Type II topoisomerase

  • CAS Number: 142805-56-9

Topoisomerase II is an enzyme selected from the group of topoisomerases, which is found in all organisms and can loosen and dissolve helix turns of double-stranded DNA strands. A special feature of the bacterial topoisomerase ( gyrase ); they is able to introduce additional windings in a DNA strand. For their catalytic function of topoisomerase II needs in contrast to topoisomerase I energy in the form of ATP.

There are two subfamilies can be distinguished:

  • Mammals: topoisomerase II alpha and II beta
  • Yeast: topoisomerase II
  • Drosophila: topoisomerase II
  • Bacteria: gyrase, topoisomerase IV
  • Phage T4: DNA topoisomerase

The molecular weight of the enzyme, depending on the type of organism 160-180 kDa. Is a dimeric enzyme that consists of two monomers. A monomer can be divided into three domains: the N -terminal domain, central domain and C -terminal domain.

The N-terminal domain is composed of about 660 amino acids and is the binding of ATP. The central domain is composed of approximately 1200 amino acids and contains a tyrosine residue, which is responsible for the " cutting " of the DNA. One speaks here of the catalytic domain. The C -terminal domain varies in length and consists of many charged amino acids. It contains a NLS motif ( nuclear localization signal). This domain is also partially phosphorylated. The exact function of this domain has yet to be clarified.

In practice, above all gyrase inhibitor of interest. These are used as antibiotics. Among the best known among them include, for example, ciprofloxacin and novobiocin.

Anthracyclines are chemotherapeutic agents that are used against various types of cancer, especially breast cancer. Anthracyclines act by binding to topoisomerase IIα and thus inhibit cell division.

Swell

  • Isomerase
  • Genetics
CAS registry number DNA gyrase Adenosine triphosphate Dimer (chemistry)
780029
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