NMR spectra were acquired at 27 °C on Bruker Avance 800 and DRX500 spectrometers, equipped with triple-resonance (1H/15N/13C) cryoprobes. All data were acquired using a sample containing 2 mM 15N/13C-labeled protein, 25 mM sodium phosphate, pH 6.0, 10 mM sodium chloride, and 10% 2H2O and comprised the following: 2D: [15N–1H] heteronuclear single quantum coherence (HSQC), [13C–1H] HSQC covering full 13C spectral width, constant-time [13C–1H] HSQC covering only aliphatic 13C region, [1H–1H] NOE spectroscopy (NOESY) experiments (τm = 50, 100, and 150 ms), [1H–1H] NOESY experiments filtered to remove 15N-coupled signals in F2 (τm = 50 and 150 ms); 3D data sets: CBCANH, CBCACONH, HBHANH, HBHACONH, [1H–13C–1H] HCCH–total correlated spectroscopy, [1H–13C–1H] HCCH–correlated spectroscopy, 15N NOESY–HSQC (τm = 50 and 150 ms), and 13C NOESY–HSQC (τm = 50 and 150 ms), with separate data sets acquired for 13C aliphatic and aromatic spectral regions. 1H, 15N, and 13C chemical shifts were calibrated using sodium 3,3,3-trimethylsilylpropionate as external 1H reference.39