Extended Data Fig. 7: NMR and UV analyses of chemically synthesized ava2C.
From: A tRNA modification with aminovaleramide facilitates AUA decoding in protein synthesis
a, Purification of the chemically synthesized ava2C nucleoside by reverse-phase HPLC. The peak indicated by the arrow was collected. b, Chemical structure of ava2C. The atom names correspond to those on the NMR charts (c–e). c,d, 1H NMR spectra of the chemically synthesized ava2C nucleoside in DMSO-d6 (c) and DMSO-d6 + D2O (d). The chemical shifts are shown in ppm using tetramethylsilane (TMS) or solvent (DMSO-d6) as an internal standard. Signals for protons x, y and z in DMSO-d6 disappeared in DMSO-d6 + D2O, indicating that protons x, y and z are solvent-exchangeable. e, 1H-1H COSY spectrum of chemically synthesized ava2C in DMSO-d6 + D2O. Cross-peaks between the assigned protons are indicated by dashed lines. f, Comparison of UV spectra of ava2C and L. The spectra were normalized at the maximum absorption wavelength. The two nucleosides showed almost identical spectra. g, UV spectra of synthetic ava2C in different pH solutions. Specifically, 50 mM sodium phosphate buffer (pH 2, 3 and 6–9), sodium acetate buffer (pH 4 and 5) and sodium borate buffer (pH 10) were used.
