Syn and anti nucleosides: Difference between revisions
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== Purine Nucleosides == | == Purine Nucleosides == | ||
<applet load='Adenosine.pdb' size=' | <applet load='Adenosine.pdb' size='400' frame='true' align='right' scene ='Syn_and_anti_nucleosides/First_view/1'/> Observe that the adenine ring of adenosine is nearly perpendicular to the furanose ring (<scene name='Syn_and_anti_nucleosides/First_view/1'>Reset Initial scene</scene>) and that a <scene name='Syn_and_anti_nucleosides/Glycosidic_bond/1'>β glycosidic bond</scene> (colored green) connects adenine to ribofuranose. 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 the anti configuration is favored, 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 04:05, 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.
Purine NucleosidesPurine Nucleosides
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Observe that the adenine ring of adenosine is nearly perpendicular to the furanose ring () and that a (colored green) connects adenine to ribofuranose. Groups on the ribofuranose, such as the 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 shows the hinderance more realistically. and the , , same view but in . With purines the anti configuration is favored, 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 NucleosidesPyrimidine 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 NucleotidesExamples of Nucleotides
AMP ;
UMP ;
cAMP ;
Additional ResourcesAdditional Resources
For additional information, see: Nucleic Acids