Table 1.

Thermodynamic Parameters Obtained for ITC Titration and Screening Data Obtained from Fingerprint‐NMR Experiments for HisJ and Various Ligands at pH 7.0

Ligand	K d	N	ΔH (Kcal mol−1)	TΔS (Kcal mol−1)	NMR
l‐histidine	64 ± 10 nM	0.9 ± 0.5	−11.9 ± 0.6	−0.006	Slow
N‐acetyl l‐histidine	27 ± 9 μM	0.9 ± 0.0	−1.5 ± 0.3	0.015	+
l‐histidine amide	No bindinga	–	–	–	+
1‐methyl‐l‐histidine	18 ± 1 μM	1.6 ± 0.2	−0.7 ± 0.04	0.019	+
3‐methyl‐l‐histidine	3 ± 0.7 μM	0.5 ± 0.07	−7.21 ± 0.06	0.001	+
d‐histidine	No binding	–	–	–	–
β‐(1, 2, 4‐triazol‐3‐yl) dl‐alanine	No binding	–	–	–	+
Carnosine	No binding	–	–	–	+
Histamine	No binding	–	–	–	–
Cis‐Urocanic acid	No binding	–	–	–	–
Trans‐Urocanic acid	No binding	–	–	–	–
Imidazole	No binding	–	–	–	–
1,2,4‐triazole	No binding	–	–	–	–
l‐glycine	No binding	–	–	–	–
l‐arginine	3 ± 1 μM	1 ± 0.04	0.53 ± 0.02	0.027	Slow
Homo‐l‐arginine	2 ± 0 μM	1 ± 0	2.52 ± 0.01	0.034	+
Nα‐acetyl‐l‐arginine	No binding	–	–	–	+
l‐arginine amide	No binding	–	–	–	+
N G‐methyl‐l‐arginine	1.3 ± 0.8 μM	0.9 ± 0.2	−3.2 ± 0.8	0.016	+
N G, N G‐ dimethyl‐l‐arginine	No‐binding	–	−	−	+
N G, N G′‐ dimethyl‐l‐arginine (asymmetric)	6 ± 1 μM	0.3 ± 0.05	6.54 ± 1	0.045	+
l‐lysine	19.5 ± 6 μM	1 ± 0	2.3 ± 0.06	0.029	Fast
Nα‐acetyl l‐lysine	No binding	–	–	–	+
Nɛ‐acetyl‐l‐lysine	No binding	–	–	–	+
l‐lysine amide	No binding	–	–	–	+
Nɛ, Nɛ‐dimethyl‐l‐lysine	No binding	–	–	–	+
Nɛ, Nɛ, Nɛ‐trimethyllysine	No binding	–	–	–	+
l‐ornithine	72 ± 4 μM	1.3 ± 0.4	1.7 ± 0.1	0.020	Fast
l‐2, 4‐diaminobutyric acid	No binding	–	–	–	+
2,6‐diaminopimelic acid	No binding	–	–	–	–

The ITC data are the average of at least three experiments with standard deviation. For the NMR data “+” means changes were observed in the HSQC spectra implying ligand binding, while “−” means no changes could be detected and the ligand did not bind.

^aNo binding means that binding was tested but was too weak to be observed by ITC.