Syn and anti nucleosides
From Proteopedia
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== Purine Nucleosides == | == Purine Nucleosides == | ||
| - | <applet load='Adenosine.pdb' size='400' frame='true' align='right' scene ='Syn_and_anti_nucleosides/First_view/1'/> Adenosine (<scene name='Syn_and_anti_nucleosides/First_view/1'>Reset Initial scene</scene>) is composed of an adenine bonded to a furanose by a <scene name='Syn_and_anti_nucleosides/Glycosidic_bond/1'>β glycosidic bond</scene> (colored green). Observe that the adenine ring is nearly perpendicular to the furanose ring. Without hinderance from groups on either ring the adenine ring can rotate about the glycosidic bond, and | + | <applet load='Adenosine.pdb' size='400' frame='true' align='right' scene ='Syn_and_anti_nucleosides/First_view/1'/> Adenosine (<scene name='Syn_and_anti_nucleosides/First_view/1'>Reset Initial scene</scene>) is composed of an adenine bonded to a furanose by a <scene name='Syn_and_anti_nucleosides/Glycosidic_bond/1'>β glycosidic bond</scene> (colored green). Observe that the adenine ring is nearly perpendicular to the furanose ring, but projecting away from the furanose (anti-conformation). Without hinderance from groups on either ring the adenine ring can rotate about the glycosidic bond, and form the <scene name='Syn_and_anti_nucleosides/Syn-conformation/1'>syn-conformation</scene>. The two common purines, adenine and guanine, can rotate between the anti- and syn-conformations, but the anti-configuration is favored. Compare the contact present between the two rings in these two spacfilling representations, anti-conformation and syn-conformation. Groups on the ribofuranose, such as the <scene name='Syn_and_anti_nucleosides/2_hydrogen/1'>hydrogen</scene> on the 2' carbon, sterically hinder the rotation of the adenine about the glycosidic bond. This lack of ability to rotate results in two possible configurations. The anti configuration, which you are now viewing, but <scene name='Syn_and_anti_nucleosides/Anti_configuration/1'>spacefill</scene> shows the hinderance more realistically. and the <scene name='User:Karl_Oberholser/Sandbox_1/Syn_configuration/1'>syn configuration</scene>, <scene name='User:Karl_Oberholser/Sandbox_1/Syn_configuration2/1'>view of adenine ring on edge</scene>, same view but in <scene name='User:Karl_Oberholser/Sandbox_1/Syn_configuration3/1'>spacefill</scene>. With purines, but the syn configuration can be formed and actually has a role in the formation of the [[Z-DNA]], a conformation of DNA double helix. |
== Pyrimidine Nucleosides == | == Pyrimidine Nucleosides == | ||
Revision as of 20:54, 6 April 2011
The objective of this article is to highlight aspects of the 3D structure of nucleosides, but there are links to more general descriptions of nucleosides and nucleotides available in the External Links section.
Contents |
Purine Nucleosides
|
Pyrimidine Nucleosides
of uridine in the anti conformation. of cytidine in the syn conformation. oxygen at the C-2 position of cytidine invading the space of both hydrogen at C-2' and the oxygen of the furanose ring. Since both pyrimidines found in DNA have an oxygen at the C-2 position, nucleosides and nucleotides of these pyrimidines only adopt the anti conformation and therefore can not be part of Z-DNA.
Examples of Nucleotides
AMP ;
UMP ;
cAMP ;
Additional Resources
For additional information, see: Nucleic Acids
External Links
Proteopedia Page Contributors and Editors (what is this?)
Karl Oberholser, Angel Herraez, David Canner, Alexander Berchansky, Norbert Sträter
