HdeA samples were prepared for NMR through dialysis into 50 mM citrate buffer at the desired pH, except for experiments recorded at pH 1.5, which utilized a buffer mixture of 50 mM sodium phosphate and 45 mM citrate. The pH meter was calibrated before each use and the buffers were regularly checked with a different pH probe and meter to ensure accuracy. NMR samples for peak and chemical shift analysis had protein concentrations in the range of 0.5 – 1.2 mM, while protein concentrations for relaxation experiments were 1.0 – 1.2 mM.
NMR data were obtained at 25 °C on an in-house Agilent DD2 600 MHz spectrometer with a triple resonance probe. For some experiments we also utilized a Varian VNMRS 800 MHz NMR spectrometer at NMRFAM (UW Madison) equipped with a cryogenic probe, or a Varian VNMRS 800 MHz NMR spectrometer with a room temperature probe at the University of Connecticut Health Sciences Center. All raw data were processed using NMRPipe/NMRDraw [33 , 34 (link)] and the resulting spectra were viewed and analyzed using NMRViewJ [35 , 36 (link)]. Most assignment and dynamics data have been deposited at BMRB, entry 50421. Data for “extra” peaks and CPMG are provided in thesupplemental materials .
NMR data were obtained at 25 °C on an in-house Agilent DD2 600 MHz spectrometer with a triple resonance probe. For some experiments we also utilized a Varian VNMRS 800 MHz NMR spectrometer at NMRFAM (UW Madison) equipped with a cryogenic probe, or a Varian VNMRS 800 MHz NMR spectrometer with a room temperature probe at the University of Connecticut Health Sciences Center. All raw data were processed using NMRPipe/NMRDraw [33 , 34 (link)] and the resulting spectra were viewed and analyzed using NMRViewJ [35 , 36 (link)]. Most assignment and dynamics data have been deposited at BMRB, entry 50421. Data for “extra” peaks and CPMG are provided in the