Structural analysis of the catalytic domain of Artemis endonuclease/SNM1C reveals distinct structural features

Abstract

The endonuclease Artemis is responsible for opening DNA hairpins during V(D)J recombination and for processing a subset of pathological DNA double-strand breaks. Artemis is an attractive target for the development of therapeutics to manage various B cell and T cell tumors, because failure to open DNA hairpins and accumulation of chromosomal breaks may reduce the proliferation and viability of pre-T and pre-B cell derivatives. However, structure-based drug discovery of specific Artemis inhibitors has been hampered by a lack of crystal structures. Here, we report the structure of the catalytic domain of recombinant human Artemis. The catalytic domain displayed a polypeptide fold similar overall to those of other members in the DNA cross-link repair gene SNM1 family and in mRNA 3′-end-processing endonuclease CPSF-73, containing metallo-β-lactamase and β-CASP domains and a cluster of conserved histidine and aspartate residues capable of binding two metal atoms in the catalytic site. As in SNM1A, only one zinc ion was located in the Artemis active site. However, Artemis displayed several unique features. Unlike in other members of this enzyme class, a second zinc ion was present in the β-CASP domain that leads to structural reorientation of the putative DNA-binding surface and extends the substrate-binding pocket to a new pocket, pocket III. Moreover, the substrate-binding surface exhibited a dominant and extensive positive charge distribution compared with that in the structures of SNM1A and SNM1B, presumably because of the structurally distinct DNA substrate of Artemis. The structural features identified here may provide opportunities for designing selective Artemis inhibitors. The endonuclease Artemis is responsible for opening DNA hairpins during V(D)J recombination and for processing a subset of pathological DNA double-strand breaks. Artemis is an attractive target for the development of therapeutics to manage various B cell and T cell tumors, because failure to open DNA hairpins and accumulation of chromosomal breaks may reduce the proliferation and viability of pre-T and pre-B cell derivatives. However, structure-based drug discovery of specific Artemis inhibitors has been hampered by a lack of crystal structures. Here, we report the structure of the catalytic domain of recombinant human Artemis. The catalytic domain displayed a polypeptide fold similar overall to those of other members in the DNA cross-link repair gene SNM1 family and in mRNA 3′-end-processing endonuclease CPSF-73, containing metallo-β-lactamase and β-CASP domains and a cluster of conserved histidine and aspartate residues capable of binding two metal atoms in the catalytic site. As in SNM1A, only one zinc ion was located in the Artemis active site. However, Artemis displayed several unique features. Unlike in other members of this enzyme class, a second zinc ion was present in the β-CASP domain that leads to structural reorientation of the putative DNA-binding surface and extends the substrate-binding pocket to a new pocket, pocket III. Moreover, the substrate-binding surface exhibited a dominant and extensive positive charge distribution compared with that in the structures of SNM1A and SNM1B, presumably because of the structurally distinct DNA substrate of Artemis. The structural features identified here may provide opportunities for designing selective Artemis inhibitors. V(D)J recombination is the process by which T cells and B cells randomly assemble variable (V), diversity (D), and joining (J) gene segments to generate unique Igs and T cell receptors that can collectively recognize an almost infinite variety of different antigens (1Roth D.B. V(D)J recombination: mechanism, errors, and fidelity.Microbiol. Spectr. 2014; 2: 1010.1128/microbiolspec.MDNA3-0041-2014Google Scholar). Artemis endonuclease is essential for the completion of this process (Fig. 1). It forms a complex with the DNA-dependent protein kinase catalytic subunit (DNA-PKcs), which phosphorylates Artemis to reveal a structure-specific endonuclease activity that opens the DNA hairpins generated by the RAG (recombination activation gene) complex during the V(D)J recombination process (2Ma Y. Pannicke U. Schwarz K. Lieber M.R. Hairpin opening and overhang processing by an Artemis/DNA-dependent protein kinase complex in nonhomologous end joining and V(D)J recombination.Cell. 2002; 108: 781-79410.1016/S0092-8674(02)00671-2Abstract Full Text Full Text PDF PubMed Scopus (780) Google Scholar). Because the Artemis–DNA-PKcs complex is the only enzyme that is capable of opening DNA hairpins, loss-of-function mutants in either Artemis or DNA-PKcs block B and T cell maturation and increase the radiosensitivity of pre-B and pre-T cells. Humans and mice with loss-of-function Artemis gene mutations display severe combined immunodeficiency (SCID) (3Moshous D. Callebaut I. de Chasseval R. Corneo B. Cavazzana-Calvo M. Le Deist F. Tezcan I. Sanal O. Bertrand Y. Philippe N. Fischer A. de Villartay J.P. Artemis, a novel DNA double-strand break repair/V(D)J recombination protein, is mutated in human severe combined immune deficiency.Cell. 2001; 105: 177-18610.1016/S0092-8674(01)00309-9Abstract Full Text Full Text PDF PubMed Scopus (673) Google Scholar). Artemis-deficient mice and DNA-PKcs-deficient mice exhibit a similar SCID phenotype and accumulate hairpin coding ends in thymocytes, suggesting that the Artemis–DNA-PKcs complex is the only enzyme that is capable of opening DNA hairpins (4Rooney S. Sekiguchi J. Zhu C. Cheng H.L. Manis J. Whitlow S. DeVido J. Foy D. Chaudhuri J. Lombard D. Alt F.W. Leaky Scid phenotype associated with defective V(D)J coding end processing in Artemis-deficient mice.Mol. Cell. 2002; 10: 1379-139010.1016/S1097-2765(02)00755-4Abstract Full Text Full Text PDF PubMed Scopus (213) Google Scholar). Human Artemis, 692 residues in length, contains an N-terminal catalytic domain (∼370 residues) with nuclease activity and a C-terminal regulatory region for DNA-PKcs interaction. The C-terminal segment (aa 448–462) is suggested to have a self-inhibitory role by interacting with the Artemis N-terminal catalytic domain (5Niewolik D. Peter I. Butscher C. Schwarz K. Autoinhibition of the nuclease ARTEMIS is mediated by a physical interaction between its catalytic and C-terminal domains.J. Biol. Chem. 2017; 292 (28082683): 3351-336510.1074/jbc.M116.770461Abstract Full Text Full Text PDF PubMed Scopus (10) Google Scholar). Artemis is activated through phosphorylation at multiple sites in the C-terminal region by DNA-PKcs, ataxia-telangiectasia mutated (ATM) kinase, and ataxia telangiectasia Rad3-related (ATR) serine/threonine kinases (6Dominski Z. Nucleases of the metallo-beta-lactamase family and their role in DNA and RNA metabolism.Crit. Rev. Biochem. Mol. Biol. 2007; 42 (17453916): 67-9310.1080/10409230701279118Crossref PubMed Scopus (96) Google Scholar, 7Callebaut I. Moshous D. Mornon J.-P. de Villartay J.-P. Metallo-beta-lactamase fold within nucleic acids processing enzymes: the beta-CASP family.Nucleic Acids Res. 2002; 30 (12177301): 3592-360110.1093/nar/gkf470Crossref PubMed Google Scholar, 8Mandel C.R. Kaneko S. Zhang H. Gebauer D. Vethantham V. Manley J.L. Tong L. Polyadenylation factor CPSF-73 is the pre-mRNA 3'-end-processing endonuclease.Nature. 2006; 444 (17128255): 953-95610.1038/nature05363Crossref PubMed Scopus (281) Google Scholar). In the context of V(D)J recombination, Artemis is activated through phosphorylation by DNA-PKcs, which is itself activated when bound to ligands with double-strand DNA (dsDNA) ends. The dsDNA ends include hairpinned DNA ends, which arise after RAG cutting of DNA. Based on amino acid sequence analysis, the N-terminal Artemis catalytic domain has been classified in the β-CASP (CPSF, Artemis, SNM1, and Pso) family with a β-CASP domain fused to a conserved metallo-β-lactamase fold (Fig. 2B). Within this family, there are a number of RNA nucleases, such as CPSF-73, Bacillus ribonucleases RNAS J1 and J2, and three human DNA nucleases, SNM1A, SNM1B/Apollo, and Artemis/SNM1C, which make up the SNM1 family (6Dominski Z. Nucleases of the metallo-beta-lactamase family and their role in DNA and RNA metabolism.Crit. Rev. Biochem. Mol. Biol. 2007; 42 (17453916): 67-9310.1080/10409230701279118Crossref PubMed Scopus (96) Google Scholar, 7Callebaut I. Moshous D. Mornon J.-P. de Villartay J.-P. Metallo-beta-lactamase fold within nucleic acids processing enzymes: the beta-CASP family.Nucleic Acids Res. 2002; 30 (12177301): 3592-360110.1093/nar/gkf470Crossref PubMed Google Scholar). The catalytic center is located in the metallo-β-lactamase domain and harbors metal ions for catalysis, for example, two zinc ions in the crystal structure of CPSF-73 (Fig. 2C) (8Mandel C.R. Kaneko S. Zhang H. Gebauer D. Vethantham V. Manley J.L. Tong L. Polyadenylation factor CPSF-73 is the pre-mRNA 3'-end-processing endonuclease.Nature. 2006; 444 (17128255): 953-95610.1038/nature05363Crossref PubMed Scopus (281) Google Scholar). Some common sequence motifs in this domain have been summarized, such as motifs I–IV (9Aravind L. An evolutionary classification of the metallo-beta-lactamase fold proteins.In Silico Biol. 1999; 1 (11471246): 69-91PubMed Google Scholar) and motifs A–C. For Artemis, these motifs are the following: motif I, Asp-17; motif II, His-33, His-35, Asp-37, and His-38; motif III, His-115; motif IV, Asp-136; motif A, Asp-165; motif B, His-319; and motif C, V341 (Fig. 3) (7Callebaut I. Moshous D. Mornon J.-P. de Villartay J.-P. Metallo-beta-lactamase fold within nucleic acids processing enzymes: the beta-CASP family.Nucleic Acids Res. 2002; 30 (12177301): 3592-360110.1093/nar/gkf470Crossref PubMed Google Scholar). The structure of human CPSF-73 reveals that motifs II, III, IV, and C directly coordinate to the metal center; motifs A and B a and may as a acid for the during the catalytic (8Mandel C.R. Kaneko S. Zhang H. Gebauer D. Vethantham V. Manley J.L. Tong L. Polyadenylation factor CPSF-73 is the pre-mRNA 3'-end-processing endonuclease.Nature. 2006; 444 (17128255): 953-95610.1038/nature05363Crossref PubMed Scopus (281) Google Scholar). of motifs in Artemis have been for these sequence residues have been to and for the activity of Artemis U. Y. D. Lieber M.R. Schwarz K. and of the structure-specific nuclease J. PubMed Scopus Google Scholar). The β-CASP domain is in the metallo-β-lactamase It the substrate binding pocket within the metallo-β-lactamase and is to substrate of human SNM1 family The of SNM1 family members was with J. a for multiple protein sequence and structure Acids Res. PubMed Scopus Google by and displayed a for Biol. PubMed Scopus Google Scholar). The structure motifs by C. of protein of and PubMed Scopus Google Scholar) and in for the metallo-β-lactamase domain and for the β-CASP The are as as and as The conserved residues of SNM1 family are with for zinc and for of the second metal ion in the catalytic site. that coordinate zinc in the β-CASP domain are with these residues are conserved SNM1 family residues in Artemis on the substrate DNA binding the crystal structures of CPSF-73 (8Mandel C.R. Kaneko S. Zhang H. Gebauer D. Vethantham V. Manley J.L. Tong L. Polyadenylation factor CPSF-73 is the pre-mRNA 3'-end-processing endonuclease.Nature. 2006; 444 (17128255): 953-95610.1038/nature05363Crossref PubMed Scopus (281) Google SNM1A, and O. The structures of the SNM1A and nuclease domains reveal a for their distinct DNA processing Acids Res. PubMed Scopus Google Scholar) have been Artemis sequence to of these is to have a similar As the only endonuclease in this family, Artemis is to exhibit different structural to process double-strand DNA with various end structures Lieber M.R. the DNA of the at DNA Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, Lieber M.R. nuclease of Artemis and the DNA-PKcs Acids Res. PubMed Scopus Google Scholar). the complex is responsible for dsDNA this complex an attractive drug an of Artemis or DNA-PKcs with or with a to of the cells to the in Artemis are cells to (3Moshous D. Callebaut I. de Chasseval R. Corneo B. Cavazzana-Calvo M. Le Deist F. Tezcan I. Sanal O. Bertrand Y. Philippe N. Fischer A. de Villartay J.P. Artemis, a novel DNA double-strand break repair/V(D)J recombination protein, is mutated in human severe combined immune deficiency.Cell. 2001; 105: 177-18610.1016/S0092-8674(01)00309-9Abstract Full Text Full Text PDF PubMed Scopus (673) Google Scholar). of DNA-PKcs have in and have been F.W. D. C. M. M.R. B. M. A. discovery of a and selective DNA-dependent protein kinase Chem. PubMed Scopus (10) Google Scholar, A. C. DNA-dependent protein kinase for 2017; PubMed Scopus Google Scholar). of Artemis to of the that arise the of other Z. Lieber M.R. DNA-PKcs on the repair of V(D)J PubMed Scopus Google Scholar). As a of the serine/threonine protein kinase family, DNA-PKcs is in multiple such as nonhomologous end recombination, cell and as an target in PubMed Google as as V(D)J In Artemis has a unique catalytic DNA hairpin and in DNA recombination and nonhomologous end an Artemis structure is Here, we report the structure of the Artemis catalytic domain in two different crystal The catalytic domain of Artemis (aa was and cells. of the protein and with that the was and the second was other was is with that Artemis has multiple phosphorylation sites at its C-terminal region and in its catalytic domain Y. R. C. C. N. Artemis endonuclease J. 2006; PubMed Scopus Google Scholar, Y. Pannicke U. H. D. Schwarz K. Lieber M.R. The DNA-dependent protein kinase catalytic subunit phosphorylation sites in human Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, J. Z. S. Artemis is a phosphorylation target of and and is in the DNA Cell. Biol. PubMed Scopus Google Scholar). to Artemis of Artemis with a number of DNA was of crystal 1 when a overhang DNA was and the by was when a hairpin DNA was of forms that the different DNA with a present in the (Fig. However, after the structures the DNA the structures of either crystal which in a during Some was the of crystal 1 and a in crystal (Fig. The in crystal was in to the active identified by the metal that the DNA was present in the bound In crystal a of the metal center in the active site. However, the of the DNA with the surface of the protein, suggesting that to the protein in a and bound to with the of the in crystal the DNA was in the crystal Artemis the DNA with that the DNA the crystal during was a interaction. 1 one Artemis in the with the with two zinc two Artemis in the for residues residues and in the structures. The three of Artemis similar to with a in the of to (Fig. Because there was these three the Artemis structure in crystal 1 is here as the for and of structural features. Artemis exhibited the fold of the β-CASP family, with a metallo-β-lactamase domain and a β-CASP domain (Fig. 2B). of the β-CASP family, the β-CASP domain residues was the metallo-β-lactamase atoms of Artemis can to DNA SNM1A and with an of for (Fig. 2C) O. The structures of the SNM1A and nuclease domains reveal a for their distinct DNA processing Acids Res. PubMed Scopus Google Scholar). Artemis and RNA nuclease CPSF-73 an of when the metallo-β-lactamase and the β-CASP domains the was to for a of atoms the two that the between the two domains is conserved within the SNM1 family is different those of other RNA Artemis sequence with SNM1A or a structure-based (Fig. the three in the SNM1 family a within the metallo-β-lactamase The of structure motifs the of The structures of Artemis and CPSF-73 (aa and (aa these two are and in SNM1A and to SNM1A, SNM1B, Artemis has an (aa at the C the (aa and in different O. The structures of the SNM1A and nuclease domains reveal a for their distinct DNA processing Acids Res. PubMed Scopus Google Scholar). the N-terminal has a that forms an with The of Artemis (aa and SNM1A are located at the a SNM1A forms an In the β-CASP Artemis residues are a and (aa which is to (aa was present in or CPSF-73, in which this region the center of the SNM1A this region as in the Artemis structure residues of the residues in the SNM1A structure The region of Artemis is an structural which is in in the SNM1A and located on one of Artemis, suggesting that this is the putative substrate binding zinc ions located with (Fig. zinc ion is located at the active with by residues His-33, His-35, a and a (Fig. and to conserved motif and IV, and to motif II, with the sequence for the metallo-β-lactamase family (3Moshous D. Callebaut I. de Chasseval R. Corneo B. Cavazzana-Calvo M. Le Deist F. Tezcan I. Sanal O. Bertrand Y. Philippe N. Fischer A. de Villartay J.P. Artemis, a novel DNA double-strand break repair/V(D)J recombination protein, is mutated in human severe combined immune deficiency.Cell. 2001; 105: 177-18610.1016/S0092-8674(01)00309-9Abstract Full Text Full Text PDF PubMed Scopus (673) Google Scholar). residues are conserved in the SNM1 family, and one of in and in of Artemis U. Y. D. Lieber M.R. Schwarz K. and of the structure-specific nuclease J. PubMed Scopus Google Scholar). Artemis a second zinc ion in the active as with CPSF-73 (8Mandel C.R. Kaneko S. Zhang H. Gebauer D. Vethantham V. Manley J.L. Tong L. Polyadenylation factor CPSF-73 is the pre-mRNA 3'-end-processing endonuclease.Nature. 2006; 444 (17128255): 953-95610.1038/nature05363Crossref PubMed Scopus (281) Google Scholar). the residues and in motif are conserved and located at the as CPSF-73, the zinc in motif C of CPSF-73 was by in Artemis, and the was the active site. is conserved in the SNM1 a is a common for the The of this in SNM1A and are similar to that of was only one zinc ion located in the active of SNM1A, similar to Artemis. the to histidine in SNM1A activity and substrate B. M. J. K. O. of the human SNM1A and DNA repair Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). zinc ions in the was by in the B in Artemis with in CPSF-73 (Fig. which was to a acid to the in the (8Mandel C.R. Kaneko S. Zhang H. Gebauer D. Vethantham V. Manley J.L. Tong L. Polyadenylation factor CPSF-73 is the pre-mRNA 3'-end-processing endonuclease.Nature. 2006; 444 (17128255): 953-95610.1038/nature05363Crossref PubMed Scopus (281) Google Scholar). to forms a with the of residues to to endonuclease U. Y. D. Lieber M.R. Schwarz K. and of the structure-specific nuclease J. PubMed Scopus Google Scholar). The second zinc ion is located in the β-CASP to have a structural is unique to Artemis, as other β-CASP have a zinc binding within this zinc has by residues and (Fig. and are on two and which are located at similar in other members in the SNM1 Because of the of the between and is As an example, of its in SNM1A and The is located on an which is present in SNM1A, SNM1B, or The of this and the of a of its in SNM1A and (Fig. residues of this zinc binding motif conserved within the SNM1 However, are conserved in Artemis suggesting an for this structural is conserved within the SNM1 family and was to in metal ion at the active site. of the in and in of Artemis Villartay J.-P. N. Fischer A. Mornon J.-P. Lieber M.R. Callebaut I. A histidine in the beta-CASP domain of Artemis is for its in and in PubMed Scopus Google that this unique zinc binding motif in the β-CASP domain of Artemis is structurally and Because the metal ions the catalytic center for nucleases, the surface was to the active for DNA binding and zinc binding in the β-CASP domain and multiple within the active of Artemis exhibited a surface different those of SNM1A and (Fig. The catalytic zinc ion bound to pocket (Fig. which is located between the metallo-β-lactamase and β-CASP pocket is pocket by the of and pocket and in SNM1A and It has been that this region the of the DNA substrate for other SNM1 family members O. The structures of the SNM1A and nuclease domains reveal a for their distinct DNA processing Acids Res. PubMed Scopus Google Scholar). In Artemis, there was an pocket pocket I, which in the β-CASP domain by the reorientation of residues and residues by of residues to the zinc ion within the β-CASP The surface of Artemis exhibited a dominant positive charge residues and residues are conserved in Artemis and recognize DNA as the residues are unique to Artemis within the SNM1 family (Fig. As a SNM1A and as extensive as Artemis (Fig. have the structure of Artemis endonuclease with two different DNA a overhang and a DNA that Artemis an overall fold similar to that of other members of the SNM1 family and CPSF-73 unique such as a novel zinc binding in the β-CASP domain and a distinct substrate binding DNA in the SNM1 family, SNM1A, SNM1B/Apollo, and Artemis/SNM1C, exhibit a open substrate binding pocket and compared with RNA nuclease It is that this DNA to this Artemis extends its substrate binding to pocket III, which to and those of SNM1A and In residues are on this Artemis is the only endonuclease in the SNM1 family, because SNM1A and are to exhibit only Artemis is to process several different DNA substrate such as ends, hairpin ends, and DNA structures Lieber M.R. nuclease of Artemis and the DNA-PKcs Acids Res. PubMed Scopus Google Scholar). that Artemis has an substrate pocket to and fold the DNA ends. structure that pocket such a The novel zinc binding in the β-CASP domain in to and III. Moreover, of the zinc ion by and to structural in Artemis, to the of and III. For zinc by and in the of residues between these two residues compared with SNM1A and SNM1B, (Fig. The of directly pocket II, and is located at the of pocket (Fig. of Artemis activity in and mutations of in severe combined immune in Villartay J.-P. N. Fischer A. Mornon J.-P. Lieber M.R. Callebaut I. A histidine in the beta-CASP domain of Artemis is for its in and in PubMed Scopus Google suggesting that the structure by zinc binding at the novel zinc binding is for the activity and substrate of Artemis. we this an Artemis structure was and by the crystal of is different of those that we report the overall structures of the Artemis protein of the structures of residues in with an of (Fig. this the structural we for Artemis compared with those of other SNM1 family the between the metallo-β-lactamase and the β-CASP domains the of this structure was was residues which in two zinc binding motifs in the β-CASP domain and to the structure through interaction with a surface of The of was for the structures crystal The of in structures because of the the crystal the in a zinc and one ion located at the active in the metallo-β-lactamase domain in A ion the zinc ion in the active of structure and ligands with ligands residues His-33, His-35, and and the other two ligands a and an A second metal ion present on which was present in was a zinc ion to ligands with a ligands protein residues Asp-37, and and the other two ligands The center in was similar to that of CPSF-73, in which there are ligands the in CPSF-73 in motif C is by in Artemis. to the binding for the second metal ion in However, we that a such as or this with to coordinate with the metal ion that Artemis was one metal binding the center may during catalytic presumably by the DNA to the catalytic of nucleases, three on metal ion or two metal ions for diversity of and Rev. PubMed Scopus Google Scholar). in motif of Artemis the endonuclease in the motif activity of Artemis in an in U. Y. D. Lieber M.R. Schwarz K. and of the structure-specific nuclease J. PubMed Scopus Google Scholar). with the crystal this that the binding of a second metal ion is during catalysis, a binding was a center is for catalysis, may of Artemis was active in a was in containing zinc or (2Ma Y. Pannicke U. Schwarz K. Lieber M.R. Hairpin opening and overhang processing by an Artemis/DNA-dependent protein kinase complex in nonhomologous end joining and V(D)J recombination.Cell. 2002; 108: 781-79410.1016/S0092-8674(02)00671-2Abstract Full Text Full Text PDF PubMed Scopus (780) Google Scholar, S. D. Schwarz K. Lieber M.R. that the DNA endonuclease ARTEMIS has Biol. Chem. 2014; Full Text Full Text PDF PubMed Scopus Google Scholar). of M. in cells by of the A. PubMed Scopus Google Scholar, M. of in a cell a PubMed Scopus Google Scholar) are with the role for as the second metal ion during at the catalytic of Artemis. As Artemis is a drug these structures provide for in As the metal ions in the active are for nuclease to coordinate with a metal ion and at pocket may provide an for the development of a Artemis structures the surface and structural features of and of Artemis are unique in the SNM1 family, a distinct surface and charge for interaction. with the open pocket I, and may provide opportunities for and Human Artemis (aa was a in cells. The containing Artemis (aa with a C-terminal and a was a A C-terminal was to the sequence to provide a cells for at The cells by at in and containing and and by a at for The was at at for an and the was with at a of of cells. at for an the in an with of and and the protein was with and containing Artemis and with at a of and and at The protein was a and to a in The containing Artemis and the was to with The Artemis was a and with a of in Artemis at and was to and at was with at an of a was of with a was with the the The and of Artemis with was by the of the protein, 1 of was by an by to a at a of at with three Artemis was with and the was by with a to a on a and a at with The was in with the at and for and The ions for Artemis protein with the was the at generate of crystal the protein at 1 was with overhang DNA and at a of The was to Artemis a by 1 and 1 containing The with Artemis after The to by a for was in a similar hairpin DNA with a of The For crystal the to the with for and in for at the or at the at a of crystal 1 at the zinc and the to The of crystal to The with in Biol. PubMed Scopus Google Biol. PubMed Scopus Google M. L. M. and of a new Biol. PubMed Scopus Google and are and is the Biol. PubMed Scopus Google Scholar). The the by and was The structures for crystal forms by the structure as the by 2007; PubMed Scopus Google and the structures F. for the of crystal Biol. PubMed Scopus Google Scholar). The generated by S. the Biol. PubMed Scopus Google Scholar). The are in and cell a of of unique in are for the and and of protein of zinc of The in are for the For and in a new and the structural of Artemis have been in the and other are within the A. and for of the the of and of the at the was by the of the through a with has been in or in with the of and of of the a of of for the of by with DNA-dependent protein kinase catalytic subunit recombination activation gene at

Topics & Concepts