[1] Univ Bordeaux, ARNA Lab, F-33000 Bordeaux, France
[2] INSERM, ARNA Lab, U869, F-33000 Bordeaux, France
[3] Univ Bordeaux, CNRS, Ctr Resonance Magnet Syst Biol, UMR 5536, F-33076 Bordeaux, France
[4] Univ Bordeaux, Inst Chim Matiere Condensee Bordeaux, ICMCB UPR CNRS 9048, F-33608 Pessac, France