| http://purl.uniprot.org/citations/8631793 | http://www.w3.org/1999/02/22-rdf-syntax-ns#type | http://purl.uniprot.org/core/Journal_Citation |
| http://purl.uniprot.org/citations/8631793 | http://www.w3.org/2000/01/rdf-schema#comment | "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), a poorly conserved linker region (5 kDa), and the highly conserved COOH-terminal domain (8 kDa), which contains the active site tyrosine. To investigate this predicted domain organization, recombinant baculoviruses were engineered to express the 91-kDa full-length enzyme, a 70-kDa NH2-terminally truncated enzyme that is missing the first 174 residues, and a 58-kDa NH2- and COOH-terminally truncated core fragment encompassing residues 175-659. The specific activity of the full-length and Topo70 enzymes are indistinguishable from the native human Topo I purified from HeLa cells. Each protein is inhibited by camptothecin, topotecan, and 9-aminocamptothecin, but not by ATP. Activity is stimulated by Mg2+, Ba2+, Ca2+, Mn2+, spermine, and spermidine. The magnitude of the stimulatory effect of Mg2+ is inversely proportional to the salt concentration. Furthermore, at KCl concentrations of 300 mM or greater, the addition of Mg2+ is inhibitory. The effects of Mg2+ and the polycations spermine and spermidine are partially additive, an indication that the stimulatory mechanisms of the two substances are different. Activity was strongly inhibited or abolished by Ni2+, Zn2+, Cu2+, Cd2+, and Co2+. An examination of the hydrodynamic properties of full-length Topo I, Topo70, and Topo58 demonstrates that the core, linker, and COOH-terminal domains fold into a globular structure, while the NH2-terminal domain is highly extended. A comparison of the circular dichroism spectra of full-length Topo I and Topo70 demonstrates that residues 1-174 (approximately 21 kDa) of Topo I are largely if not completely unfolded. This observation is consistent with the fact that the NH2-terminal domain is dispensable for activity."xsd:string |
| http://purl.uniprot.org/citations/8631793 | http://purl.org/dc/terms/identifier | "doi:10.1074/jbc.271.13.7593"xsd:string |
| http://purl.uniprot.org/citations/8631793 | http://purl.uniprot.org/core/author | "Madden K.R."xsd:string |
| http://purl.uniprot.org/citations/8631793 | http://purl.uniprot.org/core/author | "Stewart L."xsd:string |
| http://purl.uniprot.org/citations/8631793 | http://purl.uniprot.org/core/author | "Ireton G.C."xsd:string |
| http://purl.uniprot.org/citations/8631793 | http://purl.uniprot.org/core/author | "Champoux J.J."xsd:string |
| http://purl.uniprot.org/citations/8631793 | http://purl.uniprot.org/core/author | "Parker L.H."xsd:string |
| http://purl.uniprot.org/citations/8631793 | http://purl.uniprot.org/core/date | "1996"xsd:gYear |
| http://purl.uniprot.org/citations/8631793 | http://purl.uniprot.org/core/name | "J Biol Chem"xsd:string |
| http://purl.uniprot.org/citations/8631793 | http://purl.uniprot.org/core/pages | "7593-7601"xsd:string |
| http://purl.uniprot.org/citations/8631793 | http://purl.uniprot.org/core/title | "Biochemical and biophysical analyses of recombinant forms of human topoisomerase I."xsd:string |
| http://purl.uniprot.org/citations/8631793 | http://purl.uniprot.org/core/volume | "271"xsd:string |
| http://purl.uniprot.org/citations/8631793 | http://www.w3.org/2004/02/skos/core#exactMatch | http://purl.uniprot.org/pubmed/8631793 |
| http://purl.uniprot.org/citations/8631793 | http://xmlns.com/foaf/0.1/primaryTopicOf | https://pubmed.ncbi.nlm.nih.gov/8631793 |
| http://purl.uniprot.org/uniprot/P11387#attribution-06FC08AD522772E6579AB71BB7F329A6 | http://purl.uniprot.org/core/source | http://purl.uniprot.org/citations/8631793 |