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| [[Image:1jb8.gif|left|200px]]<br />
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| <applet load="1jb8" size="450" color="white" frame="true" align="right" spinBox="true"
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| caption="1jb8, resolution 2.38Å" />
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| '''The Crystal Structure of an RNA/DNA Hybrid Reveals Novel Intermolecular Intercalation'''<br />
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| ==Overview== | | ==The Crystal Structure of an RNA/DNA Hybrid Reveals Novel Intermolecular Intercalation== |
| An intermolecular intercalation of base pairs was found at the CA step in, the I222 crystal structure of the RNA.DNA hybrid, r(CAAAGAAAAG).d(CTTTTCTTTG), which contains two-thirds of the polypurine, tract sequence of HIV-1 with a substitution of cytosine for the initial, adenine. This sequence crystallized in both P212121 and I222 space groups, with an rms difference of only 0.63 A between residues 3 to 18 of the two, forms. P212121 and I222 helices are both A-like, but intercalation occurs, only in the I222 crystal form. The present structure shows bases stacked, in parallel rather than perpendicular as in intercalated DNA (I-DNA). The, base intercalation is also different from zipper-like meshing of bases, seen in the center of the crystal structure of d(GCGAAAGCT), which does, not have Watson-Crick base pairing. The base-step intercalation seen here, is reminiscent of domain swapping in proteins; therefore, we call this, phenomenon "base-pair swapping." It involves a highly mobile CA step and, seems to be sequence-specific and electrostatically stable without, disrupting Watson-Crick interactions. It also exhibits a large rise, concurrent with unwinding of the helix (low twist). We present a base-pair, swapping dimer in nucleic acids.
| | <StructureSection load='1jb8' size='340' side='right'caption='[[1jb8]], [[Resolution|resolution]] 2.38Å' scene=''> |
| | | == Structural highlights == |
| ==About this Structure== | | <table><tr><td colspan='2'>[[1jb8]] is a 2 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1JB8 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1JB8 FirstGlance]. <br> |
| 1JB8 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=1JB8 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]] 2.38Å</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=1jb8 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1jb8 OCA], [https://pdbe.org/1jb8 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1jb8 RCSB], [https://www.ebi.ac.uk/pdbsum/1jb8 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1jb8 ProSAT]</span></td></tr> |
| ==Reference== | | </table> |
| Crystal structure of an RNA.DNA hybrid reveals intermolecular intercalation: dimer formation by base-pair swapping., Han GW, Kopka ML, Langs D, Sawaya MR, Dickerson RE, Proc Natl Acad Sci U S A. 2003 Aug 5;100(16):9214-9. Epub 2003 Jul 18. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=12872000 12872000]
| | __TOC__ |
| [[Category: Protein complex]]
| | </StructureSection> |
| [[Category: Dickerson, R.E.]] | | [[Category: Large Structures]] |
| [[Category: Han, G.W.]] | | [[Category: Dickerson RE]] |
| [[Category: Kopka, M.L.]] | | [[Category: Han GW]] |
| [[Category: Langs, D.]] | | [[Category: Kopka ML]] |
| [[Category: dna/dna intercalation]] | | [[Category: Langs D]] |
| [[Category: rna/dna hybrid]] | |
| [[Category: rna/dna polypurine tract]] | |
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| ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Thu Nov 8 14:12:00 2007''
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