IMS Research Center of Integrative Molecular Systems (CIMoS)


The 10th CIMoS Seminar
Novel IR spectroscopies to study biological membranes and membrane proteins

The 10th CIMoS Seminar <br>Novel IR spectroscopies to study biological membranes and membrane proteins


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.


  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)

date CanceledOct 14, 2014 (Tue) 10:30-12:00
Place 201 Seminar Room, Main Office Building of IMS
Title Novel IR spectroscopies to study biological membranes and membrane proteins
Speaker Prof. Joachim Heberle
(Free University of Berlin)