Rabbit Polyclonal Antibody to TOP3B

Releases the supercoiling and torsional tension of DNA 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 than 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 By similarity. Possesses negatively supercoiled DNA relaxing activity.Ng S.-W., Nucleic Acids Res. 27:993-1000(1999).Kawasaki K., Genome Res. 7:250-261(1997).Collins J.E., Genome Biol. 5:RESEARCH84.1-RESEARCH84.11(2004).