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A-RNA tour

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Now change the display to make the show the <scene name='72/725869/Rna_space_filling_bbone/1'>sugar-phosphate backbone as pseudo-bonds</scene> connecting the phosphate atoms. Now the bases are easier to see. Notice how they are stacked upon each other but not perpendicular to the axis of the double helix. They are also displaced to the side of the axis. The result is a wide, short helix. Note also that the backbone forms a smooth, continuous curve.
Now change the display to make the show the <scene name='72/725869/Rna_space_filling_bbone/1'>sugar-phosphate backbone as pseudo-bonds</scene> connecting the phosphate atoms. Now the bases are easier to see. Notice how they are stacked upon each other but not perpendicular to the axis of the double helix. They are also displaced to the side of the axis. The result is a wide, short helix. Note also that the backbone forms a smooth, continuous curve.
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You can <scene name='72/725442/Zoom_pairs/1'>look at just four of the base pairs</scene>.You are looking into the major groove and the colors of the base pairs alternate. You can also <scene name='72/725442/Zoom_pairs_only/1'>looks at just the bases</scene>.
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You can <scene name='72/725869/Zoom_pairs/1'>look at just four of the base pairs.</scene>.You are looking into the major groove and the colors of the base pairs alternate. You can also <scene name='72/725869/Zoom_pairs_only/1'>look at just the bases</scene>.
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Each base pair stacks on the next similarly, as shown from <scene name='72/725442/Zoom_pairs_top/1'>this top view</scene>. This is the <scene name='72/725442/Zoom_pairs_only_top/1'>same top view of just the bases</scene>. A-form DNA also stacks in this way, but compare this with Z-DNA, which behaves much differently.
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Each base pair stacks on the next similarly, as shown from <scene name='72/725869/Zoom_pairs_top/1'>this top view</scene>. This is the <scene name='72/725869/Zoom_pairs_only_top/1'>same top view of just the bases</scene>.
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B-DNA stacks similarly, but compare this with Z-DNA, which behaves much differently. Essentially all helical RNA is in A form, but DNA can also be found in A form under certain conditions (particularly in RNA-DNA hybrids).
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The 2'-OH of ribose
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DNA is usually found in the B form under physiological conditions. The B-form conformation is stabilized by water molecules bound to the minor groove. You can see them as red dots <scene name='72/725442/Water_spine/1'>in this view</scene>. Sometimes kinks are found in the B helix at transcriptional control regions. These kinks can either be intrinsic to the DNA sequence or caused by transcription factor binding.
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You can compare it with the DNA forms by looking at this [http://proteopedia.org/wiki/images/d/d3/JnABZ3d.gif 3D red-blue stereo picture of A, B, and Z DNA]
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You can compare it with the DNA forms by looking at this [http://proteopedia.org/wiki/images/d/d3/JnABZ3d.gif 3D red-blue stern picture of A, B, and Z DNA]
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</StructureSection>
</StructureSection>
== References ==
== References ==

Revision as of 15:15, 21 February 2016

A-form RNA

A-RNA

Drag the structure with the mouse to rotate

References

R. E. Dickerson, H. R. Drew, B. N. Conner, R. M. Wing, A. V. Fratini & M. L. Kopka (1982) The anatomy of A-, B-, and Z-DNA. Science 216: 475-485 [1] JSmol in Proteopedia [2] or to the article describing Jmol [3] to the rescue.

Proteopedia Page Contributors and Editors (what is this?)

James Nolan, Michal Harel

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