Table 2.

AARS groove recognition rules implied by the four topmost acceptor-stem bases.

Term	Estimate	Implications
Intercept	−0.5
β-branched	−2.5	Coeff > 0;	β-branched=> minor groove
			Unbranched=> major groove
−1,Y/R	2	Coeff >0;	Base −1 purine => major groove
			Base −1 pyrimidine => minor groove
1,Y/R	0.5	Coeff > 0;	Base 1 pyrimidine => minor groove
			Base 1 purine => major groove
2,Y/R	1	Coeff > 0;	Base 2 pyrimidine => minor groove
			Base 2 purine => major groove
2,≡/=	1	Coeff > 0;	Base 2 G,C => minor groove
			Base 2 A U => major groove
72,≡/=	−0.5	Coeff < 0;	Base 72 G/C => major groove
			Base 72 A/U => minor groove
β-branched*2,Y/R	−4	Coeff < 0;	Branched sc with Base 2 = C,U => major groove
			Branched sc with Base 2 = G,A => minor groove
1,Y/R*72,≡/=	−0.5	Coeff < 0;	C=G => major groove;
			G=C => minor groove
			A=U => major groove
			U=A => minor groove
2,Y/R*73,Y/R	−1	Coeff < 0;	Base 2 = C,U and Base 73=C,U => major groove
			Base 2 = C,U Base 73 = G,A => minor groove
			Base 2 = G,A Base 73 =C,U => minor groove
			Base 2 = G,A Base 73 =G,A => major groove
2,Y/R*2,≡/=	−1	Coeff < 0;	C => major groove
			U => minor groove
			G => minor groove
			A => major groove
β-branched*72,≡/=	4.5	Coeff > 0;	Branched sc with Base 72 G, C => minor Groove
			Branched sc with Base 72 A, U => major Groove