1ss7 | pdb_00001ss7

Compensating bends in a 16 base-pair DNA oligomer containing a T3A3 segment

spinqualitylabelsall models 1ss7, 15 NMR models Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1ss7 is a 2 chain structure. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance. Related: 1ssv Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed In-phase ligated DNA containing T(n)A(n) segments fail to exhibit the retarded polyacrylamide gel electrophoresis (PAGE) migration observed for in-phase ligated A(n)T(n) segments, a behavior thought to be correlated with macroscopic DNA curvature. The lack of macroscopic curvature in ligated T(n)A(n) segments is thought to be due to cancellation of bending in regions flanking the TpA steps. To address this issue, solution-state NMR, including residual dipolar coupling (RDC) restraints, was used to determine a high-resolution structure of [d(CGAGGTTTAAACCTCG)2], a DNA oligomer containing a T3A3 tract. The overall magnitude and direction of bending, including the regions flanking the central TpA step, was measured using a radius of curvature, Rc, analysis. The Rc for the overall molecule indicated a small magnitude of global bending (Rc = 138 +/- 23 nm) towards the major groove, whereas the Rc for the two halves (72 +/- 33 nm and 69 +/- 14 nm) indicated greater localized bending into the minor groove. The direction of bending in the regions flanking the TpA step is in partial opposition (109 degrees), contributing to cancellation of bending. The cancellation of bending did not correlate with a pattern of roll values at the TpA step, or at the 5' and 3' junctions, of the T3A3 segment, suggesting a simple junction/roll model is insufficient to predict cancellation of DNA bending in all T(n)A(n) junction sequence contexts. Importantly, Rc analysis of structures refined without RDC restraints lacked the precision and accuracy needed to reliably measure bending. Compensating bends in a 16-base-pair DNA oligomer containing a T(3)A(3) segment: A NMR study of global DNA curvature.,McAteer K, Aceves-Gaona A, Michalczyk R, Buchko GW, Isern NG, Silks LA, Miller JH, Kennedy MA Biopolymers. 2004 Dec 15;75(6):497-511. PMID:15526287 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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