259d
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(New page: 200px<br /><applet load="259d" size="350" color="white" frame="true" align="right" spinBox="true" caption="259d, resolution 1.460Å" /> '''RNA HYDRATION: A DE...)
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Revision as of 15:49, 29 January 2008
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RNA HYDRATION: A DETAILED LOOK
Overview
The crystal structure of the RNA duplex [r(CCCCGGGG)]2 has been refined to, 1.46 A resolution with room temperature synchrotron diffraction data. This, represents the highest resolution reported to date for an all-RNA, oligonucleotide and is well beyond the best resolution ever achieved with, an A-form DNA duplex. The analysis of the ordered hydration around the, octamer duplex reveals conserved regular arrangements of water molecules, in both grooves. In the major groove, all located first shell water, molecules can be fitted into a pattern that is repeated through all eight, base pairs, involves half the phosphate oxygens, and joins the two, strands. In the minor groove, roughly across its narrowest dimension, tandem water molecules link the 2'-hydroxyl groups of adjacent nucleotides, in base-pair steps in a similarly regular fashion. The structure provides, evidence for an important role of the 2'-hydroxyl groups in the, thermodynamic stabilization of RNA, beyond their known functions of, locking the sugar pucker and mediating 3' --> 5' intrastrand O2'...O4', hydrogen bonds. The ribose 2'-hydroxyls lay the foundation for the, enthalpic stability of the RNA relative to the DNA duplex, both as a, scaffold for the water network in the minor groove and through their, extensive individual hydration.
About this Structure
259D is a Protein complex structure of sequences from [1]. Full crystallographic information is available from OCA.
Reference
RNA hydration: a detailed look., Egli M, Portmann S, Usman N, Biochemistry. 1996 Jul 2;35(26):8489-94. PMID:8679609
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