Table 3.
Peptide sequences spanning residues K27–R40 from canonical H3, variant H3.3 and H3mm13 identified in mouse testis with various sets of PTMs. Detection of the diagnostic ions or neutral losses corresponding to KPTM was verified in the original MS/MS spectra using QualBrowser. The NCE was 27% in this analysis. CSprec designates the charge state of the precursor ion selected for fragmentation. Int (diag) is the intensity of the diagnostic ions for either N-terminal K27 or propionylated K36/K37; we set to 100 the one of higher intensity for comparing both. “%max int (diagKpro)” positions the diagnostic ion of Kpro as compared to the fragment of highest intensity in the MS/MS spectrum.
| Histone | Probable Identified Sequence | CSprec | Int (diagK27PTM) |
Int (diagKpro) |
Int (diagK27PTM)/Int (diagKpro) |
%Max Int (diagKpro) |
|---|---|---|---|---|---|---|
| Cano H3 | Kme1SAPATGGVKproKproPHR | 3 or 4 | 10.4 | 100 | 0.10 | 100 |
| Cano H3 | Kme3SAPATGGVKproKproPHR | 3 or 4 | N.A. (a) | 90 or 75 | ||
| H3.3 | Kme3SAPSTGGVKproKproPHR | 3 | N.A. (a) | 95 | ||
| Cano H3 | KacSAPATGGVKproKproPHR | 3 | 100 | 75 | 1.25 | 75 |
| H3.3 | KacSAPSTGGVKproKproPHR | 2 | 100 | 31 | 3.2 | 25 |
| H3mm13 | KacSVPSTGGVKproKproPHR | 3 | 3.1 | 100 | 0.03 | 97 |
| H3mm13 | KacSVPSTGGVKme2KproPHR | 4 | 95 | 100 | 0.95 | 10 |
| H3mm13 | KproSVPSTGGVKproKproPHR | 3 | N.A. | 100 | ||
| H3.3 | K(me1pro)SAPSTGGVKproKproPHR | 3 | 23 | 100 | 0.23 | 100 |
| H3.3 | K(me1pro)SAPSTGGVK(me1pro)KproPHR | 2 | 100 | 80 | 1.25 | 12 |
(a) Kme3 does not produce a diagnostic ion, yet we always verified the loss of trimethylamine (−59) from fragment b3, and possibly from b3-H2O, b2 or a2.