1jb8: Difference between revisions
New page: left|200px<br /> <applet load="1jb8" size="450" color="white" frame="true" align="right" spinBox="true" caption="1jb8, resolution 2.38Å" /> '''The Crystal Structu... |
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[[Image:1jb8.gif|left|200px]]<br /> | [[Image:1jb8.gif|left|200px]]<br /><applet load="1jb8" size="350" color="white" frame="true" align="right" spinBox="true" | ||
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caption="1jb8, resolution 2.38Å" /> | caption="1jb8, resolution 2.38Å" /> | ||
'''The Crystal Structure of an RNA/DNA Hybrid Reveals Novel Intermolecular Intercalation'''<br /> | '''The Crystal Structure of an RNA/DNA Hybrid Reveals Novel Intermolecular Intercalation'''<br /> | ||
==Overview== | ==Overview== | ||
An intermolecular intercalation of base pairs was found at the CA step in | 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. | ||
==About this Structure== | ==About this Structure== | ||
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:// | 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://oca.weizmann.ac.il/oca-bin/ocashort?id=1JB8 OCA]. | ||
==Reference== | ==Reference== | ||
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] | 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] | ||
[[Category: Protein complex]] | [[Category: Protein complex]] | ||
[[Category: Dickerson, R | [[Category: Dickerson, R E.]] | ||
[[Category: Han, G | [[Category: Han, G W.]] | ||
[[Category: Kopka, M | [[Category: Kopka, M L.]] | ||
[[Category: Langs, D.]] | [[Category: Langs, D.]] | ||
[[Category: dna/dna intercalation]] | [[Category: dna/dna intercalation]] | ||
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[[Category: rna/dna polypurine tract]] | [[Category: rna/dna polypurine tract]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:20:40 2008'' | ||
