133d

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spinqualitylabelsall models 133d, resolution 1.800Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

THE CRYSTAL STRUCTURE OF N4-METHYLCYTOSINE.GUANOSIN BASE-PAIRS IN THE SYNTHETIC HEXANUCLEOTIDE D(CGCGM(4)CG)

Overview

The structure of d(CGCGm4CG) were m4C = N4-methylcytosine has been determined by crystallographic methods. The crystals are multifaced prisms, with orthorhombic space group P2(1)2(1)2(1) and unit cell dimensions of a = 17.98, b = 30.77 and c = 44.75A. The asymmetric unit consists of one duplex of hexanucleotide and 49 waters. The R-factor is 0.189 for 1495 reflections with F > or = sigma(F) to a resolution limit of 1.8A. The double helix has a Z-DNA type structure which appears to be intermediate in structure to the two previously characterised structure types for Z-DNA hexamers. The two m4C.G base-pairs adopt structures that are very similar to those of the equivalent base-pairs in the structure of the native sequence d(CGCGCG) except for the presence of the methyl groups which are trans to the N3 atoms of their parent nucleotides and protrude into the solvent region. The introduction of the modified base-pairs into the d(CGCGCG) duplex appears to have a minimal effect on the overall base-pair morphology of the Z-DNA duplex.

About this Structure

133D is a Protein complex structure of sequences from [1]. Full crystallographic information is available from OCA.

Reference

The crystal structure of N4-methylcytosine.guanosine base-pairs in the synthetic hexanucleotide d(CGCGm4CG)., Cervi AR, Guy A, Leonard GA, Teoule R, Hunter WN, Nucleic Acids Res. 1993 Dec 11;21(24):5623-9. PMID:8284207

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