1al5: Difference between revisions
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'''A-TRACT RNA DODECAMER, NMR, 12 STRUCTURES'''<br /> | '''A-TRACT RNA DODECAMER, NMR, 12 STRUCTURES'''<br /> | ||
==Overview== | ==Overview== | ||
The thermodynamic stability of nine dodecamers (four DNA and five RNA) of | The thermodynamic stability of nine dodecamers (four DNA and five RNA) of the same base composition has been compared by UV-melting. TheDeltaG of stabilisation were in the order: r(GACUGAUCAGUC)2>r(CGCAAATTTGCG)2 approximately r(CGCAUAUAUGCG)2>d(CGCAAATTTGCG)2 approximately r(CGCAAAUUUGCG)2>d(CGCATATATGCG)2 approximately d(GACTGATCAGTC)2>r(CGCUUUAAAGCG)2 approximately d(CGCTTTAAAGCG)2. Compared with the mixed sequences, both r(AAAUUU) and r(UUUAAA) are greatly destablising in RNA, whereas in DNA, d(TTTAAA) is destabilising but d(AAATTT) is stabilising, which has been attributed to the formation of a special B'structure involving large propeller twists of the A-T base pairs. The solution structure of the RNA dodecamer r(CGCAAAUUUGCG)2has been determined using NMR and restrained molecular dynamics calculations to assess the conformational reasons for its stability in comparison with d(CGCAAATTTGCG)2. The structures refined to a mean pairwise r.m.s.d. of 0.89+/-0.29 A. The nucleotide conformations are typical of the A family of structures. However, although the helix axis displacement is approximately 4.6 A into the major groove, the rise (3.0 A) and base inclination ( approximately 6 degrees ) are different from standard A form RNA. The extensive base-stacking found in the AAATTT tract of the DNA homologue that is largely responsible for the higher thermodynamic stability of the DNA duplex is reduced in the RNA structure, which may account for its low relative stability. | ||
==About this Structure== | ==About this Structure== | ||
1AL5 is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/ ]. Full crystallographic information is available from [http:// | 1AL5 is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/ ]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1AL5 OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Protein complex]] | [[Category: Protein complex]] | ||
[[Category: Brown, T.]] | [[Category: Brown, T.]] | ||
[[Category: Conn, G | [[Category: Conn, G L.]] | ||
[[Category: Conte, M | [[Category: Conte, M R.]] | ||
[[Category: Lane, A | [[Category: Lane, A N.]] | ||
[[Category: ribonucleic acid]] | [[Category: ribonucleic acid]] | ||
[[Category: rna duplex]] | [[Category: rna duplex]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 11:45:42 2008'' | ||
Revision as of 12:45, 21 February 2008
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A-TRACT RNA DODECAMER, NMR, 12 STRUCTURES
OverviewOverview
The thermodynamic stability of nine dodecamers (four DNA and five RNA) of the same base composition has been compared by UV-melting. TheDeltaG of stabilisation were in the order: r(GACUGAUCAGUC)2>r(CGCAAATTTGCG)2 approximately r(CGCAUAUAUGCG)2>d(CGCAAATTTGCG)2 approximately r(CGCAAAUUUGCG)2>d(CGCATATATGCG)2 approximately d(GACTGATCAGTC)2>r(CGCUUUAAAGCG)2 approximately d(CGCTTTAAAGCG)2. Compared with the mixed sequences, both r(AAAUUU) and r(UUUAAA) are greatly destablising in RNA, whereas in DNA, d(TTTAAA) is destabilising but d(AAATTT) is stabilising, which has been attributed to the formation of a special B'structure involving large propeller twists of the A-T base pairs. The solution structure of the RNA dodecamer r(CGCAAAUUUGCG)2has been determined using NMR and restrained molecular dynamics calculations to assess the conformational reasons for its stability in comparison with d(CGCAAATTTGCG)2. The structures refined to a mean pairwise r.m.s.d. of 0.89+/-0.29 A. The nucleotide conformations are typical of the A family of structures. However, although the helix axis displacement is approximately 4.6 A into the major groove, the rise (3.0 A) and base inclination ( approximately 6 degrees ) are different from standard A form RNA. The extensive base-stacking found in the AAATTT tract of the DNA homologue that is largely responsible for the higher thermodynamic stability of the DNA duplex is reduced in the RNA structure, which may account for its low relative stability.
About this StructureAbout this Structure
1AL5 is a Protein complex structure of sequences from [1]. Full crystallographic information is available from OCA.
ReferenceReference
Conformational properties and thermodynamics of the RNA duplex r(CGCAAAUUUGCG)2: comparison with the DNA analogue d(CGCAAATTTGCG)2., Conte MR, Conn GL, Brown T, Lane AN, Nucleic Acids Res. 1997 Jul 1;25(13):2627-34. PMID:9185574
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