Helicase: Difference between revisions

Helicase polarity, which is also deemed "directionality", is defined as the direction (characterized as 5'→3' or 3'→5') of helicase movement on the DNA/RNA single-strand along which it is moving. This determination of polarity is vital in f.ex. determining whether the tested helicase attaches to the DNA leading strand, or the DNA lagging strand. To characterize this helicase feature, a partially duplex DNA is used as the substrate that has a central single-strand DNA region with different lengths of duplex regions of DNA (one short region that runs 5'→3' and one longer region that runs 3'→5') on both sides of this region.<ref>{{cite book | vauthors = Borowiec JA | chapter = DNA Helicases| veditors = DePamphilis ML | title = DNA Replication in Eukaryotic Cells. | date = 1996 | publisher = Cold Spring Harbor Laboratory Press | location = Cold Spring Harbor, NY | pages = 545–574 | isbn = 978-0-87969-459-3 | oclc = 246537432 }}</ref> Once the helicase is added to that central single-strand region, the polarity is determined by characterization on the newly formed single-strand DNA.