. Author manuscript; available in PMC: 2014 Jul 6.

Published in final edited form as: J Am Chem Soc. 2011 Jan 5;133(5):1534–1544. doi: 10.1021/ja108943n

Table 1. ¹H, ¹³C, and ¹⁵N Isotropic Chemical Shifts (ppm) of Histidine in Different Protonation and Tautomeric States.

site		cationic	neutral τ tautomer	anionic τ tautomer	anionic π tautomer
¹³C	C′	173.2	175.6	183.4	183.2
	Cα	54.1	57.0	58.0	59.4
	Cβ	26.0	27.0	32.6	28.4
	Cγ	128.7	137.7	136.8	129.2
	Cε1	136.3	135.3	135.6	135.8
	Cδ2	119.4	113.6	113.0	125.4
¹⁵N	Nα	47.6	41.5	96.3	96.3
	Nδ1	190.0	249.4	252.7	171.8
	Nε2	176.3	171.1	167.3	248.2
¹H	H^N	8.6	9.0	7.4	6.2
	Hα	3.5	4.3	5.2	4.0
	Hβ	3.3	2.7	2.7	2.7
	Hδ1	16.8	NA	NA	12.7
	Hε2	12.6	13.7	12.2	NA
	Hδ2	8.0	4.9	5.3	6.4
	Hε1	9.3	6.1	5.6	7.2

Table 1. 1H, 13C, and 15N Isotropic Chemical Shifts (ppm) of Histidine in Different Protonation and Tautomeric States.