1cy1

COMPLEX OF E.COLI DNA TOPOISOMERASE I WITH 5'PTPTPT

spinqualitylabelsall models 1cy1, resolution 2.30Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1cy1 is a 1 chain structure with sequence from Ecoli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: PO4, THP, TMP Related: 1cy0, 1cy2, 1cy4, 1cy6, 1cy7, 1cy8, 1cy9, 1cyy Activity: DNA topoisomerase, with EC number 5.99.1.2 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [TOP1_ECOLI] Releases the supercoiling and torsional tension of DNA, which is introduced during the DNA replication and transcription, by transiently cleaving and rejoining one strand of the DNA duplex. Introduces a single-strand break via transesterification at a target site in duplex DNA. The scissile phosphodiester is attacked by the catalytic tyrosine of the enzyme, resulting in the formation of a DNA-(5'-phosphotyrosyl)-enzyme intermediate and the expulsion of a 3'-OH DNA strand. The free DNA strand then undergoes passage around the unbroken strand, thus removing DNA supercoils. Finally, in the religation step, the DNA 3'-OH attacks the covalent intermediate to expel the active-site tyrosine and restore the DNA phosphodiester backbone. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed DNA topoisomerases are the enzymes responsible for controlling and maintaining the topological states of DNA. Type IA enzymes work by transiently breaking the phosphodiester backbone of one strand to allow passage of another strand through the break. The protein has to perform complex rearrangements of the DNA, and hence it is likely that different regions of the enzyme bind DNA with different affinities. In order to identify some of the DNA binding sites in the protein, we have solved the structures of several complexes of the 67 kDa N-terminal fragment of Escherichia coli DNA topoisomerase I with mono- and trinucleotides. There are five different binding sites in the complexes, one of which is adjacent to the active site. Two other sites are in the central hole of the protein and may represent general DNA binding regions. The positions of these sites allow us to identify different DNA binding regions and to understand their possible roles in the catalytic cycle. Protein-nucleotide interactions in E. coli DNA topoisomerase I.,Feinberg H, Changela A, Mondragon A Nat Struct Biol. 1999 Oct;6(10):961-8. PMID:10504732 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Topoisomerase

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