Table 2.

Relative differences in the A−1:G+1 linkage due to active site modifications

2'-group at A−1	G8 Base	τ (°)	2'-O-to-P (Å)a	rmsd vanadate (Å)b	Position 8 contacts to the scissile bond (Å)c
2'-OMe	G	158	2.9	1.5 (−)	N1/2'-O (2.7); N2/pro-R (2.8)
2'-O-vanadate	G	144	2.0	− (1.5)	N1/2'-O (3.1); N2/pro-S (3.5); N2/2'-O (3.1)
2'-OMe	I	118	3.3	2.3 (1.0)	N1/2'-O (2.8)
2'-deoxy	I	-	-	2.6 (1.3)	none
2'-OH	DAP	98	3.1	2.9 (1.9)	N2/2'-O (3.3)
2'-OH	AP	112	3.2	3.0 (2.0)	N2/2'-O (3.4)
2'-OH	A	112	3.9	3.3 (2.3)	none
2'-OH	U	93	3.8	3.1 (2.1)	none

^aThis value represents the distance between the 2'-O-nucleophile and the phosphorus of G+1.

^bThis value indicates the deviation of the G+1 phosphorus of a given structure from the position of vanadium in the 4WJ-U1A-vanadate complex based on minimization of all core atoms. The value in parentheses is the rmsd relative to the G+1 phosphorus of the native G8 structure of this study.

^cEntries indicate position 8 functional group contacts to atoms of the phosphodiester bond between A−1 and G+1. Parenthetical values after each group of atoms indicate a distance as described in Figures 4A, 5 and 6B.