1qc0

<table><tr><td colspan='2'>[[1qc0]] is a 4 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1QC0 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1QC0 FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=NH4:AMMONIUM+ION'>NH4</scene></td></tr>

<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat"><div style='overflow: auto; max-height: 3em;'>[[1qcu|1qcu]]</div></td></tr>

<div style="background-color:#fffaf0;">

== Publication Abstract from PubMed ==

The structures of two RNA duplexes, whose sequences correspond to portions of the ColE1 plasmid copy control RNA I and RNA II, have been determined. Crystals containing the 18mers 5'-CA CCGUUGGUAGCGGUGC-3' and 5'-CACCGCUACCAACGGUGC-3' diffract to 1.20 A resolution while those containing the 19mers 5'-GCACCGUUGGUAGCGGUGC-3' and 5'-GCACCGCUACCAACGGUGC-3' diffract to 1.55 A resolution. Both duplexes are standard A form, with Watson-Crick base pairing throughout. Use of anisotropic atomic displacement factors in refinement of the 1.20 A structure dramatically improved refinement statistics, resulting in a final R(free) of 15.0% and a crystallographic R-factor of 11.6%. Perhaps surprisingly, these crystals of the 18 base pair RNA exhibit a 36-fold static disorder, resulting in a structure with a single sugar-phosphate backbone conformation and an averaged base composition at each residue. Since the sugar-phosphate backbone structure is identical in the 36 different nucleotides that are superimposed, there can be no sequence-dependent variation in the structure. The average ribose pucker amplitude is 45.8 degrees for the 18 base pair structure and 46.4 degrees for the 19 base pair structure; these values are respectively 19% and 20% larger than the average pucker amplitude reported from nucleoside crystal structures. A standard RNA water structure, based on analysis of the hydration of these crystal structures and that of the TAR RNA stem [Ippolito, J. A., and Steitz, T. A. (1998) Proc. Natl. Acad. Sci. U.S.A. 95, 9819-9824], has been derived, which has allowed us to predict water positions in lower resolution RNA crystal structures. We report a new RNA packing motif, in which three pro-S(p) phosphate oxygens interact with an ammonium ion.

Crystal structures of two plasmid copy control related RNA duplexes: An 18 base pair duplex at 1.20 A resolution and a 19 base pair duplex at 1.55 A resolution.,Klosterman PS, Shah SA, Steitz TA Biochemistry. 1999 Nov 9;38(45):14784-92. PMID:10555960<ref>PMID:10555960</ref>

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

</div>

<div class="pdbe-citations 1qc0" style="background-color:#fffaf0;"></div>

== References ==

<references/>

[[Category: Klosterman, P S]]

[[Category: Shah, S A]]

[[Category: Steitz, T A]]

[[Category: Rna]]