2acj
Crystal structure of the B/Z junction containing DNA bound to Z-DNA binding proteins
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OverviewOverview
Left-handed Z-DNA is a higher-energy form of the double helix, stabilized, by negative supercoiling generated by transcription or unwrapping, nucleosomes. Regions near the transcription start site frequently contain, sequence motifs favourable for forming Z-DNA, and formation of Z-DNA near, the promoter region stimulates transcription. Z-DNA is also stabilized by, specific protein binding; several proteins have been identified with low, nanomolar binding constants. Z-DNA occurs in a dynamic state, forming as a, result of physiological processes then relaxing to the right-handed B-DNA., Each time a DNA segment turns into Z-DNA, two B-Z junctions form. These, have been examined extensively, but their structure was unknown. Here we, describe the structure of a B-Z junction as revealed by X-ray, crystallography at 2.6 A resolution. A 15-base-pair segment of DNA is, stabilized at one end in the Z conformation by Z-DNA binding proteins, while the other end remains B-DNA. Continuous stacking of bases between, B-DNA and Z-DNA segments is found, with the breaking of one base pair at, the junction and extrusion of the bases on each side (Fig. 1). These, extruded bases may be sites for DNA modification.
DiseaseDisease
Known diseases associated with this structure: Dyschromatosis symmetrica hereditaria OMIM:[601059]
About this StructureAbout this Structure
2ACJ is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of a junction between B-DNA and Z-DNA reveals two extruded bases., Ha SC, Lowenhaupt K, Rich A, Kim YG, Kim KK, Nature. 2005 Oct 20;437(7062):1183-6. PMID:16237447
Page seeded by OCA on Mon Nov 12 20:48:48 2007