Use of Isotope-Edited FTIR to Derive a Backbone Structure of a Transmembrane Protein.
Solving structures of membrane proteins has always been a formidable challenge, yet even upon success, the results are normally obtained in a mimetic environment that can be substantially different from a biological membrane. Herein, we use noninvasive isotope-edited FTIR spectroscopy to derive a structural model for the SARS coronavirus E protein transmembrane domain in lipid bilayers. Molecular-dynamics-based structural refinement, incorporating the IR-derived orientational restraints points to the formation of a helical hairpin structure. Disulfide cross-linking and X-ray reflectivity depth profiling provide independent support of the results. The unusually short helical hairpin structure of the protein might explain its ability to deform bilayers and is reminiscent of other peptides with membrane disrupting functionalities. Taken together, we show that isotope-edited FTIR is a powerful tool to analyze small membrane proteins in their native environment, enabling us to relate the unusual structure of the SARS E protein to its function.
†Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmund J. Safra Campus, Jerusalem 91904, Israel.
Joshua
J
Manor
†Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmund J. Safra Campus, Jerusalem 91904, Israel.
Eyal
E
Arbely
‡Institut für Röntgenphysik, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, Göttingen 37077 Germany.
Andrè
A
Beerlink
§Faculty of Science and Technology, Al-Quds University, Abu Dis, Palestinian National Authority.
Mutaz
M
Akkawi
†Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmund J. Safra Campus, Jerusalem 91904, Israel.
Isaiah T
IT
Arkin
E protein; SARS coronavirus; dichroism; orientational constraint; protein refinement