Long-distance combinatorial linkage between methylation and acetylation on histone H3 N termini -- Taverna et al. 104 (7): 2086 Data Supplement - HTML Page - index.htslp -- Proceedings of the National Academy of Sciences

Taverna et al. 10.1073/pnas.0610993104.

Supporting Information

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SI Figure 4
SI Table 1
SI Table 2
SI Text

SI Figure 4

Fig. 4. T. thermophila histone H3 (gi 59799577).

Table 1. Peptides from the H3 Glu-C digest as detected by FTMS

Mass measured	Mass calculated	Error, ppm	Residue
5,337.0849	5,337.0955	1.99	1-50
3,336.933	3,336.9378	1.4	51-77
3,812.1804	3,812.1809	0.13	51-81
1,461.8075	1,461.806	0.9	82-94
911.489	911.4873	1.9	98-105
3,571.902	3,571.8995	0.7	106-135
1,532.8564	1,532.859	1.7	124-135

These data were obtained by manual interpretation only and the focus was placed on dominant masses. Please see SI Table 2 for observed masses of residue 1-50.

SI Text

Self-Packed HPLC Columns for Analysis with Mass Spectrometry

Peptide mixtures were pressure-loaded onto self-packed C18 capillary precolumns [360 mm o.d, 75 mm i.d. fused silica capillary with polyamide coating (Polymicro Technologies, Phoenix, AZ] packed with 5 cm of irregular (5-20 mm) C18 silica beads (YMC ODS-AQ, Waters, Milford, MA) and equipped with a LiChrosorb Si 60 frit (EMD Chemicals Inc., Gibbstown, NJ). The column was washed for 5-10 min with 0.1% acetic acid at a pressure of ~ 500 psi and then connected with Teflon tubing to a self-packed capillary analytical column (360 mm o.d., 50 mm i.d. fused silica capillaries with polyamide coating) packed with 7 cm of regular (5 mm) C18 silica beads with integrated emitter tip (~ 3 mm).

Precursor Isolation

To exclude the possibility of mixed spectra originating from different precursor masses, the isolation window was set to ± 0.5 Da. Recall that the charge states chosen for dissociation are typically +10 and few are +9. The difference of one methyl group at the +10 charge state is only 1.4 Da. To unambiguously show that the isolated mass is not a composite of two masses differing by 14 Da the isolated precursor was first charged reduced to the +3 and +4 charge state using exclusively the PTR reaction. In the +3 and +4 charge state the difference of 14 Da is 4.7 and 3.5 Da, respectively, and readily observable if present. In no instance were two different species obtained in the charge-reduced spectra, and we concluded that only the mass of interest was isolated.