Table 2. Summary of Key Ser/Thr NMR Data for All Peptidesa.
| peptide | δ (HN) | 3JαN | δ (Hα) | δ (H-acetyl) |
|---|---|---|---|---|
| Ac-SerKAAAAKAAAAKAAGY-NH2 | 8.58 | 5.1 | 4.34 | 2.10 |
| Ac-Ser(OGlcNAc)KAAAAKAAAAKAAGY-NH2 | 8.62 | 3.3 | 4.33 | 2.13, 2.07 |
| Ac-Ser(OPO3H–)KAAAAKAAAAKAAGY-NH2 | 8.91 | 4.4 | 4.40 | 2.13 |
| Ac-Ser(OPO32–)KAAAAKAAAAKAAGY-NH2 | 9.41 | 3.6 | 4.29 | 2.15 |
| Ac-ThrKAAAAKAAAAKAAGY-NH2 | 8.40 | 6.2 | 4.25 | 2.12 |
| Ac-Thr(OGlcNAc)KAAAAKAAAAKAAGY-NH2 | 8.34 | 5.1 | 4.18 | 2.15, 2.08 |
| Ac-Thr(OPO3H–)KAAAAKAAAAKAAGY-NH2 | 8.80 | 4.8 | 4.23 | 2.16 |
| Ac-Thr(OPO32–)KAAAAKAAAAKAAGY-NH2 | 9.57 | 3.5 | 4.04 | 2.16 |
| Ac-ASerAAAAKAAAAKAAGY-NH2 | 8.62 | 5.7 | 4.41 | 2.07 |
| Ac-ASer(OPO3H–)AAAAKAAAAKAAGY-NH2 | 8.97 | 5.1 | 4.51 | 2.09 |
| Ac-ASer(OPO32–)AAAAKAAAAKAAGY-NH2 | 9.57 | 4.3 | 4.41 | 2.13 |
| Ac-AThrAAAAKAAAAKAAGY-NH2 | 8.63 | 4.7 | 4.26 | 2.06 |
| Ac-AThr(OPO3H–)AAAAKAAAAKAAGY-NH2 | 9.08 | ndb | 4.16 | 2.11 |
| Ac-AThr(OPO32–)AAAAKAAAAKAAGY-NH2 | ||||
| 278 K | 10.24 | 3.7 | 4.02 | 2.15 |
| 285 K | 10.15 | 4.0 | 4.02 | 2.14 |
| 298 K | 9.94 | 4.0 | 4.04 | 2.13 |
| 305 K | 9.81 | 4.9 | 4.05 | 2.12 |
| Ac-AKAASerAKAAAAKAAGY-NH2 | 8.44 | ndc | 4.37 | 2.05 |
| Ac-AKAASer(OGlcNAc)AKAAAAKAAGY-NH2 | 8.45 | ndc | 4.46 | 2.04, 2.02 |
| Ac-AKAASer(OPO3H–)AKAAAAKAAGY-NH2 | 8.71 | 5.7 | 4.51 | 2.03 |
| Ac-AKAASer(OPO32–)AKAAAAKAAGY-NH2 | 9.06 | 4.5 | 4.44 | 2.03 |
| Ac-AKAAThrAKAAAAKAAGY-NH2 | 8.29 | ndc | 4.23 | 2.04 |
| Ac-AKAAThr(OGlcNAc)AKAAAAKAAGY-NH2 | 8.16 | ndc | 4.34 | 2.06, 2.01 |
| Ac-AKAAThr(OPO3H–)AKAAAAKAAGY-NH2 | 8.57 | ndc | 4.36 | 2.02 |
| Ac-AKAAThr(OPO32–)AKAAAAKAAGY-NH2 | 9.50 | 4.1 | 4.11 | 2.01 |
| Ac-AKAAAAKAASerAKAAGY-NH2 | 8.30 | ndc | 4.37 | 2.06 |
| Ac-AKAAAAKAASer(OPO3H–)AKAAGY-NH2 | 8.54 | ndc | 4.50 | 2.03 |
| Ac-AKAAAAKAASer(OPO32–)AKAAGY-NH2 | 9.01 | 3.3 | 4.42 | 2.03 |
| Ac-AKAAAAKAAThrAKAAGY-NH2 | 8.19 | 6.8 | 4.25 | 2.06 |
| Ac-AKAAAAKAAThr(OPO3H–)AKAAGY-NH2 | 8.44 | ndc | 4.40 | 2.02 |
| Ac-AKAAAAKAAThr(OPO32–)AKAAGY-NH2 | 9.41 | 4.5 | 4.09 | 2.03 |
| Ac-YGAKAAAAKAAAAKASer-NH2 | 8.22 | ndc | 4.37 | 1.99 |
| Ac-YGAKAAAAKAAAAKASer(OGlcNAc)-NH2 | 8.30 | ndc | 4.48 | 2.03, 1.98 |
| Ac-YGAKAAAAKAAAAKASer(OPO3H–)-NH2 | 8.57 | 6.8 | 4.50 | 1.97 |
| Ac-YGAKAAAAKAAAAKASer(OPO32–)-NH2 | 9.02 | 6.3 | 4.42 | 1.98 |
| Ac-YGAKAAAAKAAAAKAThr-NH2 | 8.18 | 7.9 | 4.29 | 1.98 |
| Ac-YGAKAAAAKAAAAKAThr(OGlcNAc)-NH2 | 8.18 | 8.0 | 4.42 | 2.05, 1.98 |
| Ac-YGAKAAAAKAAAAKAThr(OPO3H–)-NH2 | 8.42 | 7.9 | 4.39 | 1.98 |
| Ac-YGAKAAAAKAAAAKAThr(OPO32–)-NH2 | 8.93 | 6.2 | 4.26 | 1.99 |
a
Chemical shifts (δ) [amide (HN) and Hα] and backbone coupling constants (3JαN, which corresponds to the ϕ torsion angle) of serine or threonine resonances and acetyl (N-terminal and OGlcNAc) resonances for all Ser- and Thr-containing peptides. Experiments were conducted at 278 K (unless otherwise indicated) in 5 mM phosphate buffer with 25 mM NaCl at pH 7.2 (dianionic phosphorylated peptides) or pH 4 (other peptides). Complete NMR data are given in the Supporting Information.
b
Not determined due to broadening.
c
Not determined due to spectral overlap.