1g3a
From Proteopedia
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'''STRUCTURE OF RNA DUPLEXES (CIGCGICG)2''' | '''STRUCTURE OF RNA DUPLEXES (CIGCGICG)2''' | ||
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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=1G3A OCA]. | |
==Reference== | ==Reference== | ||
Stability and structure of RNA duplexes containing isoguanosine and isocytidine., Chen X, Kierzek R, Turner DH, J Am Chem Soc. 2001 Feb 21;123(7):1267-74. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/11456697 11456697] | Stability and structure of RNA duplexes containing isoguanosine and isocytidine., Chen X, Kierzek R, Turner DH, J Am Chem Soc. 2001 Feb 21;123(7):1267-74. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/11456697 11456697] | ||
| - | [[Category: Protein complex]] | ||
[[Category: Chen, X.]] | [[Category: Chen, X.]] | ||
[[Category: Kierzek, R.]] | [[Category: Kierzek, R.]] | ||
[[Category: Turner, D H.]] | [[Category: Turner, D H.]] | ||
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| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 17:05:03 2008'' | |
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Revision as of 14:05, 2 May 2008
STRUCTURE OF RNA DUPLEXES (CIGCGICG)2
Overview
Isoguanosine (iG) and isocytidine (iC) differ from guanosine (G) and cytidine (C), respectively, in that the amino and carbonyl groups are transposed. The thermodynamic properties of a set of iG, iC containing RNA duplexes have been measured by UV optical melting. It is found that iG-iC replacements usually stabilize duplexes, and the stabilization per iG-iC pair is sequence-dependent. The sequence dependence can be fit to a nearest-neighbor model in which the stabilities of iG--iC pairs depend on the adjacent iG--iC or G--C pairs. For 5'-CG-3'/3'-GC-5' and 5'-GG-3'/3'-CC-5' nearest neighbors, the free energy differences upon iG-iC replacement are smaller than 0.2 kcal/mol at 37 degrees C, regardless of the number of replacements. For 5'-GC-3'/3'-CG-5', however, each iG--iC replacement adds 0.6 kcal/mol stabilizing free energy at 37 degrees C. Stacking propensities of iG and iC as unpaired nucleotides at the end of a duplex are similar to those of G and C. An NMR structure is reported for r(CiGCGiCG)(2) and found to belong to the A-form family. The structure has substantial deviations from standard A-form but is similar to published NMR and/or crystal structures for r(CGCGCG)(2) and 2'-O-methyl (CGCGCG)(2). These results provide benchmarks for theoretical calculations aimed at understanding the fundamental physical basis for the thermodynamic stabilities of nucleic acid duplexes.
About this Structure
Full crystallographic information is available from OCA.
Reference
Stability and structure of RNA duplexes containing isoguanosine and isocytidine., Chen X, Kierzek R, Turner DH, J Am Chem Soc. 2001 Feb 21;123(7):1267-74. PMID:11456697 Page seeded by OCA on Fri May 2 17:05:03 2008
