title: Utilizing adsorbed proteoliposomes trapped in a non-ruptured state on SiO2 for amplified detection of membrane proteins.
abstract: The quartz crystal microbalance with dissipation (QCM-D) technique was used to monitor the formation of supported phospholipid bilayers (SPBs) on SiO2 using proteoliposomes with reconstituted proton translocating nicotinamide nucleotide transhydrogenase (TH). Exposure of the surface to such proteoliposomes creates a lipid film composed of a mixture of proteolipid bilayers and adsorbed non-ruptured proteoliposomes, where the fraction of the latter is reduced if the TH-liposomes are pretreated with trypsin to remove the water soluble domains of TH [Langmuir 19 (2003) 842]. In the present work, the latter study is complemented by investigating the influence of trypsin treatment of the mixed adlayer (proteolipid bilayer + non-ruptured proteoliposomes) after adsorption on the surface. This demonstrates how trypsin-cleavage induced rupture of adsorbed TH-liposomes can be utilized to detect the presence of less than 0.04 pmol/cm2 of immobilized TH.
authors.affiliation: Department of Chemical Physics, Applied Physics, Chalmers, Fysikgränd 3, S-41296 Gothenburg, Sweden. annette.graneli@fy.chalmers.se
authors.forename: Annette
authors.initials: A
authors.lastname: Granéli
authors.forename: Jan
authors.initials: J
authors.lastname: Rydström
authors.forename: Bengt
authors.initials: B
authors.lastname: Kasemo
authors.forename: Fredrik
authors.initials: F
authors.lastname: Höök
mesh_terms: D000327:Adsorption; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D008081:Liposomes / Q000032:analysis* / Q000737:chemistry; D008565:Membrane Proteins / Q000032:analysis* / Q000737:chemistry; D008832:Microchemistry / Q000295:instrumentation / Q000379:methods; D009250:NADP Transhydrogenases / Q000032:analysis* / Q000737:chemistry; D017494:Proton Pumps / Q000032:analysis / Q000737:chemistry; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012822:Silicon Dioxide / Q000737:chemistry*; D014357:Trypsin / Q000737:chemistry
chemical_list: D020099:Coated Materials, Biocompatible; D008081:Liposomes; D008565:Membrane Proteins; D017494:Proton Pumps; D012822:Silicon Dioxide; D009250:NADP Transhydrogenases; D014357:Trypsin