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PDBsum entry 2hvq
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References listed in PDB file
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Key reference
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Title
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Rna ligase structures reveal the basis for RNA specificity and conformational changes that drive ligation forward.
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Authors
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J.Nandakumar,
S.Shuman,
C.D.Lima.
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Ref.
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Cell, 2006,
127,
71-84.
[DOI no: ]
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PubMed id
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Abstract
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T4 RNA ligase 2 (Rnl2) and kinetoplastid RNA editing ligases exemplify a family
of RNA repair enzymes that seal 3'OH/5'PO(4) nicks in duplex RNAs via ligase
adenylylation (step 1), AMP transfer to the nick 5'PO(4) (step 2), and attack by
the nick 3'OH on the 5'-adenylylated strand to form a phosphodiester (step 3).
Crystal structures are reported for Rnl2 at discrete steps along this pathway:
the covalent Rnl2-AMP intermediate; Rnl2 bound to an adenylylated nicked duplex,
captured immediately following step 2; and Rnl2 at an adenylylated nick in a
state poised for step 3. These structures illuminate the stereochemistry of
nucleotidyl transfer and reveal how remodeling of active-site contacts and
conformational changes propel the ligation reaction forward. Mutational analysis
and comparison of nick-bound structures of Rnl2 and human DNA ligase I highlight
common and divergent themes of substrate recognition that can explain their
specialization for RNA versus DNA repair.
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Figure 1.
Figure 1. Three-Step Pathway of Nick Sealing by
ATP-Dependent Polynucleotide Ligases
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Figure 3.
Figure 3. Serial Remodeling of Contacts in the Rnl2 Active
Site in Synch with the Chemical Steps of Ligation
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The above figures are
reprinted
by permission from Cell Press:
Cell
(2006,
127,
71-84)
copyright 2006.
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