DNA helicase is an enzyme responsible for the separation of two annealed strands of nucleic acids. It binds to the double stranded DNA, and breaks the hydrogen bonds between the strands. This process allows a single-stranded DNA to form and be used as a template during transcription. ATP hydrolysis provides the energy for the enzyme to translocate along the double helix and generate a replication fork.
In E. coli DNA helicase is called the DnaB protein, and it differs slightly in the way it carries out it's function. DnaB forms a three-fold ring structure, with the lagging strand binding in the central region, whilst the leading strand is excluded. The DnaB translocates through a mechanism where dNTP's bind and cause a conformational change, forcing the DNA strands to separate.
Approximately 1% of eukaryotic genes code for helicases. The human genome codes for 95 non-redundant helicases: 64 RNA helicases and 31 DNA helicases.
- ↑ Kitao, Saori et. al. 1998. Cloning of Two New Human Helicase Genes of the RecQ Family: Biological Significance of Multiple Species in Higher Eukaryotes. Genomics 54: 443-452.
- ↑ Alberts, Johnson, Lewis, Raff, Roberts, Walters. (2008) Molecular Biology of the Cell: 273, 5th edition, New York: Garland Science.
- ↑ Alberts, Johnson, Lewis, Raff, Roberts, Walters. (2008) Molecular Biology of the Cell: 283, 5th edition, New York: Garland Science.