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DNA helicases

Sunday 13 July 2003

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

- helicases
- RNA helicases

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