Table 3.

Contacts, putative hydrogen bonds and one covalent bond, observed in the active site of H. pylori AdSS between the enzyme and three ligands present, PLP, IMP and sulphate ion.

PLP		IMP		SO4
Hydrogen bond	Length [Å]	Hydrogen bond	Length [Å]	Hydrogen bond	Length [Å]
O3 ··· Nζ Lys322	2.41	O3P ··· NH1 Arg135*	2.80	O1 ··· NH1 Arg296	3.08
O3 ··· O H2O634	2.60	O3P ··· O H2O657	2.65	O2 ··· O H2O722	2.78
C4A ― Nζ Lys322	1.26	O3P ··· O H2O6761	2.69	O2 ··· O H2O777	3.18
O4P ··· N Gly14	3.39	O2P ··· Oγ1 Thr230	2.61	O3 ··· NH2 Arg294	3.10
O1P ··· N Gly16	2.95	O2P ··· Nδ2 Asn37	2.79	O3 ··· O H2O723	2.78
O1P ··· N Lys15	3.30	O1P ··· Oγ1 Thr121	2.56	O4 ··· Nζ Arg294	2.69
O1P ··· O H2O653	2.64	O1P ··· N Thr121	2.83	O4 ··· Nε Arg294	3.34
O2P ··· Nζ Lys15	2.61	O1P ··· O H2O683	2.77
O2P ··· N Lys15	2.86	O3’ ··· O Val264	2.99
O2P ··· N Gly14	2.97	O3’ ··· O H2O631	2.59
O3P ··· O H2O692	2.72	O3’ ··· O H2O713	3.10
O3P ··· O H2O729	2.86	O2’ ··· O Val264	2.73
		O2’ ··· NH2 Arg294	2.79
		O2’ ··· O Gly119	3.21
		N3 ··· O H2O662	2.96
		N1 ··· Oδ1 Asp12	3.06
		N1 ··· O H2O723	3.30
		O6 ··· O H2O692	3.01
		O6 ··· O Asn37	3.37

··· - hydrogen bond, ― - covalent bond, * - amino acid from the neighbouring subunit. Water molecules are numbered according to the PDB file 8QWA, in which the structure is deposited.