Figure 5.
Figure 5 Structural features of the active site. a, The P3-L3
niche cradles the active site. The stereoview shows how the
phosphate ribose backbone crosses over from the P3-L3 stack to
P1.1 and back, passing through the unstacked nucleotide U23. The
ribose of G1 and the bases of the stacked nucleotides from J4/2
are shown. b, The P1.1 helix and the pedestal. c, A A-weighted
2|F[o]| - |F[c]| map44,45, with data from 20 to 2.3 Å, contoured
at 1 s.d., showing the nucleotides of J4/2 as seen from the
major groove of P1. d, The trefoil turn (orientated roughly as
in Fig. 3b) is the sharp twist in the RNA chain between G74 and
A77. This is stabilized by a complex network of interactions
between O2' groups and phosphate oxygens, a two-tiered ribose
zipper, and base-backbone hydrogen bonds. Figures 3, 4b, c and
5a, b, d were prepared with RIBBONS50.
The above figure is reprinted
by permission from Macmillan Publishers Ltd:
Nature
(1998,
395,
567-574)
copyright 1998.
A-weighted
2|F[o]| - |F[c]| map44,45, with data from 20 to 2.3 Å, contoured
at 1 s.d., showing the nucleotides of J4/2 as seen from the
major groove of P1. d, The trefoil turn (orientated roughly as
in Fig. 3b) is the sharp twist in the RNA chain between G74 and
A77. This is stabilized by a complex network of interactions
between O2' groups and phosphate oxygens, a two-tiered ribose
zipper, and base-backbone hydrogen bonds. Figures 3, 4b, c and
5a, b, d were prepared with RIBBONS50.