DNA helicases
Helicases are essential components of a number of multiprotein complexes, including those that regulate transcription, splicing, translation, and DNA repair. These enzymes assist in the unwinding of double-stranded DNA and RNA as an essential part of their function.
Helicases are essential components of a number of multiprotein complexes, including those that regulate transcription, splicing, translation, and DNA repair. These enzymes assist in the unwinding of double-stranded DNA and RNA as an essential part of their function.
During DNA replication, DNA helicases separate the complementary DNA strands; this process of unwinding produces torsional stress in the DNA, which is relieved by topoisomerases. It would not be surprising, therefore, if DNA helicases were to operate in close conjuction with topoisomerases.
This has been shown for certain RecQ helicases. For example, E.coli RecQ helicase can unwind a covalently-closed double-stranded DNA substrate, and this activity stimulates E.coli topoisomerase III to fully catenate (interlink) two or more plasmid molecules.
Types
RecQ helicases
Pif1p subfamily of helicases
Pathology
DNA helicase deficiencies
See also
References
Cozzarelli NR, Cost GJ, Nollmann M, Viard T, Stray JE. Giant proteins that move DNA: bullies of the genomic playground. Nat Rev Mol Cell Biol. 2006 Aug;7(8):580-8. PMID: 16936698
Mohaghegh P, Hickson ID. DNA helicase deficiencies associated with cancer predisposition and premature ageing disorders. Hum Mol Genet. 2001 Apr;10(7):741-6. PMID: 11257107
Bessler JB, Torredagger JZ, Zakian VA. The Pif1p subfamily of helicases: region-specific DNA helicases? Trends Cell Biol. 2001 Feb;11(2):60-5. PMID: 11166213
Villani, G. and Tanguy Le Gac, N. Interactions of DNA helicases with damaged DNA: possible biological consequences. J. Biol. Chem. 275: 33185-33188, 2000
Chakraverty, R.K. and Hickson, I.D. Defending genome integrity during DNA replication: a proposed role for RecQ family helicases. Bioessays 21:286-294, 1999
Karow, J.K., Wu, L. and Hickson, I.D. RecQ family helicases: roles in cancer and aging. Curr. Opin. Genet. Dev. 10:32-38, 2000
Lohman, T.M. and Bjornson, K.P. Mechanisms of helicase-catalyzed DNA unwinding. Annu. Rev. Biochem. 65: 169-214, 1996
Seki, M., Miyazawa, H., Tada, S., Yanagisawa, J., Yamaoka, T., Hoshino, S., Ozawa, K., Eki, T., Nogami, M., Okumura, K. et al. Molecular cloning of cDNA encoding human DNA helicase Q1 which has homology to Escherichia coli RecQ helicase and localization of the gene at chromosome 12p12. Nucleic Acids Res. 22: 4566-4573, 1994
Puranam, K.L. and Blackshear, P.J. Cloning and characterization of RECQL, a potential human homologue of the Escherichia coli DNA helicase RecQ. J. Biol. Chem. 269:29838-29845, 1994
Gorbalenya, A.E. and Koonin, E.V. Helicases: amino acid sequence comparisons and structure-function relationships. Curr. Opin. Struct. Biol. 3: 419-429, 1993
