Abstract:
:We report that diverse species of bacteria encode a type IB DNA topoisomerase that resembles vaccinia virus topoisomerase. Deinococcus radiodurans topoisomerase IB (DraTopIB), an exemplary member of this family, relaxes supercoiled DNA in the absence of a divalent cation or ATP. DraTopIB has a compact size (346 aa) and is a monomer in solution. Mutational analysis shows that the active site of DraTopIB is composed of the same constellation of catalytic side chains as the vaccinia enzyme. Sequence comparisons and limited proteolysis suggest that their folds are conserved. These findings imply an intimate evolutionary relationship between the poxvirus and bacterial type IB enzymes, and they engender a scheme for the evolution of topoisomerase IB and tyrosine recombinases from a common ancestral strand transferase in the bacterial domain. Remarkably, bacteria that possess topoisomerase IB appear to lack DNA topoisomerase III.
journal_name
Proc Natl Acad Sci U S Aauthors
Krogh BO,Shuman Sdoi
10.1073/pnas.032613199keywords:
subject
Has Abstractpub_date
2002-02-19 00:00:00pages
1853-8issue
4eissn
0027-8424issn
1091-6490pii
032613199journal_volume
99pub_type
杂志文章abstract::The use of matching variable number of tandem repeat (VNTR) profiles to link suspects with crimes is potentially very powerful, but it has been quite controversial. Initial debate over laboratory procedures has largely given way to debate over the statistical and population genetic issues involved in calculating the f...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:1983-03-01 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2010-04-20 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2002-04-16 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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pub_type: 杂志文章
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更新日期:1999-02-16 00:00:00