Table I. PBL13 phosphopeptides identified by LC-MS/MS analysis.
Recombinant His6-PBL13 and His6-PBL13K111A were subjected to in vitro kinase assays followed by trypsin digestion and TiO2 phosphopeptide enrichment before LC-MS/MS analyses. Phosphopeptide spectra were analyzed using the LuciPHOr algorithm for perform phosphosite localization. Reported phosphopeptides required a LuciPHOr global false localization rate score of less than 0.05 and were manually validated. No phosphorylated peptides were identified from His6-PBL13K111A samples; s, t, and y denote phosphorylated Ser, Thr, and Tyr, respectively, whereas m and e denote oxidized Met and dehydrated Glu, respectively.
| Residue | Peptide Sequence |
|---|---|
| S240 | (K)DGPQGDDTHVsTR(V) |
| S321 | (R)LEDQYsEtGAR(K) |
| T323 | (R)LEDQYSEtGARK(A) |
| T383 and S384 or T443 and S444 | (R)REVKEtsLQNFDKPR(R/N) |
| T383 or 428 or T443 | (R)REVKEtSLQNFDK(P/T) |
| T383 or T443 | (R)EVKEtSLQNFDKPR(R/N) |
| S384 or S429 or S444 | (R)EVKETsLQNFDK(P/T) |
| S384 or S444 | (R)eVKETsLQNFDKPR(R/N) |
| T395, T398 | (R)REtKVtSLQNFDK(T) |
| T395 | (R)REtKVTSLQNFDK(T) |
| T398 | (R)RETKVtSLQNFDKTR(R) |
| T406 | (K)VTSLQNFDKtRR(E) |
| T413 | (R)EVKDtSLQNFDK(T) |
| T421 | (R)EVKDTSLQNFDKtRR(E) |
| S455 AND T456 | (R)NVstTDNHQKFR(S) |
| S455 | (R)NVsTTDNHQK(F) |
| Y481 | (R)NGyNSPmRNEAGGERY- |