1 21 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 GCGUCACACC GGUGAAGUCG C Crystallography ? ? Angstroms 1 G P -9.530 29.895 7.902 O3' -10.573 25.213 9.529 2 C P -9.467 24.165 9.001 O3' -9.975 19.353 7.659 3 G P -8.557 18.958 7.030 O3' -8.300 15.430 3.668 4 U P -6.907 15.118 2.952 O3' -5.330 13.300 -2.020 5 C P -3.784 13.181 -1.642 O3' -0.811 14.289 -5.609 6 A P 0.745 14.195 -5.194 O3' 4.196 16.766 -7.920 7 C P 5.572 16.083 -7.417 O3' 9.835 18.411 -6.300 8 A P 10.737 17.194 -5.748 O3' 14.227 17.771 -2.133 9 C P 14.706 16.257 -1.877 O3' 15.414 14.720 3.313 10 C P 15.673 13.188 3.787 O3' 15.273 11.269 8.400 11 G P 15.566 9.696 8.275 O3' 13.487 6.154 11.166 12 G P 14.026 4.788 10.516 O3' 11.042 0.561 10.447 13 U P 11.622 -0.696 9.632 O3' 8.828 -4.216 7.481 14 G P 9.761 -5.201 6.616 O3' 8.839 -7.577 2.589 15 A P 10.065 -8.378 1.929 O3' 12.714 -8.906 -2.834 16 A P 13.316 -7.909 -3.944 O3' 17.866 -9.615 -6.324 17 G P 18.530 -9.053 -7.672 O3' 19.992 -5.463 -9.935 18 U P 21.535 -5.425 -9.469 O3' 24.469 -1.400 -9.640 19 C P 25.890 -2.090 -9.353 O3' 29.543 1.075 -7.423 20 G P 30.889 0.356 -6.904 O3' 33.555 1.923 -2.839 21 C P 34.733 0.846 -2.625 O3' 36.381 -0.427 1.884 16 17 ! ! ! SG1 6 6 SG2 15 16 1 0.000 0.000 2 0.000 23.913 3 0.000 47.826 4 0.000 71.739 5 0.000 95.652 6 0.000 119.565 7 0.000 191.304 8 0.000 215.217 9 0.000 239.130 10 0.000 263.043 11 0.000 286.957 12 0.000 310.870 13 0.000 334.783 14 0.000 358.696 15 0.000 382.609 16 0.000 430.435 17 0.000 454.348 18 0.000 478.261 19 0.000 502.174 20 0.000 526.087 21 0.000 550.000 1 21 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 GCGUCACAC CGGUGAAGUC GC Crystallography ? ? Angstroms 1 G P 23.984 -11.624 5.506 O3' 24.596 -7.881 8.869 2 C P 23.502 -6.865 8.282 O3' 24.401 -1.863 8.981 3 G P 23.130 -1.081 8.374 O3' 23.289 3.672 6.375 4 U P 21.807 3.899 5.777 O3' 21.752 6.830 2.005 5 C P 20.284 7.219 1.482 O3' 18.217 7.574 -3.861 6 A P 16.622 7.735 -3.822 O3' 13.769 6.286 -7.666 7 C P 12.402 6.754 -6.957 O3' 8.207 4.469 -7.896 8 A P 7.133 5.271 -7.016 O3' 3.069 3.266 -4.980 9 C P 2.380 4.450 -4.121 O3' -0.120 3.189 0.245 10 C P -0.637 4.534 0.957 O3' -1.179 5.188 6.037 11 G P -1.561 6.746 6.188 O3' -0.026 9.734 9.929 12 G P -0.314 11.249 9.485 O3' 3.002 15.129 11.298 13 U P 2.766 16.642 10.810 O3' 6.121 20.363 10.646 14 G P 5.283 21.623 10.110 O3' 7.336 25.356 7.251 15 A P 6.041 26.222 7.588 O3' 4.120 28.985 3.590 16 A P 3.581 28.045 2.397 O3' 0.823 31.010 -1.098 17 G P -0.088 29.709 -1.440 O3' -0.891 28.786 -6.479 18 U P -2.467 28.516 -6.669 O3' -4.991 25.339 -9.325 19 C P -6.423 26.069 -9.265 O3' -10.571 22.893 -9.508 20 G P -11.939 23.646 -9.144 O3' -15.974 21.576 -6.771 21 C P -17.110 22.652 -6.347 O3' -20.128 21.411 -2.202 SG1 6 6 SG2 15 16 1 57.391 550.000 2 57.391 526.087 3 57.391 502.174 4 57.391 478.261 5 57.391 454.348 6 57.391 406.522 7 57.391 358.696 8 57.391 334.783 9 57.391 310.870 10 57.391 286.957 11 57.391 263.043 12 57.391 239.130 13 57.391 215.217 14 57.391 191.304 15 57.391 167.391 16 57.391 143.478 17 57.391 95.652 18 57.391 71.739 19 57.391 47.826 20 57.391 23.913 21 57.391 0.000 1 21 + + c 2 20 + + c 3 19 + + c 5 17 + + c 7 14 + + c 8 13 - - c 9 12 + + c 10 11 + + c 11 10 + + c 12 9 + + c 13 8 - - c 14 7 + + c 17 5 + + c 18 4 W W c 19 3 + + c 20 2 + + c 21 1 + + c 4 18 ! ! ! 1 21 5 7 14 8 17 5 5