17O chemical shift ranges (green, e) and MAS simulations (above) for various biologically relevant oxygen environments at (a) 11.7 T, (b) 16.4 T, (c) 21.1 T, and (d) 30.5 T (1.3 GHz 1H, in development at FBML-MIT100) using parameters for L-tyrosine • HCl for the carbonyl, carboxylic acid, and phenol oxygen environments81 and L-glycyl-glycine HCl monohydrate for the bound water environment (this work). (f) Green vertical lines are the isotropic 17O chemical shift determined within this study.