Studying Intrinsically Disordered Proteins under True In Vivo Conditions by Combined Cross‐Polarization and Carbonyl‐Detection NMR Spectroscopy

Under physiological conditions, studies of intrinsically disordered proteins (IDPs) by conventional NMR methods based on proton detection are severely limited by fast amide‐proton exchange with water. 13 C detection has been proposed as a solution to the exchange problem, but is hampered by low sensitivity. We propose a new pulse sequence combining proton–nitrogen cross‐polarization and carbonyl detection to record high‐resolution, high‐sensitivity NMR spectra of IDPs under physiological conditions. To demonstrate the efficacy of this approach, we recorded a high‐quality N–CO correlation spectrum of α‐synuclein in bacterial cells at 37 °C.