This title appears in the Scientific Report :
2008
Please use the identifier:
http://dx.doi.org/10.1073/pnas.0802289105 in citations.
Resolving voltage-dependent structural changes of a membrane photoreceptor by surface-enhanced IR difference spectroscopy
Resolving voltage-dependent structural changes of a membrane photoreceptor by surface-enhanced IR difference spectroscopy
Membrane proteins are molecular machines that transport ions, solutes, or information across the cell membrane. Electrophysiological techniques have unraveled many functional aspects of ion channels but suffer from the lack of structural sensitivity. Here, we present spectroelectrochemical data on v...
Saved in:
Personal Name(s): | Jiang, X. |
---|---|
Zaitseva, E. / Schmidt, M. / Siebert, F. / Engelhard, M. / Schlesinger, R. / Ataka, K. / Vogel, R. / Heberle, J. | |
Contributing Institute: |
Molekulare Biophysik; INB-2 |
Published in: | Proceedings of the National Academy of Sciences of the United States of America, 105 (2008) S. 12113 - 12117 |
Imprint: |
Washington, DC
Academy
2008
|
Physical Description: |
12113 - 12117 |
DOI: |
10.1073/pnas.0802289105 |
PubMed ID: |
18719097 |
Document Type: |
Journal Article |
Research Program: |
Funktion und Dysfunktion des Nervensystems |
Series Title: |
Proceedings of the National Academy of Sciences of the United States of America
105 |
Subject (ZB): | |
Publikationsportal JuSER |
Membrane proteins are molecular machines that transport ions, solutes, or information across the cell membrane. Electrophysiological techniques have unraveled many functional aspects of ion channels but suffer from the lack of structural sensitivity. Here, we present spectroelectrochemical data on vibrational changes of membrane proteins derived from a single monolayer. For the seven-helical transmembrane protein sensory rhodopsin II, structural changes of the protein backbone and the retinal cofactor as well as single ion transfer events are resolved by surface-enhanced IR difference absorption spectroscopy (SEIDAS). Angular changes of bonds versus the membrane normal have been determined because SEIDAS monitors only those vibrations whose dipole moment are oriented perpendicular to the solid surface. The application of negative membrane potentials (DeltaV = -0.3 V) leads to the selective halt of the light-induced proton transfer at the stage of D75, the counter ion of the retinal Schiff base. It is inferred that the voltage raises the energy barrier of this particular proton-transfer reaction, rendering the energy deposited in the retinal by light excitation insufficient for charge transfer to occur. The other structural rearrangements that accompany light-induced activity of the membrane protein, are essentially unaffected by the transmembrane electric field. Our results demonstrate that SEIDAS is a generic approach to study processes that depend on the membrane potential, like those in voltage-gated ion channels and transporters, to elucidate the mechanism of ion transfer with unprecedented spatial sensitivity and temporal resolution. |