Antoine Royant,^1,2 Karl Edman,³ Thomas Ursby,⁴ Eva Pebay-Peyroula,¹ EhudM. Landau,^5,* Richard Neutze<sup>3,**

1</sup>aInstitut de Biologie Structurale, UMR 5075-CEA-CNRS-Université Joseph Fourier, Grenoble, France;
²bEuropean Synchrotron Radiation Facility, Grenoble, France
³cDepartment of Molecular Biotechnology, Chalmers University of Technology, Gothenburg, Sweden
⁴dMAX-Lab, Lund University, Lund, Sweden
⁵eMembrane Protein Laboratory, Department of Physiology and Biophysics, and Sealy Center for Structur

^**To whom correspondence should be addressed at (EML): Membrane Protein Laboratory, Department of Physiology and Biophysics, and Sealy Center for Structural Biology, The University of Texas Medical Branch, 310 University Boulevard, Galveston, TX 77554-0437, USA. Fax: 409-772-1301; emlandau@utmb.edu
^***To whom correspondence should be addressed at (RN): Department of Molecular Biotechnology, Chalmers University of Technology, P.O. Box 462, S-40530, Gothenburg, Sweden. Fax: 46-31-773-3233; neutze@molbiotech.chalmers.se