Table 1.

RNA atom pairs used to derive RNA-ion contacts

Ribose/phosphate backbone	Adenine side chain	Guanine side chain	Cytosine side chain	Uracil side chain
P, OP1	C2, N1	C2, N1	C2, N3	C2, N3
P, OP2	C2, N3	C2, N2	C2, O2	C2, O2
P, O5′	C4, N3	C2, N3	C4, N3	C4, N3
C1′ , O4′	C5, N7	C4, N3	C4, N4	C4, O4
C2′ , O2′	C6, N1	C5, N7
C3′ , O3′	C6, N6	C6, N1
C4′ , O4′	C8, N7	C6, O6
C5′ , O5′		C8, N7