Table 7.

AARS groove recognition rules implied by the topmost four 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