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PDBsum entry 4ddx
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References listed in PDB file
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Key reference
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Title
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Crystal structures of thermotoga maritima reverse gyrase: inferences for the mechanism of positive DNA supercoiling.
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Authors
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M.G.Rudolph,
Y.Del toro duany,
S.P.Jungblut,
A.Ganguly,
D.Klostermeier.
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Ref.
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Nucleic Acids Res, 2013,
41,
1058-1070.
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PubMed id
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Abstract
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Reverse gyrase is an ATP-dependent topoisomerase that is unique to
hyperthermophilic archaea and eubacteria. The only reverse gyrase structure
determined to date has revealed the arrangement of the N-terminal helicase
domain and the C-terminal topoisomerase domain that intimately cooperate to
generate the unique function of positive DNA supercoiling. Although the
structure has elicited hypotheses as to how supercoiling may be achieved, it
lacks structural elements important for supercoiling and the molecular mechanism
of positive supercoiling is still not clear. We present five structures of
authentic Thermotoga maritima reverse gyrase that reveal a first view of two
interacting zinc fingers that are crucial for positive DNA supercoiling. The
so-called latch domain, which connects the helicase and the topoisomerase
domains is required for their functional cooperation and presents a novel fold.
Structural comparison defines mobile regions in parts of the helicase domain,
including a helical insert and the latch that are likely important for DNA
binding during catalysis. We show that the latch, the helical insert and the
zinc fingers contribute to the binding of DNA to reverse gyrase and are uniquely
placed within the reverse gyrase structure to bind and guide DNA during strand
passage. A possible mechanism for positive supercoiling by reverse gyrases is
presented.
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