Abstract：
:DNA helicases are required for virtually every aspect of DNA metabolism, including replication, repair, recombination and transcription. A comprehensive description of these essential biochemical processes requires detailed understanding of helicase mechanisms. These enzymes are ubiquitous, having been identified in viruses, prokaryotes and eukaryotes. Disease states, such as xeroderma pigmentosum, Cockayne's syndrome, Bloom's syndrome and Werner's syndrome, have been linked to defects in specific genes coding for DNA helicases. Helicases have been placed into different subfamilies based on sequence comparison. The largest subgroups are termed superfamily 1 and superfamily 2. A proposed mechanism for helicases in these classes has been described in terms of an 'inchworm model'. The inchworm model includes conformational changes driven by ATP binding and hydrolysis that allow unidirectional translocation along DNA. A monomeric form of the enzyme is proposed to have two DNA-binding sites that enable sequential steps of DNA binding and release. Significant differences exist between helicases in important aspects of the models such as the oligomerization state of the enzyme with some helicases functioning as monomers, some as dimers and others as higher-order oligomers.
journal_name
Nucleic Acids Resjournal_title
Nucleic acids researchauthors
Mackintosh SG,Raney KDdoi
10.1093/nar/gkl501subject
Has Abstractpub_date
2006-01-01 00:00:00pages
4154-9issue
15eissn
0305-1048issn
1362-4962pii
gkl501journal_volume
34pub_type
杂志文章,评审abstract：:ATP-dependent type I topoisomerases from extremely thermophilic archaebacteria--reverse gyrases--drive positive supercoiling of DNA. We showed that reverse gyrase from Desulfurococcus amylolyticus breaks the DNA at specific sites and covalently binds to the 5' end. In 30 out of 31 sites located in pBR322 DNA fragments...
journal_title：Nucleic acids research
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journal_title：Nucleic acids research
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journal_title：Nucleic acids research
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journal_title：Nucleic acids research
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journal_title：Nucleic acids research
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更新日期：2009-06-01 00:00:00
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更新日期：2004-02-23 00:00:00
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更新日期：2008-08-01 00:00:00
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更新日期：2013-07-01 00:00:00
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更新日期：1994-08-11 00:00:00
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journal_title：Nucleic acids research
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更新日期：1994-09-25 00:00:00
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更新日期：2004-06-04 00:00:00
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更新日期：2014-05-01 00:00:00
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更新日期：2009-04-01 00:00:00
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更新日期：1988-05-25 00:00:00
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更新日期：1979-02-01 00:00:00
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更新日期：2013-01-01 00:00:00
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更新日期：2014-03-01 00:00:00
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更新日期：2012-11-01 00:00:00
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更新日期：2010-01-01 00:00:00
