Table 3.

Potential hydrogen bonds of 2′,5′-ADP with RNase A (present study), EDN (Leonidas et al. 2001a) and ECP (Mohan et al. 2002)

				Distance (Å)
2′,5′-ADP	RNase A	EDN	ECP	RNase A mol. I	RNase A mol. II	EDN	ECP
O1P	His119 Nδ1	His129 Nδ1	Lys38 Nζ	2.7	—	2.7	2.8
O2P	Lys41 Nå	Gln14 Nɛ2	Gln14 Nɛ2	2.9	—	3.3	3.0
O3P	His12 Nɛ2	His15 Nɛ2	His15 Nɛ2	2.6	—	2.6	3.0
O3P	Phe120 N	Leu130 N		2.9	—	2.8	—
O5P	His12 Nɛ2			—	2.9	—	—
O5P	Phe120 N			—	2.8	—	—
O6P	Gln11 Nɛ2		Arg34 Nη2	—	2.9	—	2.7
O3′		Leu130 O		—	—	2.6	—
O5′	His119 Nδ1			—	2.7	—	—
N3			His128 Nɛ2	—	—	—	3.3
N6	Asn71 Oδ1			—	3.1	—	—
N3	Water			2.9	3.2	2.9	—
N3	Water			—	2.8	—	—
N6	Water			3.2	—	—	—
N7	Water			—	3.1	—	—
O3′	Water			2.7	—	—	—
O3′	Water			3.2	—	—	—
O4′	Water			—	2.7	—	—
O5′	Water			—	2.2	—	—
O1P	Water			—	2.6	—	—
O2P	Water			2.8	3.0	—	3.1
O3P	Water			2.9	2.0	2.8	2.4
O4P	Water			2.5	2.5	2.9	2.7
O4P	Water			—	2.6	—	—
O5P	Water			2.6	2.8	—	—
O6P	Water			2.2	2.5	—	2.7
O6P	Water			—	3.0	—	—

Hydrogen bond interactions were calculated with the program HBPLUS (McDonald and Thornton 1994). Atom names are shown in Figure 1 ▶.