Aviii hd 600 mhz

All NMR spectra of dsRBD and tRNA were measured at 303 K on a Bruker AVIII HD 600 MHz equipped with a cryoprobe in a buffer containing 25 mM sodium phosphate pH 6.5, 20 mM sodium chloride, 10 mM dithiothreitol (DTT) and 10% (v/v) D₂O. The data were processed using TOPSPIN 3.5 (Bruker) and analyzed with Sparky (www.cgl.ucsf.edu/home/sparky/). The backbone resonances of dsRBD (residues 337–450) were assigned using 2D (¹H,¹⁵N)-HSQC, 3D HNCA, 3D HNCACB, 3D CBCA(CO)NH, 3D HNCO and 3D NOESY-(¹H,¹⁵N)-HSQC. For titration experiments, 0.35 mM of ¹⁵N-labeled dsRBD were mixed with increasing amount of unlabeled tRNA^Lys3 up to 1 molar equivalent and 2D (¹H,¹⁵N)-HSQC were recorded at each step. Similarly, the titration of 0.3 mM ¹⁵N-labeled tRNA^Lys3 was performed with 2D (¹H,¹⁵N)-TROSY experiments by adding increasing amount of unlabeled dsRBD up to 1 molar equivalent.

Optical rotations were measured on a JASCO P-1020 automatic digital polarimeter at room temperature. IR spectra were recorded on a Bruker Tensor 27 spectrometer using KBr pellets. UV spectra were recorded on a Shimadzu UV-2450 spectrophotometer (Shimadzu, Tokyo, Japan). High-resolution electrospray ionization mass spectrometry (HRESIMS) was obtained on an Agilent 6529B Q-TOF mass instrument using electrospray ionization. The 1D and 2D nuclear magnetic resonance (NMR) spectra were obtained on Bruker AVANCE III 500 MHz or Bruker AVIIIHD 600 MHz spectrometers in CDCl₃ with TMS as an internal standard. Analytical HPLC was conducted on an Agilent 1260 infinity system equipped with a DAD-UV detector. Preparative HPLC was carried out using a Shimadzu LC-6A system (Shimadzu, Tokyo, Japan) equipped with a Shim-pack RP-C₁₈ column (20 × 200 mm, i.d. 10 μm, Shimadzu, Tokyo, Japan) with a flow rate of 10.0 mL/min, detected by a binary channel UV detector. Silica gel (200–300 mesh, Qingdao Haiyang Chemical Co. Ltd., China), MCI (Mitsubishi, Japan), and RP-C₁₈ silica (40–63 μm, FuJi, Japan) were used for column chromatography.