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Literature summary for 5.6.2.1 extracted from

  • Soe, K.; Hartung, S.; Grosse, F.
    Human topoisomerase I forms double cleavage complexes on natural DNA (2006), Biochem. Biophys. Res. Commun., 349, 178-185.
    View publication on PubMed
Search for more literature for 5.6.2.1

Inhibitors

Inhibitors Comment Organism Structure
camptothecin
-
 Homo sapiens
additional information to get a rough estimate of the preferred distance between two htopoI molecules a deoxyoligonucleotide with a defined length covalently attached (190 nts, the so-called suicide substrate L193s). Labelling of DNA attached to htopoI with 32P to determine the size of the attached DNA fragment more precisely Homo sapiens

Organism

Organism UniProt Comment Textmining
Homo sapiens
-
-
-

Purification (Commentary)

Purification (Comment) Organism
-
 Homo sapiens

Source Tissue

Source Tissue Comment Organism Textmining
HeLa-S3 cell htopoI obtained from HeLa S3 cells Homo sapiens
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
DNA so-called suicide substrate, contains a htopoI preferential binding sequence and is designed to trap the liberated 5'-OH end Homo sapiens DNA
-
 ?

Subunits

Subunits Comment Organism
monomer usually works as a monomer, previously shown that two molecules can form a dimer-like protein-protein complex on a suicide DNA substrate resulting in a topoisomerase I double cleavage complex. Here human topoisomerase I forms a transient dimer. Probably human topoisomerase I double cleavage complexes are part of the normal catalytic cycle of this enzyme that occur in vitro and possibly also in vivo Homo sapiens

Synonyms

Synonyms Comment Organism
DNA topoisomerase I
-
 Homo sapiens
hTopoI htopoI readily and very efficiently forms double cleavage complexes after the relaxation of negatively supercoiled plasmid DNA both with recombinant enzyme and with purified htopoI. When topo I is isolated from HeLa S3 cells, a considerable fraction migrates to the same gel electrophoretic position as topo I bearing a covalently bound 13-mer oligonucleotide. This may suggest that double cleavage complexes also form under intracellular conditions Homo sapiens
Topoisomerase I
-
 Homo sapiens

Ki Value [mM]

Ki Value [mM] Ki Value maximum [mM] Inhibitor Comment Organism Structure
0.000063
-
 camptothecin with 0.63 microM camptothecin or more numerous shifted htopoI bands detected Homo sapiens