| Structural highlights
Disease
[DNA2_HUMAN] Mitochondrial DNA deletion syndrome with progressive myopathy. The disease is caused by mutations affecting the gene represented in this entry. The disease is caused by mutations affecting the gene represented in this entry.
Function
[RFA1_HUMAN] Plays an essential role in several cellular processes in DNA metabolism including replication, recombination and DNA repair. Binds and subsequently stabilizes single-stranded DNA intermediates and thus prevents complementary DNA from reannealing.[1] [2] Functions as component of the alternative replication protein A complex (aRPA). aRPA binds single-stranded DNA and probably plays a role in DNA repair; it does not support chromosomal DNA replication and cell cycle progression through S-phase. In vitro, aRPA cannot promote efficient priming by DNA polymerase alpha but supports DNA polymerase delta synthesis in the presence of PCNA and replication factor C (RFC), the dual incision/excision reaction of nucleotide excision repair and RAD51-dependent strand exchange.[3] [4] [DNA2_HUMAN] Key enzyme involved in DNA replication and DNA repair in nucleus and mitochondrion. Involved in Okazaki fragments processing by cleaving long flaps that escape FEN1: flaps that are longer than 27 nucleotides are coated by replication protein A complex (RPA), leading to recruit DNA2 which cleaves the flap until it is too short to bind RPA and becomes a substrate for FEN1. Also involved in 5'-end resection of DNA during double-strand break (DSB) repair: recruited by BLM and mediates the cleavage of 5'-ssDNA, while the 3'-ssDNA cleavage is prevented by the presence of RPA. Also involved in DNA replication checkpoint independently of Okazaki fragments processing. Possesses different enzymatic activities, such as single-stranded DNA (ssDNA)-dependent ATPase, 5'-3' helicase and endonuclease activities. While the ATPase and endonuclease activities are well-defined and play a key role in Okazaki fragments processing and DSB repair, the 5'-3' DNA helicase activity is subject to debate. According to various reports, the helicase activity is weak and its function remains largely unclear. Helicase activity may promote the motion of DNA2 on the flap, helping the nuclease function.[5] [6] [7] [8] [9] [10] [11] [12]
Publication Abstract from PubMed
The Dna2 nuclease-helicase maintains genomic integrity by processing DNA double-strand breaks, Okazaki fragments and stalled replication forks. Dna2 requires ssDNA ends, and is dependent on the ssDNA-binding protein Rpa, which controls cleavage polarity. Here we present the 2.3 A structure of intact mouse Dna2 bound to a 15-nucleotide ssDNA. The nuclease active site is embedded in a long, narrow tunnel through which the DNA has to thread. The helicase domain is required for DNA binding but not threading. We also present the structure of a flexibly-tethered Dna2-Rpa interaction that recruits Dna2 to Rpa-coated DNA. We establish that a second Dna2-Rpa interaction is mutually exclusive with Rpa-DNA interactions and mediates the displacement of Rpa from ssDNA. This interaction occurs at the nuclease tunnel entrance and the 5' end of the Rpa-DNA complex. Hence, it only displaces Rpa from the 5' but not 3' end, explaining how Rpa regulates cleavage polarity.
Dna2 nuclease-helicase structure, mechanism and regulation by Rpa.,Zhou C, Pourmal S, Pavletich NP Elife. 2015 Oct 22;4. pii: e09832. doi: 10.7554/eLife.09832. PMID:26491943[13]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Mason AC, Haring SJ, Pryor JM, Staloch CA, Gan TF, Wold MS. An alternative form of replication protein a prevents viral replication in vitro. J Biol Chem. 2009 Feb 20;284(8):5324-31. doi: 10.1074/jbc.M808963200. Epub 2008, Dec 29. PMID:19116208 doi:10.1074/jbc.M808963200
- ↑ Kemp MG, Mason AC, Carreira A, Reardon JT, Haring SJ, Borgstahl GE, Kowalczykowski SC, Sancar A, Wold MS. An alternative form of replication protein a expressed in normal human tissues supports DNA repair. J Biol Chem. 2010 Feb 12;285(7):4788-97. doi: 10.1074/jbc.M109.079418. Epub 2009 , Dec 7. PMID:19996105 doi:10.1074/jbc.M109.079418
- ↑ Mason AC, Haring SJ, Pryor JM, Staloch CA, Gan TF, Wold MS. An alternative form of replication protein a prevents viral replication in vitro. J Biol Chem. 2009 Feb 20;284(8):5324-31. doi: 10.1074/jbc.M808963200. Epub 2008, Dec 29. PMID:19116208 doi:10.1074/jbc.M808963200
- ↑ Kemp MG, Mason AC, Carreira A, Reardon JT, Haring SJ, Borgstahl GE, Kowalczykowski SC, Sancar A, Wold MS. An alternative form of replication protein a expressed in normal human tissues supports DNA repair. J Biol Chem. 2010 Feb 12;285(7):4788-97. doi: 10.1074/jbc.M109.079418. Epub 2009 , Dec 7. PMID:19996105 doi:10.1074/jbc.M109.079418
- ↑ Kim JH, Kim HD, Ryu GH, Kim DH, Hurwitz J, Seo YS. Isolation of human Dna2 endonuclease and characterization of its enzymatic properties. Nucleic Acids Res. 2006 Apr 4;34(6):1854-64. Print 2006. PMID:16595799 doi:http://dx.doi.org/10.1093/nar/gkl102
- ↑ Masuda-Sasa T, Imamura O, Campbell JL. Biochemical analysis of human Dna2. Nucleic Acids Res. 2006 Apr 4;34(6):1865-75. Print 2006. PMID:16595800 doi:http://dx.doi.org/10.1093/nar/gkl070
- ↑ Zheng L, Zhou M, Guo Z, Lu H, Qian L, Dai H, Qiu J, Yakubovskaya E, Bogenhagen DF, Demple B, Shen B. Human DNA2 is a mitochondrial nuclease/helicase for efficient processing of DNA replication and repair intermediates. Mol Cell. 2008 Nov 7;32(3):325-36. doi: 10.1016/j.molcel.2008.09.024. PMID:18995831 doi:http://dx.doi.org/10.1016/j.molcel.2008.09.024
- ↑ Duxin JP, Dao B, Martinsson P, Rajala N, Guittat L, Campbell JL, Spelbrink JN, Stewart SA. Human Dna2 is a nuclear and mitochondrial DNA maintenance protein. Mol Cell Biol. 2009 Aug;29(15):4274-82. doi: 10.1128/MCB.01834-08. Epub 2009 Jun , 1. PMID:19487465 doi:http://dx.doi.org/10.1128/MCB.01834-08
- ↑ Nimonkar AV, Genschel J, Kinoshita E, Polaczek P, Campbell JL, Wyman C, Modrich P, Kowalczykowski SC. BLM-DNA2-RPA-MRN and EXO1-BLM-RPA-MRN constitute two DNA end resection machineries for human DNA break repair. Genes Dev. 2011 Feb 15;25(4):350-62. doi: 10.1101/gad.2003811. PMID:21325134 doi:http://dx.doi.org/10.1101/gad.2003811
- ↑ Fortini BK, Pokharel S, Polaczek P, Balakrishnan L, Bambara RA, Campbell JL. Characterization of the endonuclease and ATP-dependent flap endo/exonuclease of Dna2. J Biol Chem. 2011 Jul 8;286(27):23763-70. doi: 10.1074/jbc.M111.243071. Epub 2011, May 13. PMID:21572043 doi:http://dx.doi.org/10.1074/jbc.M111.243071
- ↑ Gloor JW, Balakrishnan L, Campbell JL, Bambara RA. Biochemical analyses indicate that binding and cleavage specificities define the ordered processing of human Okazaki fragments by Dna2 and FEN1. Nucleic Acids Res. 2012 Aug;40(14):6774-86. doi: 10.1093/nar/gks388. Epub 2012, May 7. PMID:22570407 doi:http://dx.doi.org/10.1093/nar/gks388
- ↑ Duxin JP, Moore HR, Sidorova J, Karanja K, Honaker Y, Dao B, Piwnica-Worms H, Campbell JL, Monnat RJ Jr, Stewart SA. Okazaki fragment processing-independent role for human Dna2 enzyme during DNA replication. J Biol Chem. 2012 Jun 22;287(26):21980-91. doi: 10.1074/jbc.M112.359018. Epub, 2012 May 7. PMID:22570476 doi:http://dx.doi.org/10.1074/jbc.M112.359018
- ↑ Zhou C, Pourmal S, Pavletich NP. Dna2 nuclease-helicase structure, mechanism and regulation by Rpa. Elife. 2015 Oct 22;4. pii: e09832. doi: 10.7554/eLife.09832. PMID:26491943 doi:http://dx.doi.org/10.7554/eLife.09832
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