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405d
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(New page: 200px<br /><applet load="405d" size="350" color="white" frame="true" align="right" spinBox="true" caption="405d, resolution 2.50Å" /> '''STRUCTURE OF A 16-ME...)
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Revision as of 19:42, 29 January 2008
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STRUCTURE OF A 16-MER RNA DUPLEX R(GCAGACUUAAAUCUGC)2 WITH WOBBLE LIKE A.C MISMATCHES
Overview
The crystal structure of a 16-mer, the longest known RNA duplex, has been, determined at 2.5 A resolution. The hexadecamer r(GCAGACUUAAAUCUGC), contains isolated C.A/A.C mismatches with two hydrogen bonds. The two, hydrogen bonds in the mismatches suggests that N1 of A is protonated even, though the crystallization was done at neutral pH. Therefore, the C.A, mismatch is a C.A+ wobble similar to the G.U wobble. The two C.A+ pairs, are isolated by four Watson-Crick pairs and flanked by five Watson-Crick, base-pairs on either sides. Kinks/bends of 20 degrees are observed at the, wobble sites. The Watson-Crick base-pair A5.U26 on the 5'-side of the, first C6.A27(+) wobble has a twist angle of 27 degrees compared to the, 3'-side U7.A28 pair of 36 degrees. The twist angles are reversed (37, degrees and 26 degrees) in the second A11(+).C22 wobble because of the, approximate dyad in the molecule, the flanking base-pair sequences are A.U, pairs. The wobbles expand the major groove to 7.1 A/7.3 A. The duplexes, form helical columns and are tightly packed around the 31-screw axis. The, minor grooves of adjacent columns in juxtaposition interact through the, O2' atoms and the anionic phosphate oxygen atoms.Copyright 1998 Academic, Press.
About this Structure
405D is a Protein complex structure of sequences from [1]. Full crystallographic information is available from OCA.
Reference
Structure of a 16-mer RNA duplex r(GCAGACUUAAAUCUGC)2 with wobble C.A+ mismatches., Pan B, Mitra SN, Sundaralingam M, J Mol Biol. 1998 Nov 13;283(5):977-84. PMID:9799637
Page seeded by OCA on Tue Jan 29 21:42:14 2008
