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Histidine structure and chemistry lie at the heart of many enzyme active sites, ion channels, and metalloproteins. While solid-state NMR spectroscopy has been used to study histidine chemical shifts, the full pH dependence of the complete panel of ¹⁵N, ¹³C, and ¹H chemical shifts and the sensitivity of these chemical shifts to tautomeric structure have not been reported. Here we use magic-angle-spinning solid-state NMR spectroscopy to determine the ¹⁵N, ¹³C, and ¹H chemical shifts of histidine from pH 4.5 to 11. Two-dimensional homonuclear and heteronuclear correlation spectra indicate that these chemical shifts depend sensitively on the protonation state and tautomeric structure. The chemical shifts of the rare π tautomer were observed for the first time, at the most basic pH used. Intra- and intermolecular hydrogen bonding between the imidazole nitrogens and the histidine backbone or water was detected …