1 20 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 ACUUGGUUUA GGUAAUGAGU LOOP1 9 12 Crystallography ? ? Angstroms 1 A O3' 0.388 4.277 -8.803 2 C P -0.386 3.091 -8.033 O3' -3.398 4.158 -3.062 3 U P -4.685 3.621 -2.254 O3' -8.138 4.936 1.024 4 U P -9.126 3.683 1.235 O3' -13.549 2.342 -1.041 5 G P -13.538 0.878 -0.379 O3' -19.061 1.079 -1.395 6 G P -19.753 -0.197 -0.687 O3' -20.136 -4.916 -4.077 7 U P -19.261 -6.223 -3.734 O3' -18.793 -9.707 -7.917 8 U P -17.953 -11.075 -7.792 O3' -13.079 -12.447 -10.769 9 U P -12.331 -13.862 -10.967 O3' -9.235 -15.884 -6.585 10 A P -9.892 -16.815 -5.443 O3' -9.607 -13.592 -1.043 11 G P -9.961 -12.023 -1.054 O3' -6.038 -7.816 -1.567 12 G P -7.457 -7.055 -1.518 O3' -2.990 -6.602 -4.092 13 U P -1.450 -7.082 -4.075 O3' -2.713 -7.523 -9.766 14 A P -3.337 -7.320 -11.241 O3' -6.065 -7.380 -14.895 15 A P -5.681 -6.057 -15.736 O3' -9.567 -2.734 -16.979 16 U P -8.928 -1.297 -17.325 O3' -13.267 1.170 -16.693 17 G P -13.559 2.729 -16.976 O3' -17.178 6.025 -13.695 18 A P -16.846 7.553 -13.309 O3' -18.074 10.659 -9.462 19 G P -17.409 12.125 -9.554 O3' -13.464 14.668 -6.083 20 U P -12.264 15.742 -6.149 O3' -7.418 14.367 -2.474 12 syn 1 20 - - c 2 19 + + c 3 18 - - c 4 17 W W c 6 15 W W c 6 16 W W c 7 14 - - c 8 13 W W c 5 16 ! ! ! 3 12 ! ! ! 9 11 ! ! ! 1 20 8 SG1 9 12 1 8.267 0.000 2 8.267 61.135 3 8.267 122.270 4 8.267 183.404 5 8.267 244.539 6 8.267 305.674 7 8.267 366.809 8 8.267 427.943 9 0.000 497.575 10 46.569 550.000 11 116.690 550.000 12 163.258 497.575 13 154.991 427.943 14 154.991 366.809 15 154.991 305.674 16 154.991 244.539 17 154.991 183.404 18 154.991 122.270 19 154.991 61.135 20 154.991 0.000