Crystal structure of AddAB-DNA-ADPNP complex at 3 Angstrom resolutionCrystal structure of AddAB-DNA-ADPNP complex at 3 Angstrom resolution

Structural highlights

4cej is a 3 chain structure with sequence from Bacillus subtilis subsp. subtilis str. 168 and Synthetic construct. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Ligands:, ,
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

[ADDA_BACSU] An essential component of the DNA double-stranded break repair machinery, the heterodimer acts as both an ATP-dependent DNA helicase and an ATP-dependent, dual-direction single-stranded exonuclease. Recognizes the B.subtilis chi site (5'-AGCGG-3') which transforms the enzyme from a helicase which degrades both DNA strands to one with only 5' -> 3' exonuclease activity. This generates a double-stranded DNA with a protruding 3'-terminated single-stranded tail suitable for the initiation of homologous recombination (chi fragment). The AddA nuclease domain in particular is required for chi fragment generation; this subunit has 3' -> 5' nuclease and helicase activity. RecA thread formation during DNA double-strand break repair requires RecJ or AddAB.[1] [2] [3]

References

  1. Kooistra J, Haijema BJ, Venema G. The Bacillus subtilis addAB genes are fully functional in Escherichia coli. Mol Microbiol. 1993 Mar;7(6):915-23. PMID:8387145
  2. Chedin F, Ehrlich SD, Kowalczykowski SC. The Bacillus subtilis AddAB helicase/nuclease is regulated by its cognate Chi sequence in vitro. J Mol Biol. 2000 Apr 21;298(1):7-20. PMID:10756102 doi:http://dx.doi.org/10.1006/jmbi.2000.3556
  3. Yeeles JT, Dillingham MS. A dual-nuclease mechanism for DNA break processing by AddAB-type helicase-nucleases. J Mol Biol. 2007 Aug 3;371(1):66-78. Epub 2007 May 25. PMID:17570399 doi:http://dx.doi.org/10.1016/j.jmb.2007.05.053

4cej, resolution 3.00Å

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