2k95

Solution structure of the wild-type P2B-P3 pseudoknot of human telomerase RNA

spinqualitylabelsall models 2k95 Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2k95 is a 1 chain structure. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Solution NMR Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Telomerase is a ribonucleoprotein complex that replicates the 3' ends of linear chromosomes by successive additions of telomere repeat DNA. The telomerase holoenzyme contains two essential components for catalysis, a telomerase reverse transcriptase (TERT) and telomerase RNA (TER). The TER includes a template for telomere repeat synthesis as well as other domains required for function. We report the solution structure of the wild-type minimal conserved human TER pseudoknot refined with an extensive set of RDCs, and a detailed analysis of the effect of the bulge U177 on pseudoknot structure, dynamics analyzed by RDC and 13C relaxation measurements, and base pair stability. The overall structure of PKWT is highly similar to the previously reported DeltaU177 pseudoknot (PKDU) that has a deletion of a conserved bulge U important for catalytic activity. For direct comparison to PKWT, the structure of PKDU was re-refined with a comparable set of RDCs. Both pseudoknots contain a catalytically essential triple helix at the junction of the two stems, including two stem 1-loop 2 minor groove triples, a junction loop 1-loop 2 Hoogsteen base pair, and stem 2-loop 1 major groove U.A-U Watson-Crick-Hoogsteen triples located directly above the bulge U177. However, there are significant differences in the stabilities of base pairs near the bulge and the dynamics of some nucleotides. The stability of the base pairs in stem 2 surrounding the bulge U177 is greatly decreased, with the result that the Watson-Crick pairs in the triple helix begin to unfold before the Hoogsteen pairs, which may affect telomerase assembly and activity. The bulge U is positioned in the minor groove on the face opposite the triple helical interactions, and sterically blocks the A176 2'OH, which has recently been proposed to have a role in catalysis. The bulge U may serve as a hinge providing backbone flexibility in this region. Solution structure and dynamics of the wild-type pseudoknot of human telomerase RNA.,Kim NK, Zhang Q, Zhou J, Theimer CA, Peterson RD, Feigon J J Mol Biol. 2008 Dec 31;384(5):1249-61. Epub 2008 Oct 11. PMID:18950640 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Telomerase 3D structures

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