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|3p87, resolution 2.99Å ()|
Structure of human PCNA bound to RNASEH2B PIP box peptide
Ribonuclease H2 is the major nuclear enzyme degrading cellular RNA/DNA hybrids in eukaryotes and the sole nuclease known to be able to hydrolyze ribonucleotides misincorporated during genomic replication. Mutation in RNASEH2 causes Aicardi-Goutieres syndrome, an auto-inflammatory disorder that may arise from nucleic acid byproducts generated during DNA replication. Here, we report the crystal structures of Archaeoglobus fulgidus RNase HII in complex with PCNA, and human PCNA bound to a C-terminal peptide of RNASEH2B. In the archaeal structure, three binding modes are observed as the enzyme rotates about a flexible hinge while anchored to PCNA by its PIP-box motif. PCNA binding promotes RNase HII activity in a hinge-dependent manner. It enhances both cleavage of ribonucleotides misincorporated in DNA duplexes, and the comprehensive hydrolysis of RNA primers formed during Okazaki fragment maturation. In addition, PCNA imposes strand specificity on enzyme function, and by localizing RNase H2 and not RNase H1 to nuclear replication foci in vivo it ensures that RNase H2 is the dominant RNase H activity during nuclear replication. Our findings provide insights into how type 2 RNase H activity is directed during genome replication and repair, and suggest a mechanism by which RNase H2 may suppress generation of immunostimulatory nucleic acids.
PCNA directs type 2 RNase H activity on DNA replication and repair substrates., Bubeck D, Reijns MA, Graham SC, Astell KR, Jones EY, Jackson AP, Nucleic Acids Res. 2011 Jan 17. PMID:21245041
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
[RNH2B_HUMAN] Aicardi-Goutieres syndrome. The disease is caused by mutations affecting the gene represented in this entry.
[PCNA_HUMAN] Auxiliary protein of DNA polymerase delta and is involved in the control of eukaryotic DNA replication by increasing the polymerase's processibility during elongation of the leading strand. Induces a robust stimulatory effect on the 3'-5' exonuclease and 3'-phosphodiesterase, but not apurinic-apyrimidinic (AP) endonuclease, APEX2 activities. Has to be loaded onto DNA in order to be able to stimulate APEX2. Plays a key role in DNA damage response (DDR) by being conveniently positioned at the replication fork to coordinate DNA replication with DNA repair and DNA damage tolerance pathways. Acts as a loading platform to recruit DDR proteins that allow completion of DNA replication after DNA damage and promote postreplication repair: Monoubiquitinated PCNA leads to recruitment of translesion (TLS) polymerases, while 'Lys-63'-linked polyubiquitination of PCNA is involved in error-free pathway and employs recombination mechanisms to synthesize across the lesion.  [RNH2B_HUMAN] Non catalytic subunit of RNase H2, an endonuclease that specifically degrades the RNA of RNA:DNA hybrids. Participates in DNA replication, possibly by mediating the removal of lagging-strand Okazaki fragment RNA primers during DNA replication. Mediates the excision of single ribonucleotides from DNA:RNA duplexes. 
About this Structure
- Bubeck D, Reijns MA, Graham SC, Astell KR, Jones EY, Jackson AP. PCNA directs type 2 RNase H activity on DNA replication and repair substrates. Nucleic Acids Res. 2011 Jan 17. PMID:21245041 doi:10.1093/nar/gkq980
- ↑ Burkovics P, Hajdu I, Szukacsov V, Unk I, Haracska L. Role of PCNA-dependent stimulation of 3'-phosphodiesterase and 3'-5' exonuclease activities of human Ape2 in repair of oxidative DNA damage. Nucleic Acids Res. 2009 Jul;37(13):4247-55. doi: 10.1093/nar/gkp357. Epub 2009, May 13. PMID:19443450 doi:10.1093/nar/gkp357
- ↑ Motegi A, Liaw HJ, Lee KY, Roest HP, Maas A, Wu X, Moinova H, Markowitz SD, Ding H, Hoeijmakers JH, Myung K. Polyubiquitination of proliferating cell nuclear antigen by HLTF and SHPRH prevents genomic instability from stalled replication forks. Proc Natl Acad Sci U S A. 2008 Aug 26;105(34):12411-6. Epub 2008 Aug 21. PMID:18719106 doi:0805685105
- ↑ Figiel M, Chon H, Cerritelli SM, Cybulska M, Crouch RJ, Nowotny M. The structural and biochemical characterization of human RNase H2 complex reveals the molecular basis for substrate recognition and Aicardi-Goutieres syndrome defects. J Biol Chem. 2011 Mar 25;286(12):10540-50. Epub 2010 Dec 22. PMID:21177858 doi:10.1074/jbc.M110.181974
- ↑ Crow YJ, Leitch A, Hayward BE, Garner A, Parmar R, Griffith E, Ali M, Semple C, Aicardi J, Babul-Hirji R, Baumann C, Baxter P, Bertini E, Chandler KE, Chitayat D, Cau D, Dery C, Fazzi E, Goizet C, King MD, Klepper J, Lacombe D, Lanzi G, Lyall H, Martinez-Frias ML, Mathieu M, McKeown C, Monier A, Oade Y, Quarrell OW, Rittey CD, Rogers RC, Sanchis A, Stephenson JB, Tacke U, Till M, Tolmie JL, Tomlin P, Voit T, Weschke B, Woods CG, Lebon P, Bonthron DT, Ponting CP, Jackson AP. Mutations in genes encoding ribonuclease H2 subunits cause Aicardi-Goutieres syndrome and mimic congenital viral brain infection. Nat Genet. 2006 Aug;38(8):910-6. Epub 2006 Jul 16. PMID:16845400 doi:http://dx.doi.org/10.1038/ng1842