1 20 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 GGACUAGCGG AGGCUAGUCC LOOP1 9 12 Crystallography ? ? Angstroms 1 G O3' 4.450 -8.348 5.069 2 G P 3.911 -6.929 4.449 O3' 3.433 -6.315 -1.082 3 A P 3.158 -4.711 -1.120 O3' 0.835 -4.121 -6.382 4 C P -0.158 -2.913 -6.800 O3' -5.077 -2.695 -8.153 5 U P -5.143 -1.128 -8.558 O3' -10.095 1.306 -7.286 6 A P -10.295 2.887 -6.944 O3' -13.742 5.235 -3.699 7 G P -13.751 6.859 -3.615 O3' -14.031 9.941 0.917 8 C P -14.865 10.543 2.183 O3' -12.007 13.858 4.999 9 G P -13.401 14.532 4.508 O3' -11.064 19.638 2.502 10 G P -10.927 20.451 1.098 O3' -5.031 19.680 -1.119 11 A P -5.087 19.975 -2.702 O3' -1.632 16.336 -4.974 12 G P -0.126 16.901 -5.218 O3' 1.076 13.136 -2.627 13 G P 0.894 13.561 -1.104 O3' 2.562 8.817 2.234 14 C P 2.511 7.263 2.725 O3' 0.267 5.334 7.289 15 U P 0.176 3.725 7.528 O3' -4.824 2.273 10.371 16 A P -5.146 0.750 10.830 O3' -9.357 -2.085 9.010 17 G P -9.417 -3.719 8.962 O3' -11.980 -6.649 4.884 18 U P -11.468 -8.067 4.263 O3' -13.176 -10.036 -0.501 19 C P -13.004 -11.638 -0.482 O3' -9.782 -14.706 -2.916 20 C P -9.940 -16.048 -2.038 O3' -6.753 -19.682 -0.886 10 syn 11 syn 1 20 + + c 2 19 + + c 3 18 - - c 4 17 W W c 5 16 - - c 6 15 - - c 7 14 + + c 8 13 + + c 6 14 ! ! ! 8 9 ! ! ! 1 20 8 SG1 9 12 1 154.991 0.000 2 154.991 61.135 3 154.991 122.270 4 154.991 183.404 5 154.991 244.539 6 154.991 305.674 7 154.991 366.809 8 154.991 427.943 9 163.258 497.575 10 116.690 550.000 11 46.569 550.000 12 0.000 497.575 13 8.267 427.943 14 8.267 366.809 15 8.267 305.674 16 8.267 244.539 17 8.267 183.404 18 8.267 122.270 19 8.267 61.135 20 8.267 0.000