Activating Compound | Comment | Organism | Structure |
---|---|---|---|
1-ethylKuQuinone | synthesis of the pentacyclic-diquinoid synthetic compound, overview. It efficiently inhibits the cleavage step of the enzyme reaction fitting well into the catalytic site. When incubated with the binary topoisomerase-DNA cleaved complex, the compound helps the enzyme to remove itself from the cleaved DNA and close the DNA gap, increasing the religation rate. The compound also induces the religation of the stalled enzyme-camptothecin-DNA ternary complex. The religation enhancement is due to the presence on the compound of two oxygen atoms that act as hydrogen acceptors. This property facilitates the deprotonation of the 5 DNA end. Docking and molecular modeling, overview | Homo sapiens |
Cloned (Comment) | Organism |
---|---|
gene Top1, recombinant expression in Saccharomyces cerevisiae strain EKY3 from YCpGAL1-e-Top1 single copy plasmid, N-terminally epitope-tagged with sequence DYKDDDY | Homo sapiens |
Inhibitors | Comment | Organism | Structure |
---|---|---|---|
1-ethylKuQuinone | synthesis of the pentacyclic-diquinoid synthetic compound, overview. It efficiently inhibits the cleavage step of the enzyme reaction fitting well into the catalytic site. When incubated with the binary topoisomerase-DNA cleaved complex, the compound helps the enzyme to remove itself from the cleaved DNA and close the DNA gap, increasing the religation rate. Et-KuQ inhibits the relaxation activity of Top1. The compound also induces the religation of the stalled enzyme-camptothecin-DNA ternary complex. Docking and molecular modeling, overview | Homo sapiens | |
camptothecin | the natural compound reversibly binds the covalent Top1-DNA complex slowing down the religation of the cleaved DNA strand, thus inducing cell death | Homo sapiens | |
irinotecan | water-soluble camptothecin derivative | Homo sapiens | |
topotecan | water-soluble camptothecin derivative, topotecan mimics a DNA base-pair and binds at the site of DNA cleavage by intercalating between the upstream (?1) and downstream (+1) base-pairs interacting also with the enzyme, acting as an interfacial uncompetitive inhibitor | Homo sapiens |
Metals/Ions | Comment | Organism | Structure |
---|---|---|---|
Mg2+ | required | Homo sapiens |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Homo sapiens | - |
gene Top1 | - |
Purification (Comment) | Organism |
---|---|
N-terminally epitope-tagged with sequence DYKDDDY, i.e. FLAG-tag, recombinant enzyme from Saccharomyces cerevisiae strain EKY3 by immunoaffinity chromatography | Homo sapiens |
Reaction | Comment | Organism | Reaction ID |
---|---|---|---|
ATP-independent breakage of single-stranded DNA, followed by passage and rejoining | deprotonation of the 5' DNA end might be the limiting step in the topoisomerase religation mechanism | Homo sapiens |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
additional information | substrate is supercoiled plasmid DNA, and oligonucleotide substrate CL14 , 5'-GAAAAAAGACTTAG-3', annealed with CP25 complementary strand (5'-TAAAAATTTTTCTAAGTCTTTTTTC-3)', that is 5'-phosphorylated with unlabelled ATP | Homo sapiens | ? | - |
? |
Synonyms | Comment | Organism |
---|---|---|
DNA Top IB | - |
Homo sapiens |
Top1 | - |
Homo sapiens |
Topoisomerase I | - |
Homo sapiens |
Temperature Optimum [°C] | Temperature Optimum Maximum [°C] | Comment | Organism |
---|---|---|---|
37 | - |
assay at | Homo sapiens |
pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
---|---|---|---|
7.5 | - |
assay at | Homo sapiens |