Z-DNA model tour: Difference between revisions
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==Z-form DNA model== | ==Z-form DNA model== | ||
<StructureSection load='5zna' size='400' side='right' caption=' | Source <ref>PMID:7071593</ref> | ||
<StructureSection load='5zna' size='400' side='right' caption='Z-DNA [[5zna]]' scene='72/725870/Z-dna_overview/1'> | |||
== Structural highlights == | == Structural highlights == | ||
<UL> | <UL> | ||
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Now change the display to make it show the <scene name='72/725870/Space_filling_bbone/1'>sugar-phosphate backbone as pseudo-bonds</scene> connecting the phosphate atoms. Now the bases are easier to see. Now the bases are easier to see. Notice how they are stacked upon each other and are nearly perpendicular to the axis of the double helix. But notice that the base pairs do not stack upon each other equivalently. The backbone also is not a continuous curve, it "zig-zags" back and forth (hence "Z"-DNA). | Now change the display to make it show the <scene name='72/725870/Space_filling_bbone/1'>sugar-phosphate backbone as pseudo-bonds</scene> connecting the phosphate atoms. Now the bases are easier to see. Now the bases are easier to see. Notice how they are stacked upon each other and are nearly perpendicular to the axis of the double helix. But notice that the base pairs do not stack upon each other equivalently. The backbone also is not a continuous curve, it "zig-zags" back and forth (hence "Z"-DNA). | ||
<scene name='72/725870/Zoom_pair/ | <scene name='72/725870/Zoom_pair/2'>In this view</scene>, the molecule is shown in stick representation, with the backbone in yellow and sets of base pairs in red and blue. Notice how the blue bases stack well on the adjacent blue ones, but not on adjacent red ones, and vice versa. So it is the dinucleotide unit, rather than mononucleotide that is the repeating unit of the structure. This explains the need for alternating purines and pyrimidines to form Z-DNA. | ||
You can see <scene name='72/725870/Zoom_pairs_only/ | You can see <scene name='72/725870/Zoom_pairs_only/2'>the same view without the backbone</scene> here.Going 5' to 3', there is good stacking within the GpC dinucleotide, but not between them (CpG). | ||
A <scene name='72/725870/Zoom_pair_top/1'>top view</scene> also illustrates the stacking arrangement. You can also see this <scene name='72/725870/Zoom_pairs_only_top/1'>top view of just the bases.</scene>. Note the stacking of red base pairs on each other is much different than the stacking of red on blue. | |||
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] | You can compare it with the other 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] | ||
</StructureSection> | </StructureSection> | ||
==See Also== | |||
* [[Z-DNA]] | |||
* [[B-DNA tour]] | |||
* [[A-RNA tour]] | |||
* A more general overview will be found at [[DNA]]. | |||
* [[Forms of DNA]] shows a side-by-side comparison of A, B, and Z forms of DNA. | |||
* An interactive tutorial on [http://dna.molviz.org DNA Structure], ''disponible también en español'' and eight other languages. | |||
== References == | == References == | ||
JSmol in Proteopedia <ref>DOI 10.1002/ijch.201300024</ref> or to the article describing Jmol <ref>PMID:21638687</ref> to the rescue. | JSmol in Proteopedia <ref>DOI 10.1002/ijch.201300024</ref> or to the article describing Jmol <ref>PMID:21638687</ref> to the rescue. | ||
<references /> | |||