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| [[Image:1fix.gif|left|200px]]<br />
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| <applet load="1fix" size="450" color="white" frame="true" align="right" spinBox="true"
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| caption="1fix, resolution 2.300Å" />
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| '''THE STRUCTURE OF AN RNA/DNA HYBRID: A SUBSTRATE OF THE RIBONUCLEASE ACTIVITY OF HIV-1 REVERSE TRANSCRIPTASE'''<br />
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| ==Overview== | | ==THE STRUCTURE OF AN RNA/DNA HYBRID: A SUBSTRATE OF THE RIBONUCLEASE ACTIVITY OF HIV-1 REVERSE TRANSCRIPTASE== |
| The structure of a complementary hybrid duplex of RNA and DNA has been, determined by X-ray crystallography. A ten residue DNA oligonucleotide of, sequence 5'-G-G-C-G-C-C-C-G-A-A-3' was annealed to complementary RNA, (5'-u-u-c-g-g-g-c-g-c-c-3') and crystallized, producing tetragonal, crystals that diffract to 2.3 A resolution. The hybrid adopts a geometry, that is neither strictly A nor B-form, rather the helix possesses, qualities of both, reminiscent of spectroscopic descriptions of a hybrid, conformation, or H-form. All of the ribonucleotides maintain the C3'-endo, conformation seen in A-form, while both C3'-endo and C2'-endo, conformations are found in the deoxyribonucleotides. The minor groove, width (8.5 to 10.5 A) is intermediate between standard values for A (11 A), and B-form (7.4 A) DNA. The global parameters rise and base-pairs tilt (or, inclination) are like that of A-DNA, however the slide and x displacement, (Dx) are more like that of A-RNA, thus giving the hybrid a unique, conformation. In addition, the 10-mer crystallizes in a manner that allows, the formation of dimers that stack end-to-end, thereby providing a glimpse, of how an extended (20 base-pair) helix of RNA-DNA hybrid might appear., This duplex sequence was selected for study because it is specifically, recognized by the ribonuclease H function of HIV reverse transcriptase. A, structure of a substrate of this enzyme is of potential value in, understanding requirements for the selectivity of this important drug, target. The minor groove of the hybrid duplex, lined with the 2-OH of the, ribose rings, is the single distinguishing characteristic of the RNA/DNA, hybrid, undoubtedly an important structural feature conferring, selectivity.
| | <StructureSection load='1fix' size='340' side='right'caption='[[1fix]], [[Resolution|resolution]] 2.30Å' scene=''> |
| | | == Structural highlights == |
| ==About this Structure== | | <table><tr><td colspan='2'>[[1fix]] is a 2 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1FIX OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1FIX FirstGlance]. <br> |
| 1FIX is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/ ]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1FIX OCA].
| | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.3Å</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=1fix FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1fix OCA], [https://pdbe.org/1fix PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1fix RCSB], [https://www.ebi.ac.uk/pdbsum/1fix PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1fix ProSAT]</span></td></tr> |
| ==Reference== | | </table> |
| The structure of an RNA/DNA hybrid: a substrate of the ribonuclease activity of HIV-1 reverse transcriptase., Horton NC, Finzel BC, J Mol Biol. 1996 Dec 6;264(3):521-33. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=8969302 8969302]
| | __TOC__ |
| [[Category: Protein complex]] | | </StructureSection> |
| [[Category: Finzel, B.C.]] | | [[Category: Large Structures]] |
| [[Category: Horton, N.C.]]
| | [[Category: Finzel BC]] |
| [[Category: double helix]] | | [[Category: Horton NC]] |
| [[Category: hiv-1 primer binding site]] | |
| [[Category: right handed dna/rna hybrid]] | |
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| ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Thu Nov 8 14:03:17 2007''
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