophylls,carotenoids,lipidsand other nonpolar molecules, some critical component is probably needed to ensure the correct membrane structure for binding ferredoxin and/or Fd-NADP -reductase. This conclusion is supported by the fact that activity of prior terminal acceptors such as the iron-sulfur centers do not require the hexane extract. 

An all plastic tank may be used for a chemical process such as the reconstituting of spent hydrochloric acid. However, at higher temperatures, the acid will attack the plastic sufficiently rapidly to make its use uneconomical unless a masonry lining is placed inside the plastic to insulate the interior—to bring the temperature on the face of the plastic down to an acceptable level. The plastic, then, functions as supporting structure and membrane, and the three necessary functions are supplied by two materials. 

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