Prokaryotic topoisomerase I (topo IA) can only relax negative supercoiled DNA, whereas eukaryotic topoisomerase I (topo IB) can introduce positive supercoils, separating the DNA of daughter chromosomes after DNA replication, and relax DNA. (wikipedia.org)
eukaryotic topoisomerase I and topoisomerase V). These enzymes are primarily responsible for relaxing positively and/or negatively supercoiled DNA, except for reverse gyrase, which can introduce positive supercoils into DNA. (embl.de)
This entry represents the C-terminal region of DNA topoisomerase I enzymes from eukaryotes (type IB enzymes). (embl.de)
The crystal structures of human topoisomerase I comprising the core and carboxyl-terminal domains in covalent and noncovalent complexes with 22-base pair DNA duplexes reveal an enzyme that 'clamps' around essentially B-form DNA. (embl.de)
Single-stranded4
The structure of topo III (see below) bound to single-stranded DNA (pdb id = 1I7D) shows how the HTH and Toprim domain are coordinated about the DNA. (wikipedia.org)
The topo III variant is likewise very interesting because it has zinc-binding motifs that is thought to bind single-stranded DNA. (wikipedia.org)
First, the single-stranded DNA binds domain III and I. The catalytic tyrosine cleaves the DNA backbone, creating a transient 5' phosphotyrosine intermediate. (wikipedia.org)
Unlike Topo IA enzymes, Topo IB enzymes do not require a single-stranded region of DNA or metal ions for their function. (embl.de)
Topological1
DNA topoisomerases regulate the number of topological links between two DNA strands (i.e. change the number of superhelical turns) by catalysing transient single- or double-strand breaks, crossing the strands through one another, then resealing the breaks. (wikipedia.org)
Catalytic1
This region covers both the catalytic core and the DNA-binding domains. (embl.de)
Enzymes1
In molecular biology Type I topoisomerases are enzymes that cut one of the two strands of double-stranded DNA, relax the strand, and reanneal the strand. (wikipedia.org)
Change1
Type IA topoisomerases change the linking number of a circular DNA strand by units of strictly 1. (wikipedia.org)
Domain2
The break is then separated, using domain II as a hinge, and a second duplex or strand of DNA is passed through. (wikipedia.org)
The core domain and the first eight residues of the carboxyl-terminal domain of the enzyme, including the active-site nucleophile tyrosine-723, share significant structural similarity with the bacteriophage family of DNA integrases. (embl.de)
Type1
Type IA topoisomerases, historically said to be found in prokaryotes, create a single break in DNA and pass a second strand or duplex through the break. (wikipedia.org)
Topo III2
The structure of topo III (see below) bound to single-stranded DNA (pdb id = 1I7D) shows how the HTH and Toprim domain are coordinated about the DNA. (wikipedia.org)
The topo III variant is likewise very interesting because it has zinc-binding motifs that is thought to bind single-stranded DNA. (wikipedia.org)
Circular2
Type IA topoisomerases change the linking number of a circular DNA strand by units of strictly 1. (wikipedia.org)
A prototype of the small virulent DNAcoliphages, it is composed of a single strand of supercoiled circular DNA, which on infection, is converted to a double-stranded replicative form by a host enzyme. (lookformedical.com)
Strands1
DNA TOPOISOMERASES that catalyze ATP-independent breakage of one of the two strands of DNA, passage of the unbroken strand through the break, and rejoining of the broken strand. (bvsalud.org)
Double-stranded3
Its virion contains linear double-stranded DNA, terminally redundant and circularly permuted. (lookformedical.com)
It consists of linear double-stranded DNA, terminally redundant, and non-permuted. (lookformedical.com)
A temperate coliphage, in the genus Mu-like viruses, family MYOVIRIDAE, composed of a linear, double-stranded molecule of DNA, which is able to insert itself randomly at any point on the host chromosome. (lookformedical.com)
Genes2
Although having no detectable CYP1A1 or CYP1A2 activation, the untreated c14CoS/c14CoS mouse exhibits markedly elevated transcripts of the Nmo-1 gene and three growth arrest- and DNA damage-inducible (gadd) genes. (nih.gov)
This coordinated response to oxidative stress and DNA damage, by way of the release of a mammalian battery of genes from negative control, bears an interesting resemblance to the SOS response in bacteria. (nih.gov)
Hydrolysis2
The enzyme uses the hydrolysis of ATP to introduce positive supercoils and overwinds DNA, a feature attractive in hyperthermophiles, in which reverse gyrase is known to exist. (wikipedia.org)
Differences in the relative amounts of hydrolysis products and DNA adducts derived from anti- and syn-dihydrodiolepoxides following application of BP-7,8-diol to mouse skin in vivo indicate peroxyl radicals play a significant role in metabolism of BP-7,8-diol in uninduced animals. (nih.gov)
Strand3
topoisomerases II, IV and VI) break double-strand DNA. (wikipedia.org)
Type IA topoisomerases, historically said to be found in prokaryotes, create a single break in DNA and pass a second strand or duplex through the break. (wikipedia.org)
The break is then separated, using domain II as a hinge, and a second duplex or strand of DNA is passed through. (wikipedia.org)
Structure1
The folding of an organism's DNA molecule into a compact, orderly structure that fits within the limited space of a CELL or VIRUS PARTICLE. (lookformedical.com)
Cells2
In the case of aromatic amines, the electron-deficient derivatives are mutagenic to bacterial and mammalian cells. (nih.gov)