大学共同利用機関法人 自然科学研究機構 分子科学研究所 協奏分子システム研究センター CIMoS

セミナー・シンポジウム

第10回CIMoSセミナー
Novel IR spectroscopies to study biological membranes and membrane proteins

第10回CIMoSセミナー<br>Novel IR spectroscopies to study biological membranes and membrane proteins

Canceled

Joachim Heberle

Freie Universität Berlin, Experimental Molecular Biophysics, Arnimallee 14, 14195 Berlin

Membrane proteins are the target of more than 50% of all drugs and are encoded by about 30% of the human genome. Electrophysiological techniques, like patch-clamp, unravelled many functional aspects of membrane proteins but suffer from structural sensitivity. We have developed Surface Enhanced Infrared Difference Absorption Spectroscopy (SEIDAS) to probe potential-induced structural changes of a protein on the level of a monolayer (see 1 for a recent review). A novel concept is introduced to incorporate membrane proteins into solid supported lipid bilayers in an orientated manner via the affinity of the His-tag to the Ni-NTA terminated gold surface. General applicability of the methodological approach is shown by tethering photosystem II to the gold surface. In conjunction with hydrogenase, the basis is set towards a biomimetic system for H2-production. FTIR difference spectra of a monolayer of sensory rhodopsin II were recorded under voltage-clamp conditions. This approach opens an avenue towards mechanistic studies of voltage-gated ion channels with unprecedented structural and temporal sensitivity. Finally, scanning near-field IR micrososcopy will be introduced and applied to study the structure of biomembranes2.

Vibrational spectroscopic studies on the novel light-gated channelrhodopsin-2 (ChR2) will be presented. ChR2 represents a versatile tool in the new field of optogenetics where physiological reactions are controlled by light. We have followed the structural changes of ChR2 by static and time-resolved FT-IR spectroscopy and identified internal proton transfer reactions involving aspartate and glutamate residues3. As the resolved protonation changes transiently alter the electrostatics and H-bonding networks within the protein, we infer that they represent the missing mechanistic link between retinal photo-isomerization and channel gating.

References:

  1. Ataka, K., Stripp, S., and Heberle, J. Biochim. Biophys. Acta 1828, 2283-93 (2013)
  2. Amenabar, I, Poly, S, Nuansing, W, Hubrich, EH, Govyadinov, A, Huth, F, Krutokhvostov, R, Zhang, L, Knez, M, Heberle, J, Bittner, A, Hillenbrand, R. Nature Commun. 2013 Dec 4;4:2890. doi: 10.1038/ncomms3890. (2013)
  3. Lórenz-Fonfría, V.A., Resler, T., Krause, N., Nack, M., Gossing, M., Fischer von Mollard, G., Bamann, C., Bamberg, E., Schlesinger, R., and Heberle, J. Proc. Natl. Acad. Sci USA 110 (14), E1273-E1281 (2013)

日時 Canceled(2014年10月14日(火) 10:30~12:00)
場所 分子科学研究所 研究棟201号室
題目 Novel IR spectroscopies to study biological membranes and membrane proteins
講演者 Joachim Heberle 教授 (ベルリン自由大学)

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