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</td></tr><tr id='NonStdRes'><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><scene name='pdbligand=I:INOSINIC+ACID'>I</scene></td></tr>

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== Publication Abstract from PubMed ==

The crystal structure of the RNA octamer duplex r(CCCIUGGG)2has been elucidated at 2.5 A resolution. The crystals belong to the space group P21and have unit cell constants a = 33.44 A, b = 43.41 A, c = 49.39 A and beta = 104.7 degrees with three independent duplexes (duplexes 1-3) in the asymmetric unit. The structure was solved by the molecular replacement method and refined to an Rwork/Rfree of 0.185/0.243 using 3765 reflections between 8.0 and 2.5 A. This is the first report of an RNA crystal structure incorporating I.U wobbles and three molecules in the asymmetric unit. Duplex 1 displays a kink of 24 degrees between the mismatch sites, while duplexes 2 and 3 have two kinks each of 19 degrees and 27 degrees, and 24 degrees and 29 degrees, respectively, on either side of the tandem mismatches. At the I.U/U.I mismatch steps, duplex 1 has a twist angle of 33.9 degrees, close to the average for all base pair steps, but duplexes 2 and 3 are underwound, with twist angles of 24.4 degrees and 26.5 degrees, respectively. The tandem I.U wobbles show intrastrand purine-pyrimidine stacking but exhibit interstrand purine-purine stacking with the flanking C.G pairs. The three independent duplexes are stacked non-coaxially in a head-to-tail fashion to form infinite pseudo-continuous helical columns which form intercolumn hydrogen bonding interactions through the 2'-hydroxyl groups where the minor grooves come together.

Crystal structure of an RNA octamer duplex r(CCCIUGGG)2 incorporating tandem I.U wobbles.,Pan B, Mitra SN, Sun L, Hart D, Sundaralingam M Nucleic Acids Res. 1998 Dec 15;26(24):5699-706. PMID:9838002<ref>PMID:9838002</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

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<div class="pdbe-citations 409d" style="background-color:#fffaf0;"></div>

== References ==

<references/>

[[Category: Hart, D]]

[[Category: Mitra, S N]]

[[Category: Pan, B]]

[[Category: Sun, L]]

[[Category: Sundaralingam, M]]

[[Category: Rna]]