Which enzyme activity is associated with DNA polymerase?
Pol I possesses four enzymatic activities: A 5’3′ (forward) DNA-dependent DNA polymerase activity, requiring a 3′ primer site and a template strand. A 3’5′ (reverse) exonuclease activity that mediates proofreading. A 5’3′ (forward) exonuclease activity mediating nick translation during DNA repair.
What is a function of DNA polymerase I?
DNA Polymerase I, Bacterial DNA polymerase I of eubacteria functions in vivo to synthesize short stretches of DNA during excision repair and to remove RNA primers and fill the gaps between Okazaki fragments in lagging strand replication.
Which enzyme is a topoisomerase?
Any enzyme that cleaves only one strand of a DNA duplex and then reseals it is classified as a type I topoisomerase (Topo I). The Topo I from E. coli acts on negative, but not positive, supercoils. In contrast, Topo I enzymes from eukaryotic cells can remove both positive and negative supercoils.
What do the enzymes topoisomerase I and topoisomerase II have in common?
What do the enzymes topoisomerase I and topoisomerase II have in common? They both have nuclease activity. They both create double-strand DNA breaks. They both can create winding (tension) in an initially relaxed DNA molecule.
What is the difference between topoisomerase and gyrase?
DNA gyrase and topoisomerase IV are the two type II topoisomerases present in bacteria. Gyrase is involved primarily in supporting nascent chain elongation during replication of the chromosome, whereas topoisomerase IV separates the topologically linked daughter chromosomes during the terminal stage of DNA replication.
What is the purpose of Supercoiling?
DNA supercoiling is important for DNA packaging within all cells. Because the length of DNA can be thousands of times that of a cell, packaging this genetic material into the cell or nucleus (in eukaryotes) is a difficult feat. Supercoiling of DNA reduces the space and allows for DNA to be packaged.
What are the two components of Supercoiling?
Inside cells, supercoiling is partitioned into two components, superhelical tension and restrained supercoils.