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From Proteopedia
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http://www.jbc.org/content/281/27/18265.full | http://www.jbc.org/content/281/27/18265.full | ||
Revision as of 19:35, 13 February 2017
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Contents |
DNA Helicase
DNA Helicase is a complex, 14 chain structure that unwinds DNA in replication by cleaving the hydrogen bonds between the complementary nucleotides at the replication fork. It is present in both prokaryotes and eukaryotes.
Function
By cleaving the hydrogen bonds between the complementary nucleotides at the , Helicase allows DNA polymerase to access each DNA strand in replication. Aside from its part in DNA replication, it also functions to unwind DNA in repair, transcription, and recombination.
Disease
Malfunctioning helicase causes issues in each of its functions. In general, a malfunctioning helicase affects transcription. The helicase causes missense and nonsense substitutions, frameshift, and deletion mutations. Without helicase, the DNA helix remains locked with hydrogen bonds and DNA polymerase does not have access to either strand.
Cancer and Premature Aging
Helicase separates the two strands of DNA so other enzymes can repair the molecule. If helicase is malfunctioning and doesn't repair DNA, the genome may be replicated incorrectly or transcribed into proteins that fold differently than normal. The cell overall will be affected, which can lead to the unchecked division indicative of cancer.
Structural highlights
There are several ligands that bind the various chains together in order to create Helicase. In various places throughout Helicase, a acts as a ligand.
References
https://www.ncbi.nlm.nih.gov/pubmed/11701636; http://www.jbc.org/content/281/27/18265.full
