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Lysine-modified valinomycin as a biosensor

Max-Planck-Institut für Polymerforschung Max Planck Institute for Polymer Research. Lysine-modified valinomycin as a biosensor. Julia Braunagel. Ile de Berder 28.08.2007. Outline. Membrane model systems 2. Tethered bilayer lipid membranes 3. Cornell´s biosensor

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Lysine-modified valinomycin as a biosensor

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  1. Max-Planck-Institut für Polymerforschung Max Planck Institute for Polymer Research Lysine-modified valinomycin as a biosensor Julia Braunagel Ile de Berder 28.08.2007

  2. Outline • Membrane model systems • 2. Tethered bilayer lipid membranes • 3. Cornell´s biosensor • 4. Valinomycin as a biosensor

  3. Model systems Vesicles sBLM‘s BLM‘s tBLM‘s Picture: F. Giess

  4. Ion Channel Lipid Bi-Layer Tether (Spacerunit) Substrate Tethered bilayer lipid membranes, tBLMs • Key features of a suitable system: • Insulating • Robust • Stable • Fluid • Homogeneous Cornell et al., Nature, 387 (1997) p. 580 Terrettaz et al., Angew. Chem. 40 (2001) p.1740 Schiller et al.,Angew. Chem.,42(2003) p.208 Naumann et al, Langmuir, 19(2003) p. 5435 Atanasov et al., Biophy. J. 89 (2005) p. 1780 Köper et al, Advances in Planar Lipid Bilayers (2006)

  5. Preparation of a tBLM

  6. Spacer Phyt Anchor n DPG A generic tBLM system Lipid n = 4, 6, 8, 12, 14 X = Lipoic Acid, SH: Au, Ag, Cu,Fe, Ni, Pt, GaAs,Hg X = SiY: silicon oxide; (Y = Cl, OCH3, OC2H5) V. Atanasov, et al. Bioconjugated Chemistry 17, 631-637 (2006)

  7. DPTL, 2,3-di-O-phytanyl-sn-glycerol-1-tetraethylene glycol-D,L-α-lipoic acid ester Properties: - R >10MW cm2 - C < 1µF cm-2 - Semi-Fluid - Robust - Stable - Reproducible Schiller et al., Angew. Chem., 42(2003) p.208 Patent : DE 102 22 588.5; EP 03 011 554.7; US-2004-0023304-A1 Available at diverchim.com

  8. Incorporation of Gramicidin ion-channel Cations e.g. K+ tBLM with Gramicidin Gold

  9. Cornell´s biosensor Streptavidin Biotin Tethered membrane-spanning lipids B.A. Cornell et al., 1997, Nature 387: 580-583

  10. Valinomycin based biosensor

  11. Valinomycin based biosensor • Advantages: • easy synthesis on a multi-milligram scale • very specific to potassium • no tethered membrane-spanning lipids necessary • no anchorage on the surface necessary

  12. Valinomycin based biosensor

  13. Valinomycin Ester carbonyls are turned inwards, forming 6 ion-dipole bonds with a centrally situated cation. Modification on the backbone of the dodecadepsipeptide leads to the lost of complexing properties. Exchange in the amino acid sequence Shemyakin et al., 1974, FEBS Letters44: 1-21

  14. Lysine-modified Valinomycin Exchange of one L-Valin by an L-Lysine possibility to bind e.g. biotin to valinomycin The synthesis is described on my poster.

  15. Acknowledgment Prof. W. Knoll Dr. I. Köper Dr. V. Atanasov Thank you for your attention!

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