1
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Yuan H, Wang Y, Liu XP. The thumb subdomain of Pyrococcus furiosus DNA polymerase is responsible for deoxyuracil binding, hydrolysis and polymerization of nucleotides. Int J Biochem Cell Biol 2022; 144:106171. [PMID: 35093572 DOI: 10.1016/j.biocel.2022.106171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 01/02/2022] [Accepted: 01/24/2022] [Indexed: 11/26/2022]
Abstract
B-family DNA polymerases, which are found in eukaryotes, archaea, viruses, and some bacteria, participate in DNA replication and repair. Starting from the N-terminus of archaeal and bacterial B-family DNA polymerases, three domains include the N-terminal, exonuclease, and polymerase domains. The N-terminal domain of the archaeal B-family DNA polymerase has a conserved deoxyuracil-binding pocket for specially binding the deoxyuracil base on DNA. The exonuclease domain is responsible for removing the mismatched base pair. The polymerase domain is the core functional domain and takes a highly conserved structure composed of fingers, palm and thumb subdomains. Previous studies have demonstrated that the thumb subdomain mainly functions as a DNA-binding element and has coordination with the exonuclease domain and palm subdomain. To further elucidate the possible functions of the thumb subdomain of archaeal B-family DNA polymerases, the thumb subdomain of Pyrococcus furiosus DNA polymerase was mutated, and the effects on three activities were characterized. Our results demonstrate that the thumb subdomain participates in the three activities of archaeal B-family DNA polymerases as a common structural element. Both the N-terminal deoxyuracil-binding pocket and thumb subdomain are critical for deoxyuracil binding. Moreover, the thumb subdomain assists DNA polymerization and hydrolysis reactions, but it does not contribute to the fidelity of DNA polymerization.
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Affiliation(s)
- Hui Yuan
- Department of Thoracic Surgery, Fudan University Shanghai Cancer Center, Shanghai, China; Cancer Institute, Fudan University Shanghai Cancer Center, Shanghai, China
| | - You Wang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dong-Chuan Road, Shanghai 200240, China
| | - Xi-Peng Liu
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dong-Chuan Road, Shanghai 200240, China; Joint International Research Laboratory of Metabolic & Developmental Sciences (Ministry of Education), Shanghai Jiao Tong University, 800 Dong-Chuan Road, Shanghai 200240, China.
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2
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Engineered viral DNA polymerase with enhanced DNA amplification capacity: a proof-of-concept of isothermal amplification of damaged DNA. Sci Rep 2020; 10:15046. [PMID: 32929102 PMCID: PMC7490695 DOI: 10.1038/s41598-020-71773-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 08/20/2020] [Indexed: 11/24/2022] Open
Abstract
The development of whole genome amplification (WGA) and related methods, coupled with the dramatic growth of sequencing capacities, has changed the paradigm of genomic and genetic analyses. This has led to a continual requirement of improved DNA amplification protocols and the elaboration of new tailored methods. As key elements in WGA, identification and engineering of novel, faithful and processive DNA polymerases is a driving force in the field. We have engineered the B-family DNA polymerase of virus Bam35 with a C-terminal fusion of DNA-binding motifs. The new protein, named B35-HhH, shows faithful DNA replication in the presence of magnesium or an optimised combination of magnesium and manganese divalent cofactors, which enhances the replication of damaged DNA substrates. Overall, the newly generated variant displays improved amplification performance, sensitivity, translesion synthesis and resistance to salt, which are of great interest for several applications of isothermal DNA amplification. Further, rolling-circle amplification of abasic site-containing minicircles provides a proof-of-concept for using B35-HhH for processive amplification of damaged DNA samples.
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3
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Sakatani Y, Mizuuchi R, Ichihashi N. In vitro evolution of phi29 DNA polymerases through compartmentalized gene expression and rolling-circle replication. Protein Eng Des Sel 2020; 32:481-487. [PMID: 32533140 DOI: 10.1093/protein/gzaa011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Revised: 03/20/2020] [Accepted: 04/29/2020] [Indexed: 12/20/2022] Open
Abstract
Phi29 DNA polymerase is widely used for DNA amplification through rolling-circle replication or multiple displacement amplification. Here, we performed completely in vitro artificial evolution of phi29 DNA polymerase by combining the in vitro compartmentalization and the gene expression-coupled rolling-circle replication of a circular DNA encoding the polymerase. We conducted the experiments in six different conditions composed of three different levels of inhibitor concentrations with two different DNA labeling methods. One of the experiments was performed in our previous study and the other five experiments were newly conducted in this study. Under all conditions, we found several mutations that enhance the rolling-circle amplification by the polymerase when it was expressed in the reconstituted gene expression system. Especially, a combinatorial mutant polymerase (K555T/D570N) exhibits significantly higher rolling-circle activity than the wild type. These highly active mutant polymerases would be useful for various applications.
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Affiliation(s)
- Yoshihiro Sakatani
- Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, 1-5 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Ryo Mizuuchi
- Komaba Institute for Science, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo 153-8902, Japan.,JST, PRESTO, Kawaguchi, Saitama 332-0012, Japan
| | - Norikazu Ichihashi
- Komaba Institute for Science, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo 153-8902, Japan.,Department of Life Science, Graduate School of Arts and Science, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan.,Universal Biology Institute, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan
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4
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Del Prado A, Rodríguez I, Lázaro JM, Moreno-Morcillo M, de Vega M, Salas M. New insights into the coordination between the polymerization and 3'-5' exonuclease activities in ϕ29 DNA polymerase. Sci Rep 2019; 9:923. [PMID: 30696917 PMCID: PMC6351526 DOI: 10.1038/s41598-018-37513-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 12/06/2018] [Indexed: 11/09/2022] Open
Abstract
Bacteriophage ϕ29 DNA polymerase has two activities: DNA polymerization and 3′-5′ exonucleolysis governed by catalytic sites present in two structurally distant domains. These domains must work together to allow the correct replication of the template and to prevent the accumulation of errors in the newly synthesized DNA strand. ϕ29 DNA polymerase is endowed with a high processivity and strand displacement capacity together with a high fidelity. Previous studies of its crystallographic structure suggested possible interactions of residues of the exonuclease domain like the Gln180 with the fingers subdomain, or water mediated and direct hydrogen bond by the polar groups of residues Tyr101 and Thr189 that could stabilize DNA binding. To analyse their functional importance for the exonuclease activity of ϕ29 DNA polymerase we engineered mutations to encode amino acid substitutions. Our results confirm that both residues, Tyr101 and Thr189 are involved in the 3′-5′ exonuclease activity and in binding the dsDNA. In addition, Tyr101 is playing a role in processivity and Thr189 is an important determinant in the fidelity of the DNA polymerase. On the other hand, the biochemical characterization of the mutant derivatives of residue Gln180 showed how the mutations introduced enhanced the 3′-5′ exonuclease activity of the enzyme. A potential structural conformation prone to degrade the substrate is discussed.
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Affiliation(s)
- Alicia Del Prado
- Centro de Biología Molecular "Severo Ochoa," (Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid), Universidad Autónoma, Cantoblanco, 28049, Madrid, Spain
| | - Irene Rodríguez
- Centro de Biología Molecular "Severo Ochoa," (Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid), Universidad Autónoma, Cantoblanco, 28049, Madrid, Spain
| | - José María Lázaro
- Centro de Biología Molecular "Severo Ochoa," (Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid), Universidad Autónoma, Cantoblanco, 28049, Madrid, Spain
| | - María Moreno-Morcillo
- Centro de Biología Molecular "Severo Ochoa," (Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid), Universidad Autónoma, Cantoblanco, 28049, Madrid, Spain
| | - Miguel de Vega
- Centro de Biología Molecular "Severo Ochoa," (Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid), Universidad Autónoma, Cantoblanco, 28049, Madrid, Spain
| | - Margarita Salas
- Centro de Biología Molecular "Severo Ochoa," (Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid), Universidad Autónoma, Cantoblanco, 28049, Madrid, Spain.
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5
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Salas M, Holguera I, Redrejo-Rodríguez M, de Vega M. DNA-Binding Proteins Essential for Protein-Primed Bacteriophage Φ29 DNA Replication. Front Mol Biosci 2016; 3:37. [PMID: 27547754 PMCID: PMC4974454 DOI: 10.3389/fmolb.2016.00037] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 07/20/2016] [Indexed: 01/25/2023] Open
Abstract
Bacillus subtilis phage Φ29 has a linear, double-stranded DNA 19 kb long with an inverted terminal repeat of 6 nucleotides and a protein covalently linked to the 5′ ends of the DNA. This protein, called terminal protein (TP), is the primer for the initiation of replication, a reaction catalyzed by the viral DNA polymerase at the two DNA ends. The DNA polymerase further elongates the nascent DNA chain in a processive manner, coupling strand displacement with elongation. The viral protein p5 is a single-stranded DNA binding protein (SSB) that binds to the single strands generated by strand displacement during the elongation process. Viral protein p6 is a double-stranded DNA binding protein (DBP) that preferentially binds to the origins of replication at the Φ29 DNA ends and is required for the initiation of replication. Both SSB and DBP are essential for Φ29 DNA amplification. This review focuses on the role of these phage DNA-binding proteins in Φ29 DNA replication both in vitro and in vivo, as well as on the implication of several B. subtilis DNA-binding proteins in different processes of the viral cycle. We will revise the enzymatic activities of the Φ29 DNA polymerase: TP-deoxynucleotidylation, processive DNA polymerization coupled to strand displacement, 3′–5′ exonucleolysis and pyrophosphorolysis. The resolution of the Φ29 DNA polymerase structure has shed light on the translocation mechanism and the determinants responsible for processivity and strand displacement. These two properties have made Φ29 DNA polymerase one of the main enzymes used in the current DNA amplification technologies. The determination of the structure of Φ29 TP revealed the existence of three domains: the priming domain, where the primer residue Ser232, as well as Phe230, involved in the determination of the initiating nucleotide, are located, the intermediate domain, involved in DNA polymerase binding, and the N-terminal domain, responsible for DNA binding and localization of the TP at the bacterial nucleoid, where viral DNA replication takes place. The biochemical properties of the Φ29 DBP and SSB and their function in the initiation and elongation of Φ29 DNA replication, respectively, will be described.
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Affiliation(s)
- Margarita Salas
- Centro de Biología Molecular Severo Ochoa (Consejo Superior de Investigaciones Científicas), Universidad Autónoma de Madrid Madrid, Spain
| | - Isabel Holguera
- Centro de Biología Molecular Severo Ochoa (Consejo Superior de Investigaciones Científicas), Universidad Autónoma de Madrid Madrid, Spain
| | - Modesto Redrejo-Rodríguez
- Centro de Biología Molecular Severo Ochoa (Consejo Superior de Investigaciones Científicas), Universidad Autónoma de Madrid Madrid, Spain
| | - Miguel de Vega
- Centro de Biología Molecular Severo Ochoa (Consejo Superior de Investigaciones Científicas), Universidad Autónoma de Madrid Madrid, Spain
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6
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Abstract
The requirement of DNA polymerases for a 3'-hydroxyl (3'-OH) group to prime DNA synthesis raised the question about how the ends of linear chromosomes could be replicated. Among the strategies that have evolved to handle the end replication problem, a group of linear phages and eukaryotic and archaeal viruses, among others, make use of a protein (terminal protein, TP) that primes DNA synthesis from the end of their genomes. The replicative DNA polymerase recognizes the OH group of a specific residue in the TP to initiate replication that is guided by an internal 3' nucleotide of the template strand. By a sliding-back mechanism or variants of it the terminal nucleotide(s) is(are) recovered and the TP becomes covalently attached to the genome ends. Bacillus subtilis phage ϕ29 is the organism in which such a mechanism has been studied more extensively, having allowed to lay the foundations of the so-called protein-primed replication mechanism. Here we focus on the main biochemical and structural features of the two main proteins responsible for the protein-primed initiation step: the DNA polymerase and the TP. Thus, we will discuss the structural determinants of the DNA polymerase responsible for its ability to use sequentially a TP and a DNA as primers, as well as for its inherent capacity to couple high processive synthesis to strand displacement. On the other hand, we will review how TP primes initiation followed by a transition step for further DNA-primed replication by the same polymerase molecule. Finally, we will review how replication is compartmentalized in vivo.
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Affiliation(s)
- M Salas
- Instituto de Biología Molecular "Eladio Viñuela" (CSIC), Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, Cantoblanco, Madrid, Spain.
| | - M de Vega
- Instituto de Biología Molecular "Eladio Viñuela" (CSIC), Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, Cantoblanco, Madrid, Spain.
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7
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Berjón-Otero M, Villar L, de Vega M, Salas M, Redrejo-Rodríguez M. DNA polymerase from temperate phage Bam35 is endowed with processive polymerization and abasic sites translesion synthesis capacity. Proc Natl Acad Sci U S A 2015; 112:E3476-84. [PMID: 26100910 PMCID: PMC4500267 DOI: 10.1073/pnas.1510280112] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
DNA polymerases (DNAPs) responsible for genome replication are highly faithful enzymes that nonetheless cannot deal with damaged DNA. In contrast, translesion synthesis (TLS) DNAPs are suitable for replicating modified template bases, although resulting in very low-fidelity products. Here we report the biochemical characterization of the temperate bacteriophage Bam35 DNA polymerase (B35DNAP), which belongs to the protein-primed subgroup of family B DNAPs, along with phage Φ29 and other viral and mobile element polymerases. B35DNAP is a highly faithful DNAP that can couple strand displacement to processive DNA synthesis. These properties allow it to perform multiple displacement amplification of plasmid DNA with a very low error rate. Despite its fidelity and proofreading activity, B35DNAP was able to successfully perform abasic site TLS without template realignment and inserting preferably an A opposite the abasic site (A rule). Moreover, deletion of the TPR2 subdomain, required for processivity, impaired primer extension beyond the abasic site. Taken together, these findings suggest that B35DNAP may perform faithful and processive genome replication in vivo and, when required, TLS of abasic sites.
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Affiliation(s)
- Mónica Berjón-Otero
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
| | - Laurentino Villar
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
| | - Miguel de Vega
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
| | - Margarita Salas
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
| | - Modesto Redrejo-Rodríguez
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
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8
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Ganai RA, Bylund GO, Johansson E. Switching between polymerase and exonuclease sites in DNA polymerase ε. Nucleic Acids Res 2014; 43:932-42. [PMID: 25550436 PMCID: PMC4333401 DOI: 10.1093/nar/gku1353] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The balance between exonuclease and polymerase activities promotes DNA synthesis over degradation when nucleotides are correctly added to the new strand by replicative B-family polymerases. Misincorporations shift the balance toward the exonuclease site, and the balance tips back in favor of DNA synthesis when the incorrect nucleotides have been removed. Most B-family DNA polymerases have an extended β-hairpin loop that appears to be important for switching from the exonuclease site to the polymerase site, a process that affects fidelity of the DNA polymerase. Here, we show that DNA polymerase ε can switch between the polymerase site and exonuclease site in a processive manner despite the absence of an extended β-hairpin loop. K967 and R988 are two conserved amino acids in the palm and thumb domain that interact with bases on the primer strand in the minor groove at positions n−2 and n−4/n−5, respectively. DNA polymerase ε depends on both K967 and R988 to stabilize the 3′-terminus of the DNA within the polymerase site and on R988 to processively switch between the exonuclease and polymerase sites. Based on a structural alignment with DNA polymerase δ, we propose that arginines corresponding to R988 might have a similar function in other B-family polymerases.
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Affiliation(s)
- Rais A Ganai
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-90187 Umeå, Sweden
| | - Göran O Bylund
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-90187 Umeå, Sweden
| | - Erik Johansson
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-90187 Umeå, Sweden
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9
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del Prado A, Lázaro JM, Villar L, Salas M, de Vega M. Dual role of φ29 DNA polymerase Lys529 in stabilisation of the DNA priming-terminus and the terminal protein-priming residue at the polymerisation site. PLoS One 2013; 8:e72765. [PMID: 24023769 PMCID: PMC3762793 DOI: 10.1371/journal.pone.0072765] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 07/12/2013] [Indexed: 11/18/2022] Open
Abstract
Resolution of the crystallographic structure of φ29 DNA polymerase binary and ternary complexes showed that residue Lys529, located at the C-terminus of the palm subdomain, establishes contacts with the 3' terminal phosphodiester bond. In this paper, site-directed mutants at this Lys residue were used to analyse its functional importance for the synthetic activities of φ29 DNA polymerase, an enzyme that starts linear φ29 DNA replication using a terminal protein (TP) as primer. Our results show that single replacement of φ29 DNA polymerase residue Lys529 by Ala or Glu decreases the stabilisation of the primer-terminus at the polymerisation active site, impairing both the insertion of the incoming nucleotide when DNA and TP are used as primers and the translocation step required for the next incoming nucleotide incorporation. In addition, combination of the DNA polymerase mutants with a TP derivative at residue Glu233, neighbour to the priming residue Ser232, leads us to infer a direct contact between Lys529 and Glu233 for initiation of TP-DNA replication. Altogether, the results are compatible with a sequential binding of φ29 DNA polymerase residue Lys529 with TP and DNA during replication of TP-DNA.
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Affiliation(s)
- Alicia del Prado
- Instituto de Biología Molecular “Eladio Viñuela” (CSIC), Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), Universidad Autónoma, Cantoblanco, Madrid, Spain
| | - José M. Lázaro
- Instituto de Biología Molecular “Eladio Viñuela” (CSIC), Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), Universidad Autónoma, Cantoblanco, Madrid, Spain
| | - Laurentino Villar
- Instituto de Biología Molecular “Eladio Viñuela” (CSIC), Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), Universidad Autónoma, Cantoblanco, Madrid, Spain
| | - Margarita Salas
- Instituto de Biología Molecular “Eladio Viñuela” (CSIC), Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), Universidad Autónoma, Cantoblanco, Madrid, Spain
- * E-mail:
| | - Miguel de Vega
- Instituto de Biología Molecular “Eladio Viñuela” (CSIC), Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), Universidad Autónoma, Cantoblanco, Madrid, Spain
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10
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Viikov K, Jasnovidova O, Tamm T, Sedman J. C-terminal extension of the yeast mitochondrial DNA polymerase determines the balance between synthesis and degradation. PLoS One 2012; 7:e33482. [PMID: 22432028 PMCID: PMC3303844 DOI: 10.1371/journal.pone.0033482] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Accepted: 02/15/2012] [Indexed: 11/18/2022] Open
Abstract
Saccharomyces cerevisiae mitochondrial DNA polymerase (Mip1) contains a C-terminal extension (CTE) of 279 amino acid residues. The CTE is required for mitochondrial DNA maintenance in yeast but is absent in higher eukaryotes. Here we use recombinant Mip1 C-terminal deletion mutants to investigate functional importance of the CTE. We show that partial removal of the CTE in Mip1Δ216 results in strong preference for exonucleolytic degradation rather than DNA polymerization. This disbalance in exonuclease and polymerase activities is prominent at suboptimal dNTP concentrations and in the absence of correctly pairing nucleotide. Mip1Δ216 also displays reduced ability to synthesize DNA through double-stranded regions. Full removal of the CTE in Mip1Δ279 results in complete loss of Mip1 polymerase activity, however the mutant retains its exonuclease activity. These results allow us to propose that CTE functions as a part of Mip1 polymerase domain that stabilizes the substrate primer end at the polymerase active site, and is therefore required for efficient mitochondrial DNA replication in vivo.
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Affiliation(s)
| | | | | | - Juhan Sedman
- Department of Biochemistry, Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
- * E-mail:
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11
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Szczepanowska K, Foury F. A cluster of pathogenic mutations in the 3'-5' exonuclease domain of DNA polymerase gamma defines a novel module coupling DNA synthesis and degradation. Hum Mol Genet 2010; 19:3516-29. [PMID: 20601675 DOI: 10.1093/hmg/ddq267] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Mutations in DNA polymerase gamma (pol g), the unique replicase inside mitochondria, cause a broad and complex spectrum of diseases in human. We have used Mip1, the yeast pol g, as a model enzyme to characterize six pathogenic pol g mutations. Four mutations clustered in a highly conserved 3'-5' exonuclease module are localized in the DNA-binding channel in close vicinity to the polymerase domain. They result in an increased frequency of point mutations and high instability of the mitochondrial DNA (mtDNA) in yeast cells, and unexpectedly for mutator mutations in the exonuclease domain, they favour exonucleolysis versus polymerization. This trait is associated with highly decreased DNA-binding affinity and poorly processive DNA synthesis. Our data show for the first time that a 3'-5' exonuclease module of pol g plays a crucial role in the coordination of the polymerase and exonuclease functions and they strongly suggest that in patients the disease is not caused by defective proofreading but results from poor mtDNA replication generated by a severe imbalance between DNA synthesis and degradation.
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Affiliation(s)
- Karolina Szczepanowska
- Institute of Life Sciences, Croix du Sud 4/15, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
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12
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Aller P, Ye Y, Wallace SS, Burrows CJ, Doublié S. Crystal structure of a replicative DNA polymerase bound to the oxidized guanine lesion guanidinohydantoin. Biochemistry 2010; 49:2502-9. [PMID: 20166752 DOI: 10.1021/bi902195p] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The oxidation of guanine generates one of the most common DNA lesions, 8-oxo-7,8-dihydroguanine (8-oxoG). The further oxidation of 8-oxoG can produce either guanidinohydantoin (Gh) in duplex DNA or spiroiminodihydantoin (Sp) in nucleosides and ssDNA. Although Gh can be a strong block for replicative DNA polymerases such as RB69 DNA polymerase, this lesion is also mutagenic: DNA polymerases bypass Gh by preferentially incorporating a purine with a slight preference for adenine, which results in G.C --> T.A or G.C --> C.G transversions. The 2.15 A crystal structure of the replicative RB69 DNA polymerase in complex with DNA containing Gh reveals that Gh is extrahelical and rotated toward the major groove. In this conformation Gh is no longer in position to serve as a templating base for the incorporation of an incoming nucleotide. This work also constitutes the first crystallographic structure of Gh, which is stabilized in the R configuration in the two polymerase/DNA complexes present in the crystal asymmetric unit. In contrast to 8-oxoG, Gh is found in a high syn conformation in the DNA duplex and therefore presents the same hydrogen bond donor and acceptor pattern as thymine, which explains the propensity of DNA polymerases to incorporate a purine opposite Gh when bypass occurs.
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Affiliation(s)
- Pierre Aller
- Department of Microbiology and Molecular Genetics, Stafford Hall, University of Vermont, Burlington, Vermont 05405, USA
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13
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Pérez-Arnaiz P, Lázaro JM, Salas M, de Vega M. Functional importance of bacteriophage phi29 DNA polymerase residue Tyr148 in primer-terminus stabilisation at the 3'-5' exonuclease active site. J Mol Biol 2009; 391:797-807. [PMID: 19576228 DOI: 10.1016/j.jmb.2009.06.068] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Revised: 06/23/2009] [Accepted: 06/25/2009] [Indexed: 11/17/2022]
Abstract
Recent crystallographic resolution of varphi29 DNA polymerase complexes with ssDNA at its 3'-5' exonuclease active site has allowed the identification of residues Pro129 and Tyr148 as putative ssDNA ligands, the latter being conserved in the Kx(2)h motif of proofreading family B DNA polymerases. Single substitution of varphi29 DNA polymerase residue Tyr148 to Ala rendered an enzyme with a reduced capacity to stabilize the binding of the primer terminus at the 3'-5' exonuclease active site, not having a direct role in the catalysis of the reaction. Analysis of the 3'-5' exonuclease on primer/template structures showed a critical role for residue Tyr148 in the proofreading of DNA polymerisation errors. In addition, Tyr148 is not involved in coupling polymerisation to strand displacement in contrast to the catalytic residues responsible for the exonuclease reaction, its role being restricted to stabilisation of the frayed 3' terminus at the exonuclease active site. Altogether, the results lead us to extend the consensus sequence of the above motif of proofreading family B DNA polymerases into Kx(2)hxA. The different solutions adopted by proofreading DNA polymerases to stack the 3' terminus at the exonuclease site are discussed. In addition, the results obtained with mutants at varphi29 DNA polymerase residue Pro129 allow us to rule out a functional role as ssDNA ligand for this residue.
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Affiliation(s)
- Patricia Pérez-Arnaiz
- Instituto de Biología Molecular "Eladio Viñuela", Centro de Biología Molecular "Severo Ochoa", Cantoblanco, Madrid, Spain
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14
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Rodríguez I, Lázaro JM, Salas M, de Vega M. Involvement of the TPR2 subdomain movement in the activities of phi29 DNA polymerase. Nucleic Acids Res 2008; 37:193-203. [PMID: 19033368 PMCID: PMC2615600 DOI: 10.1093/nar/gkn928] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The polymerization domain of phi29 DNA polymerase acquires a toroidal shape by means of an arch-like structure formed by the specific insertion TPR2 (Terminal Protein Region 2) and the thumb subdomain. TPR2 is connected to the fingers and palm subdomains through flexible regions, suggesting that it can undergo conformational changes. To examine whether such changes take place, we have constructed a phi29 DNA polymerase mutant able to form a disulfide bond between the apexes of TPR2 and thumb to limit the mobility of TPR2. Biochemical analysis of the mutant led us to conclude that TPR2 moves away from the thumb to allow the DNA polymerase to replicate circular ssDNA. Despite the fact that no TPR2 motion is needed to allow the polymerase to use the terminal protein (TP) as primer during the initiation of phi29 TP-DNA replication, the disulfide bond prevents the DNA polymerase from entering the elongation phase, suggesting that TPR2 movements are necessary to allow the TP priming domain to move out from the polymerase during transition from initiation to elongation. Furthermore, the TPR2-thumb bond does not affect the equilibrium between the polymerization and exonuclease activities, leading us to propose a primer-terminus transference model between both active sites.
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Affiliation(s)
- Irene Rodríguez
- Instituto de Biología Molecular Eladio Viñuela (CSIC), Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Cantoblanco, Madrid, Spain
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15
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Hogg M, Aller P, Konigsberg W, Wallace SS, Doublié S. Structural and biochemical investigation of the role in proofreading of a beta hairpin loop found in the exonuclease domain of a replicative DNA polymerase of the B family. J Biol Chem 2006; 282:1432-44. [PMID: 17098747 DOI: 10.1074/jbc.m605675200] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Replicative DNA polymerases, as exemplified by the B family polymerases from bacteriophages T4 and RB69, not only replicate DNA but also have the ability to proofread misincorporated nucleotides. Because the two activities reside in separate protein domains, polymerases must employ a mechanism that allows for efficient switching of the primer strand between the two active sites to achieve fast and accurate replication. Prior mutational and structural studies suggested that a beta hairpin structure located in the exonuclease domain of family B polymerases might play an important role in active site switching in the event of a nucleotide misincorporation. We show that deleting the beta hairpin loop in RB69 gp43 affects neither polymerase nor exonuclease activities. Single binding event studies with mismatched primer termini, however, show that the beta hairpin plays a role in maintaining the stability of the polymerase/DNA interactions during the binding of the primer DNA in the exonuclease active site but not on the return of the corrected primer to the polymerase active site. In addition, the deletion variant showed a more stable incorporation of a nucleotide opposite an abasic site. Moreover, in the 2.4 A crystal structure of the beta hairpin deletion variant incorporating an A opposite a templating furan, all four molecules in the crystal asymmetric unit have DNA in the polymerase active site, despite the presence of DNA distortions because of the misincorporation, confirming that the primer strand is not stably bound within the exonuclease active site in the absence of the beta hairpin loop.
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Affiliation(s)
- Matthew Hogg
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont 05405, USA
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16
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Longás E, de Vega M, Lázaro JM, Salas M. Functional characterization of highly processive protein-primed DNA polymerases from phages Nf and GA-1, endowed with a potent strand displacement capacity. Nucleic Acids Res 2006; 34:6051-63. [PMID: 17071961 PMCID: PMC1635332 DOI: 10.1093/nar/gkl769] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
This paper shows that the protein-primed DNA polymerases encoded by bacteriophages Nf and GA-1, unlike other DNA polymerases, do not require unwinding or processivity factors for efficient synthesis of full-length terminal protein (TP)-DNA. Analysis of their polymerization activity shows that both DNA polymerases base their replication efficiency on a high processivity and on the capacity to couple polymerization to strand displacement. Both enzymes are endowed with a proofreading activity that acts coordinately with the polymerization one to edit polymerization errors. Additionally, Nf double-stranded DNA binding protein (DBP) greatly stimulated the in vitro formation of the TP-dAMP initiation complex by decreasing the Km value for dATP of the Nf DNA polymerase by >20-fold. Whereas Nf DNA polymerase, as the φ29 enzyme, is able to use its homologous TP as well as DNA as primer, GA-1 DNA polymerase appears to have evolved to use its corresponding TP as the only primer of DNA synthesis. Such exceptional behaviour is discussed in the light of the recently solved structure of the DNA polymerase/TP complex of the related bacteriophage φ29.
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Affiliation(s)
| | | | | | - Margarita Salas
- To whom correspondence should be addressed. Tel: +344 91 4978436; Fax: +34 91 4978490;
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