CRYSTAL STRUCTURE OF THE 30 KDA FRAGMENT OF E. COLI DNA TOPOISOMERASE I. MONOCLINIC FORMCRYSTAL STRUCTURE OF THE 30 KDA FRAGMENT OF E. COLI DNA TOPOISOMERASE I. MONOCLINIC FORM
Structural highlights
1cy9 is a 2 chain structure with sequence from Escherichia coli K-12. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
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.[1][2][3]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
↑Chen SJ, Wang JC. Identification of active site residues in Escherichia coli DNA topoisomerase I. J Biol Chem. 1998 Mar 13;273(11):6050-6. PMID:9497321
↑Zhu CX, Tse-Dinh YC. The acidic triad conserved in type IA DNA topoisomerases is required for binding of Mg(II) and subsequent conformational change. J Biol Chem. 2000 Feb 25;275(8):5318-22. PMID:10681504
↑Zhang Z, Cheng B, Tse-Dinh YC. Crystal structure of a covalent intermediate in DNA cleavage and rejoining by Escherichia coli DNA topoisomerase I. Proc Natl Acad Sci U S A. 2011 Apr 26;108(17):6939-44. Epub 2011 Apr 11. PMID:21482796 doi:http://dx.doi.org/10.1073/pnas.1100300108
