3ssf

<StructureSection load='3ssf' size='340' side='right' caption='[[3ssf]], [[Resolution|resolution]] 1.60&Aring;' scene=''>

<table><tr><td colspan='2'>[[3ssf]] is a 2 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3SSF OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3SSF FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene></td></tr>

<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[1pjo|1pjo]], [[1pjg|1pjg]], [[1jb8|1jb8]], [[1g4q|1g4q]]</td></tr>

<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3ssf FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3ssf OCA], [http://www.rcsb.org/pdb/explore.do?structureId=3ssf RCSB], [http://www.ebi.ac.uk/pdbsum/3ssf PDBsum]</span></td></tr>

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== Publication Abstract from PubMed ==

The crystal structure of an RNA/DNA hybrid dodecamer, r(5'-uaaaagaaaagg):d(5'-CCTTTTCTTTTA), which contains three-quarters of the polypurine tract (PPT) sequence of the HIV RNA genome is reported. The hybrid structure was determined at 1.6 A resolution and was found to have the A-form conformation. However, the presence of alternate conformations along the RNA template strand indicated increased flexibility of the PPT sequence. Two segments (at nucleotides 1-2 and 6-8) of the RNA chain have two conformations exhibiting differences in torsion and pseudorotation angles. For conformation I((1-2), (6-8)), 25% of the RNA sugars have the C2'-exo pucker and the rest have the expected C3'-endo pucker. The II(1-2) and II(6-8) conformations of the RNA strand have one sugar with the C2'-exo pucker. None of the ribose rings exist in the C2'-endo form, in contrast to a previous report which postulated a C2'-endo ribose as a key structural element of the PPT. The widths of the minor groove for conformations I((1-2), (6-8)) and II((1-2), (6-8)) of the RNA strand are 9.2-10.5 and 9.4-10.7 A, respectively. Both ranges are very close to the intervals accepted for A-form RNA duplexes. On the opposing DNA primer strand most of the sugars are C3'-endo, except for the 3'-terminal sugars, which are C2'-endo (T22) or O4'-endo (T23 and A24). The duplex includes a noncanonical u1(anti).A24(syn) base interaction with only one hydrogen bond between the bases. This noncanonical base interaction at the 5'-end of the template distorts the values of the helical parameters of the adjacent base pair.

Structure of an RNA/DNA dodecamer corresponding to the HIV-1 polypurine tract at 1.6 A resolution.,Drozdzal P, Michalska K, Kierzek R, Lomozik L, Jaskolski M Acta Crystallogr D Biol Crystallogr. 2012 Feb;68(Pt 2):169-75. Epub 2012 Jan 6. PMID:22281746<ref>PMID:22281746</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

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== References ==

<references/>

[[Category: Drozdzal, P]]

[[Category: Jaskolski, M]]

[[Category: Kierzek, R]]

[[Category: Lomozik, L]]

[[Category: Michalska, K]]

[[Category: Rna-dna hybrid]]