[1] Univ Orleans, ICOA, UMR 6005, F-45067 Orleans, France
[2] Univ Grenoble 1, CERMAV, CNRS, F-38041 Grenoble, France
[3] European Synchrotron Radiat Facil, F-38043 Grenoble, France
[4] UJF, CNRS, Inst Univ France, Lab Virol Mol & Struct,FRE 2854, F-38042 Grenoble, France
[5] EMBL, Grenoble Outstn, F-38042 Grenoble, France