Table 1.

³¹P NMR titration pK_a derived for the 6 peptides based on the N-terminal sequence of histone H3 amino acid residues 3–16.

#	Peptide Sequence	Net charge (pH 7)	Modification	pKa Values	Mean pKa	Std. Dev.	Delta pKa (AASp)
1	TKQTARKSpTGGKAP	+2	None	5.55 5.60 5.51	5.55	0.05	0.37
2	TKQTARASpTGGKAP	+1	K9 to A	5.78 5.69 5.68	5.72	0.06	0.20
3	TKQTAAKSpTGGKAP	+1	R8 to A	5.68 5.90 5.91	5.83	0.13	0.09
4	TKQTAAASpTGGKAP	0	R8 to A and K9 to A	6.04 5.84 5.87	5.92	0.17	-
5	TKQTARSDMAKSpTGGKAP	+2	R8 SDMA	5.70 5.77	5.74	0.05	0.18
6	TKQTARSDMAASpTGGKAP	+1	K9 to A R8 SDMA	6.37 5.76	6.07	0.43	−0.15