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1pjo

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(New page: 200px<br /> <applet load="1pjo" size="450" color="white" frame="true" align="right" spinBox="true" caption="1pjo, resolution 1.10&Aring;" /> '''Crystal Structure o...)
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[[Image:1pjo.gif|left|200px]]<br />
 
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<applet load="1pjo" size="450" color="white" frame="true" align="right" spinBox="true"
 
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caption="1pjo, resolution 1.10&Aring;" />
 
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'''Crystal Structure of an RNA/DNA hybrid of HIV-1 PPT'''<br />
 
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==Overview==
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==Crystal Structure of an RNA/DNA hybrid of HIV-1 PPT==
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Retroviral conversion of single-stranded RNA into double-stranded DNA, requires priming for each strand. While host cellular t-RNA serves as, primer for the first strand, the viral polypurine tract (PPT) is primer, for the second. Therefore, polypurine tracts of retroviruses are essential, for viral replication by reverse transcriptase (RT). These purine tracts, are resistant to cleavage during first strand synthesis. In obtaining the, primer for second strand synthesis, the RNase H function of RT must cleave, the PPT exactly for in vivo transcription to proceed efficiently and, proper integration to occur. At the RNase H active site the protein makes, contacts primarily along the backbone, with hydrogen bonds to the, sugar-phosphate oxygen atoms. A high-resolution structure (1.10A) of the, first ten base-pairs of the RNA/DNA hybrid PPT, r-(c-a-a-a-g-a-a-a-a-g)/d-(C-T-T-T-T-C-T-T-T-G), contains the highly, deformable r-(a-g-a) steps found in retroviral polypurine tracts. This, r-(a-g-a) motif is utilized in the "unzipping" or unpairing of bases that, occurs when RT binds a malleable PPT. Another unusual feature found in our, high-resolution PPT structure is the sugar switch at RNA adenine 2. All, the RNA sugars are the expected C3'-endo, except sugar 2, which is, C2'-endo, characteristic of B-form sugars. This local A-to-B conversion, adversely affects the pattern of hydrogen bonds from protein to, sugar-phosphate backbone, disrupting the catalytic site. Disruption could, cause the enzyme to pause at the 5'-end of the PPT, leaving it intact., Pyrimidine-purine (YR) steps are most deformable and the T-A step, especially can undergo A-to-B transitions readily.
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<StructureSection load='1pjo' size='340' side='right'caption='[[1pjo]], [[Resolution|resolution]] 1.10&Aring;' scene=''>
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== Structural highlights ==
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==About this Structure==
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<table><tr><td colspan='2'>[[1pjo]] is a 2 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1PJO OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1PJO FirstGlance]. <br>
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1PJO is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/ ] with MG as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1PJO OCA].
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</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.1&#8491;</td></tr>
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<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene></td></tr>
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==Reference==
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<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1pjo FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1pjo OCA], [https://pdbe.org/1pjo PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1pjo RCSB], [https://www.ebi.ac.uk/pdbsum/1pjo PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1pjo ProSAT]</span></td></tr>
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An unusual sugar conformation in the structure of an RNA/DNA decamer of the polypurine tract may affect recognition by RNase H., Kopka ML, Lavelle L, Han GW, Ng HL, Dickerson RE, J Mol Biol. 2003 Dec 5;334(4):653-65. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=14636594 14636594]
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</table>
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[[Category: Protein complex]]
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__TOC__
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[[Category: Dickerson, R.E.]]
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</StructureSection>
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[[Category: Han, G.W.]]
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[[Category: Large Structures]]
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[[Category: Kopka, M.L.]]
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[[Category: Dickerson RE]]
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[[Category: Lavelle, L.]]
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[[Category: Han GW]]
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[[Category: Ng, H.L.]]
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[[Category: Kopka ML]]
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[[Category: MG]]
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[[Category: Lavelle L]]
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[[Category: rna/dna hybrid; polypurine tract of hiv-1; moleuclar replacement; sugar conformation]]
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[[Category: Ng H-L]]
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''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Thu Nov 8 14:23:18 2007''
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Current revision

Crystal Structure of an RNA/DNA hybrid of HIV-1 PPT

PDB ID 1pjo

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