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Formation of Supported Lipid Bilayer Membranes on SiO2 from Proteoliposomes Containing Transmembrane Proteins

Annette Graneli ; Jan Rydström ; Bengt Kasemo (Institutionen för teknisk fysik) ; Fredrik Höök (Institutionen för teknisk fysik)
Langmuir Vol. 19 (2003), p. 842-850.
[Artikel, refereegranskad vetenskaplig]

We report the preparation of protein-containing supported phospholipid bilayers (SPBs) on silica (SiO2). The bilayers are formed from small proteoliposomes, which convert to an SPB when the liposomes adsorb on the surface. The kinetics of this conversion process was followed in real time, using the quartz crystal microbalance with dissipation monitoring (QCM-D) and surface plasmon resonance (SPR) techniques. The proteoliposomes were prepared by reconstitution of two different proteins into small unilamellar liposomes (diameter ~ 26 nm), creating proteoliposomes with diameters ranging from ca. 50 to 85 nm, depending on protein concentration. The two proteins were proton translocating nicotinamide nucleotide transhydrogenase (TH) from Escherichia coli and gramicidin A (GrA) from Bacillus brevis. The SPB formation process was measured and compared for different protein situations in the liposomes: (i) with the intact TH in the proteoliposomes, (ii) after removal of the water-exposed, hydrophilic domains of TH, and (iii) with GrA-containing proteoliposomes (with no water-soluble domains). In the latter two cases qualitatively similar kinetics were observed as with pure (i.e., without proteins) liposomes. In contrast, the water-exposed hydrophilic domains on TH are found to partially hamper the SPB formation process leaving fractions of nonruptured proteoliposomes on the surface. The latter effect becomes stronger with increasing protein/lipid ratio in the proteoliposomes. A comparison was made between activity measurements of TH-containing proteoliposomes in solution and TH-containing SPBs. The latter results support the conclusions from the QCM-D and SPR measurements.

Denna post skapades 2008-03-10. Senast ändrad 2014-01-13.
CPL Pubid: 69070


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Institutionen för kemi (2001-2011)
Institutionen för teknisk fysik (1900-2015)



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