1z5t

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spinqualitylabelsall models 1z5t, resolution 1.600Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Crystal Structure of [d(CGCGAA(Z3dU)(Z3dU)CGCG)]2, Z3dU:5-(3-aminopropyl)-2'-deoxyuridine, in presence of thallium I.

Overview

Here, we describe the 1.6-A X-ray structure of the DDD (Dickerson-Drew, dodecamer), which has been covalently modified by the tethering of four, cationic charges. This modified version of the DDD, called here the, DDD(4+), is composed of [d(CGCGAAXXCGCG)](2), where X is effectively a, thymine residue linked at the 5 position to an n-propyl-amine. The, structure was determined from crystals soaked with thallium(I), which has, been broadly used as a mimic of K(+) in X-ray diffraction experiments, aimed at determining positions of cations adjacent to nucleic acids. Three, of the tethered cations are directed radially out from the DNA. The, radially directed tethered cations do not appear to induce structural, changes or to displace counterions. One of the tethered cations is, directed in the 3' direction, toward a phosphate group near one end of the, duplex. This tethered cation appears to interact electrostatically with, the DNA. This interaction is accompanied by changes in helical parameters, rise, roll, and twist and by a displacement of the backbone relative to a, control oligonucleotide. In addition, these interactions appear to be, associated with displacement of counterions from the major groove of the, DNA.

About this Structure

1Z5T is a Protein complex structure of sequences from [1] with SPM and TL as ligands. Full crystallographic information is available from OCA.

Reference

Structure of B-DNA with cations tethered in the major groove., Moulaei T, Maehigashi T, Lountos GT, Komeda S, Watkins D, Stone MP, Marky LA, Li JS, Gold B, Williams LD, Biochemistry. 2005 May 24;44(20):7458-68. PMID:15895989

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