420d

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=NA:SODIUM+ION'>NA</scene></td></tr>

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== Publication Abstract from PubMed ==

G.A mispairs are one of the most common noncanonical structural motifs of RNA. The 1.9 A resolution crystal structure of the RNA 16-mer r(GCAGAGUUAAAUCUGC)2 has been determined with two isolated or nonadjacent G.A mispairs. The molecule crystallizes with one duplex in the asymmetric unit in space group R3 and unit cell dimensions a = b = c = 49.24 A and alpha = beta = gamma = 51.2 degrees. It is the longest known oligonucleotide duplex at this resolution and isomorphous to the 16-mer duplex with the C.A+ mispairs [Pan, et al., (1998) J. Mol. Biol. 283, 977-984]. The C.A+ mispair behaves like a wobble pair while the G.A+ does not. The G.A mispairs are protonated at N1 of the adenines as in the C.A+ mispairs, and two hydrogen bonds in the G(syn).A+(anti) conformation are formed. The syn guanine is stabilized by an intranucleotide hydrogen bond between the 2-amino and the 5'-phosphate groups. The G(syn).A+(anti) conformation can provide a different surface for recognition in the grooves compared to other G.A hydrogen bonding schemes. The major groove is widened between the two mispairs allowing access to ligands. One of the 3-fold axes is occupied by a sodium ion and a water molecule, while a second is occupied by another water molecule.

Crystal structure of an RNA 16-mer duplex R(GCAGAGUUAAAUCUGC)2 with nonadjacent G(syn).A+(anti) mispairs.,Pan B, Mitra SN, Sundaralingam M Biochemistry. 1999 Mar 2;38(9):2826-31. PMID:10052954<ref>PMID:10052954</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 420d" style="background-color:#fffaf0;"></div>

== References ==

<references/>

[[Category: Mitra, S N]]

[[Category: Pan, B]]

[[Category: Sundaralingam, M]]

[[Category: Rna]]