Table 2.

Intermolecular contacts

Mutation	Nucleotide	Atom	Amino acid	Atom	Distance, Å
Yes	G5	O3′	Lys-317	NZ	3.72
	U6	O2P	Lys-317	CD	3.09
	U8	O1P	Gln-318	OE1	2.80
Yes	C11	O2′	Thr-321	O	2.86
	C12	O2P	Thr-321	N	2.89
Yes	A13	O1P	Gln-318	NE2	3.29
	A14	O1P	Thr-316	CG2	3.41*
	C25	O2′	Ser-326	N	3.60
	U35	O4	Arg-341	NH2	2.72
Yes	Ψ38	O2′	Asn-336	ND2	3.32
Yes	C69	O2′	Asp-319	OD1	3.63

Direct contacts between the backbone of tRNA^Gln and GlnRS observed at 2.5 Å resolution are listed (6). Other interactions are: U6 C4′, Lys-317 O, 3.43 Å; G10 N2, Glu-323 CD, 3.53 Å; G10 N2, Glu-323 OE1, 2.76 Å; C11 O2′, Ile-322 CA, 3.66 Å; C11 O3′, Thr-321 O, 3.09 Å; C11 O4′, Glu323 CD, 3.42 Å; C11 O4′, Glu323 OE2, 3.37Å; C12 O2P, Asn-320 CA, 3.35 Å; C25 O2′, Ala-325 C, 3.63 Å, U38 C4′, Asn-336 OD1, 3.53 Å; U38 O3′, Asn-336 ND2, 3.53 Å. Also, G15 interacts with Gln13 on the N-terminal helix (O1P-NE2, 3.83 Å) and Gln-13 interacts with Phe-10 on the same face of the helix (four distances, 3.30–3.88 Å). Phe-10 packs against the side chains of Val-315 and Thr-316 (six distances, 3.67–3.90 Å). 

^*Assumes a possible rotation of the side chain of Thr-316. The nonrotated distance is 3.84 Å.