1H–15N HSQC spectra
of (a) tau174–183, (b) tau211–219, (c) tau229–238, and (d) Ac-KTPP-NH2 peptides. Green,
peptides with unmodified Ser/Thr; blue, peptides with Thr(OGlcNAc);
magenta, peptides with Ser/Thr(OPO3H–) (pH 4); red, peptides with Ser/Thr(OPO32–) (pH 8).