Human DNA topoisomerase I catalyzes the relaxation of both positive and negative supercoils without the requirement of energy. In addition to DNA replication and transcriptional activation, DNA topoisomerase I also plays a major role in pre-mRNA splicing, recombination, chromatin remodeling and other DNA or RNA templating activities. The C terminal domain of DNA topoisomerase I spanning from amino acids 713 to 765 is highly conserved and connected to the core domain by a poorly conserved linker domain (residues 636-713). An active site tyrosine has been characterized at position 723. Mutation of this tyrosine to phenylalanine at position 723 causes topo I to preferentially bind the supercoiled DNA rather than relaxed DNA in the mixture of supercoiled and relaxed DNA.
Forme physique
Clear and colorless frozen liquid solution
Notes préparatoires
Use a manual defrost freezer and avoid repeated freeze-thaw cycles. While working, please keep sample on ice.
Code de la classe de stockage
10 - Combustible liquids
Classe de danger pour l'eau (WGK)
WGK 1
Point d'éclair (°F)
Not applicable
Point d'éclair (°C)
Not applicable
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Science (New York, N.Y.), 279(5356), 1504-1513 (1998-03-21)
Topoisomerases I promote the relaxation of DNA superhelical tension by introducing a transient single-stranded break in duplex DNA and are vital for the processes of replication, transcription, and recombination. The crystal structures at 2.1 and 2.5 angstrom resolution of reconstituted
DNA topoisomerase poisons as antitumor drugs.
L F Liu
Annual review of biochemistry, 58, 351-375 (1989-01-01)
Annual review of biochemistry, 70, 369-413 (2001-06-08)
DNA topoisomerases solve the topological problems associated with DNA replication, transcription, recombination, and chromatin remodeling by introducing temporary single- or double-strand breaks in the DNA. In addition, these enzymes fine-tune the steady-state level of DNA supercoiling both to facilitate protein
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