Table 2.

Hydrogen Bonds Involving PYR

donor	acceptor	distance (Å)
PYR 1P,a N6	D354β1 Oδ2	2.69
PYR 1P, N14	D240β1 Oδ2	3.08
Arg 211β1, NH1	PYR1P, N1	3.23
Arg 211β1, NH2	PYR1P, N1	2.99
PYR 1P, N13	E491β1, Oε2	2.65
PYR 2P,a N6	D354β2 Oδ2	2.64
PYR 2P, N14	D240β2 Oδ2	3.03
Arg 211β2, NH1	PYR2P, N1	2.95
Arg 211β2, NH2	PYR2P, N1	3.15
PYR 2P, N13	E491β2, Oε2	2.73
Wat 20 HOH	PYR 2P, Cl1	3.09

^aPYR 1P refers to pyrimethamine bound to monomer β1 of the asymmetric unit, and PYR 2P refers to pyrimethamine bound to monomer β2. PYR numbering can be found in Figure 1b and is the same as that used for PDB code 2BL9.¹⁴