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==STRUCTURE OF A DNA:RNA HYBRID DUPLEX: WHY RNASE H DOES NOT CLEAVE PURE RNA==
<StructureSection load='124d' size='340' side='right'caption='[[124d]]' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[124d]] is a 2 chain structure. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=124D OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=124D FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Solution NMR</td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=124d FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=124d OCA], [https://pdbe.org/124d PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=124d RCSB], [https://www.ebi.ac.uk/pdbsum/124d PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=124d ProSAT]</span></td></tr>
</table>
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== Publication Abstract from PubMed ==
The solution structure of the DNA:RNA hybrid duplex d(GTCACATG):r(caugugac) has been determined by means of two-dimensional nuclear Overhauser effect (2D-NOE) spectra, restrained molecular dynamics and full-relaxation matrix stimulation of the 2D-NOE spectra. The DNA:RNA hybrid duplex assumes neither an A-form nor a B-form structure in solution, but an intermediate heteromerous duplex structure. The sugars of the RNA strand have a normal N-type C3'-endo conformation, but the DNA strand sugars have neither N-type nor S-type conformations; instead, they have an unexpected intermediate O4'-endo conformation. The negative x-displacement, as well as the small rise and positive inclination of the base-pairs, resembles A-form morphology but the minor groove width is intermediate between that of A-form and B-form duplexes. Both the DNA and RNA strands show prominent sequence-dependent variations in their helical parameters. Combined analysis of NOE and J-coupling data indicates that the DNA sugars are not in a dynamical two-state equilibrium. The detailed three-dimensional structure of this DNA:RNA hybrid molecule leads to a proposed model for its interaction with RNase H. Several specific structural features of the enzyme complexed with the hybrid duplex appear to explain the mechanism whereby RNase H discriminates between DNA:RNA hybrid duplexes and pure RNA:RNA duplexes.

Structure of a DNA:RNA hybrid duplex. Why RNase H does not cleave pure RNA.,Fedoroff OYu, Salazar M, Reid BR J Mol Biol. 1993 Oct 5;233(3):509-23. PMID:8411159<ref>PMID:8411159</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 124d" style="background-color:#fffaf0;"></div>
== References ==
<references/>
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</StructureSection>
[[Category: Large Structures]]
[[Category: Fedoroff OY]]
[[Category: Reid BR]]
[[Category: Salazar M]]