TABLE 1.
Summary of Acr-modified peptides identified in recombinant H2A and H4 by LC-MS/MSa
| Peptide source and no. | Sequence | ΔMb (Da) |
|---|---|---|
| H2A | ||
| 1 | 89NDEELNK(FDP)LLGR99 | +94 |
| 2 | 89NDEELNK(MP)LLGR99 | +76 |
| 3 | 36K(MP)GNYAER42 | +76 |
| H4 | ||
| 1 | 4GK(MP)GGKGLGK12 | +76 |
| 2 | 4GKGGK(MP)GLGK12 | +76 |
| 3 | 9GLGK(MP)GGAK16 | +76 |
| 4 | 21VLRDNIQGITK(MP)PAIR35 | +76 |
| 5 | 24DNIQGITK(FDP)PAIR35 | +94 |
| 6 | 56GVLK(MP)VFLENVIR77 | +76 |
| 7 | 56GVLK(FDP)VFLENVIR77 | +94 |
| 8 | 68DAVTYTEHAK(MP)R78 | +76 |
| 9 | 68DAVTYTEHAK(A)R(A)78 | +38, +38 |
| 10 | 79K(MP)TVTAMDVVYALK91 | +76 |
| 11 | 78RK(FDP)TVTAM(oxidation)DVVYALK91 | +94 |
| 12 | 80TVTAMDVVYALK(MP)R92 | +76 |
| 13 | 80TVTAMDVVYALK(FDP)R92 | +94 |
a
H2A and H4 treated with 50 μM Acr were separated by PAGE, the corresponding gel bands were excised and digested with trypsin, and the resultant peptides were extracted and subjected to LC-MS/MS analysis. The MP- and FDP-modified peptides were identified in both H2A and H4 samples, and an aldimine (A)-modified peptide was also identified in H4 samples. Peptides 1 and 3 show the identification of H4K5MP and K12MP, respectively, demonstrating that both H4K5 and H4K12, two lysine residues critical for histone nuclear import, could be modified by Acr.
b
ΔM, mass difference.