NMR Spectroscopy of Thylakoid Membranes

³¹P-NMR measurements were performed as described earlier^{29 (link)}. In detail, spectra were recorded on DD2 600 MHz NMR spectrometer (Agilent) using a OneNMR probe and Avance Neo 600 MHz NMR spectrometer (Bruker) using a BBFO probe, both tuned at the resonance frequency of the ³¹P nucleus, with 5 mm outer diameter tubes containing about 1.2 ml thylakoid suspension at a Chl content of about 8–10 mg/ml. As tested earlier, at this concentration, no magnetic orientation of the membranes occurs^{27 (link)}. The temperature was controlled within 0.1 °C; spectra were recorded using a 40°rf pulse, an interpulse time of 0.5 s and no ¹H-decoupling. ³¹P chemical shifts are reported relative to 85% H₃PO₄ in water (δP = 0 ppm) used as an external reference. Spectral deconvolutions were performed by using the DMfit software^{70 (link)}.