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Title
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Crystal structure of NAD(+)-dependent DNA ligase: modular architecture and functional implications.
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Authors
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J.Y.Lee,
C.Chang,
H.K.Song,
J.Moon,
J.K.Yang,
H.K.Kim,
S.T.Kwon,
S.W.Suh.
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Ref.
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EMBO J, 2000,
19,
1119-1129.
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PubMed id
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Abstract
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DNA ligases catalyze the crucial step of joining the breaks in duplex DNA during
DNA replication, repair and recombination, utilizing either ATP or NAD(+) as a
cofactor. Despite the difference in cofactor specificity and limited overall
sequence similarity, the two classes of DNA ligase share basically the same
catalytic mechanism. In this study, the crystal structure of an NAD(+)-dependent
DNA ligase from Thermus filiformis, a 667 residue multidomain protein, has been
determined by the multiwavelength anomalous diffraction (MAD) method. It reveals
highly modular architecture and a unique circular arrangement of its four
distinct domains. It also provides clues for protein flexibility and DNA-binding
sites. A model for the multidomain ligase action involving large conformational
changes is proposed.
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