1esy

<StructureSection load='1esy' size='340' side='right'caption='[[1esy]], [[NMR_Ensembles_of_Models | 20 NMR models]]' scene=''>

<table><tr><td colspan='2'>[[1esy]] is a 1 chain structure. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1ESY OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1ESY FirstGlance]. <br>

</td></tr><tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[1bn0|1bn0]]</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=1esy FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1esy OCA], [http://pdbe.org/1esy PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1esy RCSB], [http://www.ebi.ac.uk/pdbsum/1esy PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1esy ProSAT]</span></td></tr>

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== Publication Abstract from PubMed ==

The genome of the human immunodeficiency virus type-1 (HIV-1) contains a stretch of approximately 120 nucleotides known as the psi-site that is essential for RNA packaging during virus assembly. These nucleotides have been proposed to form four stem-loops (SL1-SL4) that have both independent and overlapping functions. Stem-loop SL2 is important for efficient recognition and packaging of the full-length, unspliced viral genome, and also contains the major splice-donor site (SD) for mRNA splicing. We have determined the structure of the 19-residue SL2 oligoribonucleotide by heteronuclear NMR methods. The structure is generally consistent with the most recent of two earlier secondary structure predictions, with residues G1-G2-C3-G4 and C6-U7 forming standard Watson Crick base-pairs with self-complementary residues C16-G17-C18-C19 and A12-G13, respectively. However, residue A15, which is located near the center of the stem, does not form a predicted bulge, and residues A5 and U14 do not form an expected Watson-Crick base-pair. Instead, these residues form a novel A5-U14-A15 base-triple that appears to be stabilized by hydrogen bonds from A15-H61 and -H62 to A5-N1 and U14-O2, respectively; from A5-H61 to U14-O2, and from C16-H42 to U14-O2'. A kink in the backbone allows the aromatic rings of the sequential U14-A15 residues to be approximately co-planar, adopting a stable "platform motif" that is structurally similar to the A-A (adenosine) platforms observed in the P4-P6 ribozyme domain of the Tetrahymena group I intron. Platform motifs generally function in RNA by mediating long-range interactions, and it is therefore possible that the A-U-A base-triple platform mediates long-range interactions that either stabilize the psi-RNA or facilitate splicing and/or packaging. Residue G8 of the G8-G9-U10-G11 tetraloop is stacked above the U7-A12 base-pair, and the remaining tetraloop residues are disordered and available for potential interactions with either other RNA or protein components.

NMR structure of stem-loop SL2 of the HIV-1 psi RNA packaging signal reveals a novel A-U-A base-triple platform.,Amarasinghe GK, De Guzman RN, Turner RB, Summers MF J Mol Biol. 2000 May 26;299(1):145-56. PMID:10860728<ref>PMID:10860728</ref>

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

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<div class="pdbe-citations 1esy" style="background-color:#fffaf0;"></div>

== References ==

<references/>

[[Category: Amarasinghe, G K]]

[[Category: Guzman, R N.De]]

[[Category: Summers, M F]]

[[Category: Turner, R B]]

[[Category: Splice-donor site]]