TAILIEUCHUNG - Báo cáo khoa học: Unraveling DNA helicases Motif, structure, mechanism and function

DNA helicases are molecular motor enzymes that use the energy of NTP hydrolysis to separate transiently energetic-ally stable duplex DNA into single strands. They are there-fore essential in nearly all DNA metabolic transactions. They act as essential molecular tools for the cellular machinery. Since the discovery of the first DNA helicase in Escherichia coliin1976, several havebeen isolated fromboth prokaryotic and eukaryotic systems. DNA helicases gener-ally bind to ssDNA or ssDNA/dsDNA junctions and translocate mainly unidirectionally along the bound strand anddisrupt the hydrogenbonds between the duplexes | Eur. J. Biochem. 271 1849-1863 2004 FEBS 2004 doi REVIEW ARTICLE Unraveling DNA helicases Motif structure mechanism and function Narendra Tuteja and Renu Tuteja International Centre for Genetic Engineering and Biotechnology ICGEB New Delhi India DNA helicases are molecular motor enzymes that use the energy of NTP hydrolysis to separate transiently energetically stable duplex DNA into single strands. They are therefore essential in nearly all DNA metabolic transactions. They act as essential molecular tools for the cellular machinery. Since the discovery of the first DNA helicase in Escherichia coli in 1976 several have been isolated from both prokaryotic and eukaryotic systems. DNA helicases generally bind to ssDNA or ssDNA dsDNA junctions and translocate mainly unidirectionally along the bound strand and disrupt the hydrogen bonds between the duplexes. Most helicases contain conserved motifs which act as an engine to drive DNA unwinding. Crystal structures have revealed an underlying common structural fold for their function. These structures suggest the role of the helicase motifs in catalytic function and offer clues as to how these proteins can translocate and unwind DNA. The genes containing helicase motifs may have evolved from a common ancestor. In this review we cover the conserved motifs structural information mechanism of DNA unwinding and translocation and functional aspects of DNA helicases. Keywords crystal structure DEAD-box protein DNA helicase helicase motifs unwinding enzyme. DNA helicases are motor proteins that can transiently catalyze the unwinding of energetically stable duplex DNA molecules using NTP hydrolysis as the source of energy 1 2 . They are important enzymatic tools for the cellular DNA machinery. They are known to play essential roles in nearly all aspects of nucleic acid metabolism such as DNA replication repair recombination and transcription. All helicases share at least three common biochemical .

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