Raman spectroscopy of supported lipid bilayers and membrane proteins
<p>Off-resonance unenhanced total internal reflection (<em>TIR</em>) Raman Spectroscopy was explored to investigate supported single lipid bilayers with incorporated membrane peptides/proteins at water/solid interface.</p> <p>A model membrane was formed on a planar sup...
| Հիմնական հեղինակներ: | , |
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| Այլ հեղինակներ: | |
| Ձևաչափ: | Թեզիս |
| Լեզու: | English |
| Հրապարակվել է: |
2005
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| Խորագրեր: |
| Ամփոփում: | <p>Off-resonance unenhanced total internal reflection (<em>TIR</em>) Raman Spectroscopy was explored to investigate supported single lipid bilayers with incorporated membrane peptides/proteins at water/solid interface.</p> <p>A model membrane was formed on a planar supported lipid layer (<em>pslb</em>) by the fusion of the reconstituted small unilamellar vesicles (<em>SUV</em>s), and the intensity of bilayer was confirmed by a comparison of Raman spectral intensity in the C-H stretching modes with C<sub>16</sub>TAB. With prominent Raman sensitivity attained, we studied the 2-<em>D</em> phase transition of <em>DMPC</em> and <em>DPPC pslbs</em> and the temperature-dependent polarised spectra revealed a broad transition range of ca. 10 °C commencing at the calorimetric phase transition temperature.</p> <p>We applied polarised <em>TIR</em>-Raman Spectroscopy to <em>pslbs</em> formed by <em>DMPC SUV</em>s reconstituted with a model membrane-spanning peptide gramicidin D. A preferential channel structure formed by dissolution of trifluoroethanol could be probed by polarised Raman Spectroscopy qualitatively showing an antiparallel β-sheet conformation (different from "standard" one) and our Raman spectra by correlation with <em>NMR</em> and <em>CD</em> data confirmed single-stranded π<sup>6.3</sup> β-helical channel structure in the single bilayer. We also studied the membrane-penetrating peptide indolicidin in the presence of <em>DMPC pslb</em> over the chain melting temperature and a β-turn structure was dominantly observed concomitant with membrane perturbation.</p> <p>Dynamic adsorption of <em>DPPC</em> to form <em>pslb</em> from a micellar solution of <em>n</em>-dodecyl-β- <sub>D</sub>-maltoside could be examined with high sensitivity of every 1-<em>min</em> acquisition. Finally we used polarised <em>TIR</em>-Raman scattering to porcine pancreatic phospholipase A<sub>2</sub> hydrolytic activity on <em>DPPC pslbs</em> and revealed lipid-active conformation different from that of the enzyme alone.</p> |
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