4cei

From Proteopedia

Revision as of 06:14, 23 April 2014

Template:STRUCTURE 4cei

Crystal structure of ADPNP-bound AddAB with a forked DNA substrate

Template:ABSTRACT PUBMED 24670664

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]} [ADDB_BACSU] The heterodimer acts as both an ATP-dependent DNA helicase and an ATP-dependent single-stranded exonuclease, acting in both directions. 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' to 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 AddB nuclease domain is not required for chi fragment generation; this subunit has 5' -> 3' nuclease activity. RecA thread formation during DNA double-strand break repair requires RecJ or AddAB.^{[4] [5] [6]}

About this Structure

4cei is a 3 chain structure with sequence from Bacsu. Full crystallographic information is available from OCA.

Reference

• Krajewski WW, Fu X, Wilkinson M, Cronin NB, Dillingham MS, Wigley DB. Structural basis for translocation by AddAB helicase-nuclease and its arrest at chi sites. Nature. 2014 Mar 16. doi: 10.1038/nature13037. PMID:24670664 doi:http://dx.doi.org/10.1038/nature13037

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
4. ↑ 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
5. ↑ 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
6. ↑ 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