Human DNA topoisomerase I is the best studied of the DNA topoisomerase family. It 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, cell cycle and other gene regulatory pathways during cell growth and development. The core domain spanning from amino acids 215 to 636 is highly conserved and retains DNA binding activity. Topo I has been found to nick the DNA with a preference of 5′-(A/T)(G/C)(A/T)T-3′. Camptothecin and its analogs have been tested as potent anticancer compounds by stabilizing topo I-DNA complex, thereby inhibiting both DNA and RNA synthesis.
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Clear and colorless frozen liquid solution
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Use a manual defrost freezer and avoid repeated freeze-thaw cycles. While working, please keep sample on ice.
The Journal of biological chemistry, 271(13), 7593-7601 (1996-03-29)
Amino acid sequence comparisons of human topoisomerase I (Topo I) with seven other cellular Topo I enzymes reveal that the enzyme can be divided into four major domains: the unconserved NH2-terminal domain (24 kDa), the conserved core domain (54 kDa)
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
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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