2axb
From Proteopedia
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[[Image:2axb.gif|left|200px]] | [[Image:2axb.gif|left|200px]] | ||
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| - | + | {{STRUCTURE_2axb| PDB=2axb | SCENE= }} | |
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'''Crystal Structure Analysis Of A 2-O-[2-(methoxy)ethyl]-2-thiothymidine Modified Oligodeoxynucleotide Duplex''' | '''Crystal Structure Analysis Of A 2-O-[2-(methoxy)ethyl]-2-thiothymidine Modified Oligodeoxynucleotide Duplex''' | ||
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==About this Structure== | ==About this Structure== | ||
| - | + | Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2AXB OCA]. | |
==Reference== | ==Reference== | ||
Stabilizing contributions of sulfur-modified nucleotides: crystal structure of a DNA duplex with 2'-O-[2-(methoxy)ethyl]-2-thiothymidines., Diop-Frimpong B, Prakash TP, Rajeev KG, Manoharan M, Egli M, Nucleic Acids Res. 2005 Sep 16;33(16):5297-307. Print 2005. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/16170156 16170156] | Stabilizing contributions of sulfur-modified nucleotides: crystal structure of a DNA duplex with 2'-O-[2-(methoxy)ethyl]-2-thiothymidines., Diop-Frimpong B, Prakash TP, Rajeev KG, Manoharan M, Egli M, Nucleic Acids Res. 2005 Sep 16;33(16):5297-307. Print 2005. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/16170156 16170156] | ||
| - | [[Category: Protein complex]] | ||
[[Category: Diop-Frimpong, B.]] | [[Category: Diop-Frimpong, B.]] | ||
[[Category: Egli, M.]] | [[Category: Egli, M.]] | ||
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[[Category: Prakash, T P.]] | [[Category: Prakash, T P.]] | ||
[[Category: Rajeev, K G.]] | [[Category: Rajeev, K G.]] | ||
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| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 19:35:14 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 16:35, 3 May 2008
Crystal Structure Analysis Of A 2-O-[2-(methoxy)ethyl]-2-thiothymidine Modified Oligodeoxynucleotide Duplex
Overview
Substitution of oxygen atoms by sulfur at various locations in the nucleic acid framework has led to analogs such as the DNA phosphorothioates and 4'-thio RNA. The phosphorothioates are excellent mimics of DNA, exhibit increased resistance to nuclease degradation compared with the natural counterpart, and have been widely used as first-generation antisense nucleic acid analogs for applications in vitro and in vivo. The 4'-thio RNA analog exhibits significantly enhanced RNA affinity compared with RNA, and shows potential for incorporation into siRNAs. 2-Thiouridine (s2U) and 5-methyl-2-thiouridine (m5s2U) are natural nucleotide analogs. s2U in tRNA confers greater specificity of codon-anticodon interactions by discriminating more strongly between A and G compared with U. 2-Thio modification preorganizes the ribose and 2'-deoxyribose sugars for a C3'-endo conformation, and stabilizes heteroduplexes composed of modified DNA and complementary RNA. Combination of the 2-thio and sugar 2'-O-modifications has been demonstrated to boost both thermodynamic stability and nuclease resistance. Using the 2'-O-[2-(methoxy)ethyl]-2-thiothymidine (m5s2Umoe) analog, we have investigated the consequences of the replacement of the 2-oxygen by sulfur for base-pair geometry and duplex conformation. The crystal structure of the A-form DNA duplex with sequence GCGTAT*ACGC (T* = m5s2Umoe) was determined at high resolution and compared with the structure of the corresponding duplex with T* = m5Umoe. Notable changes as a result of the incorporation of sulfur concern the base-pair parameter 'opening', an improvement of stacking in the vicinity of modified nucleotides as measured by base overlap, and a van der Waals interaction between sulfur atoms from adjacent m5s2Umoe residues in the minor groove. The structural data indicate only minor adjustments in the water structure as a result of the presence of sulfur. The observed small structural perturbations combined with the favorable consequences for pairing stability and nuclease resistance (when combined with 2'-O-modification) render 2-thiouracil-modified RNA a promising candidate for applications in RNAi.
About this Structure
Full crystallographic information is available from OCA.
Reference
Stabilizing contributions of sulfur-modified nucleotides: crystal structure of a DNA duplex with 2'-O-[2-(methoxy)ethyl]-2-thiothymidines., Diop-Frimpong B, Prakash TP, Rajeev KG, Manoharan M, Egli M, Nucleic Acids Res. 2005 Sep 16;33(16):5297-307. Print 2005. PMID:16170156 Page seeded by OCA on Sat May 3 19:35:14 2008
