1
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Ohtsubo Y, Kawahara S, Nagata Y. Clamping-mediated incorporation of single-stranded DNA with concomitant DNA synthesis by Taq polymerase involves nick-translation. Sci Rep 2024; 14:2030. [PMID: 38263346 PMCID: PMC10805873 DOI: 10.1038/s41598-024-52095-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 01/13/2024] [Indexed: 01/25/2024] Open
Abstract
The development and characterization of a new enzyme reaction contribute to advancements in modern biotechnology. Here, we report a novel CIS (clamping-mediated incorporation of single-stranded DNA with concomitant DNA synthesis) reaction catalyzed by Taq polymerase. In the reaction, a single-stranded DNA (ssDNA) with 3' Cs is attached with a preformed 3' G-tail of double-stranded DNA (dsDNA); DNA syntheses starting from both 3' ends result in the incorporation of ssDNA. A 3' G-tail length of 3 nucleotides adequately supports this reaction, indicating that Taq polymerase can clump short Watson-Crick base pairs as short as three pairs and use them to initiate DNA polymerization. The reverse transcriptase from Molony murine leukemia virus catalyzes strand displacement synthesis and produces flapped-end DNA, whereas the reaction by Taq polymerase involves the nick translation. These new reaction properties may be beneficial for the development of new molecular tools applicable in various fields. Apart from its CIS reaction activity, we also report that Taq polymerase has the undesirable characteristic of removing 5' fluorescent labels from dsDNA. This characteristic may have compromised various experiments involving the preparation of fluorescently-labeled dsDNA by PCR for a long time.
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Grants
- 19H02865 Ministry of Education, Culture, Sports, Science and Technology,Japan
- 22H02233 Ministry of Education, Culture, Sports, Science and Technology,Japan
- 22K19124 Ministry of Education, Culture, Sports, Science and Technology,Japan
- K-2016-004 Institute for Fermentation, Osaka,Japan
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Affiliation(s)
- Yoshiyuki Ohtsubo
- Department of Molecular and Chemical Life Sciences, Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Sendai, 980-8577, Japan.
| | - Syoutaro Kawahara
- Department of Molecular and Chemical Life Sciences, Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Sendai, 980-8577, Japan
| | - Yuji Nagata
- Department of Molecular and Chemical Life Sciences, Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Sendai, 980-8577, Japan
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2
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Calabrese S, Markl AM, Neugebauer M, Krauth SJ, Borst N, von Stetten F, Lehnert M. Reporter emission multiplexing in digital PCRs (REM-dPCRs): direct quantification of multiple target sequences per detection channel by population specific reporters. Analyst 2023; 148:5243-5254. [PMID: 37727114 DOI: 10.1039/d3an00191a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/21/2023]
Abstract
Digital PCRs (dPCRs) are widely used methods for the detection and quantification of rare abundant sequences relevant to fields such as liquid biopsy or oncology. In order to increase the information content and save valuable sample materials, there is a significant need for digital multiplexing methods that are easy to establish, analyse, and interpret, and ideally allow the usage of existing lab equipment. Herein, we present a novel reporter emission multiplexing approach for the digital PCR method (REM-dPCR), which meets these requirements. It further increases the multiplexing capacity of commercial dPCR devices. For example, we present a stepwise increase in multiplexing degrees from a monochrome two-plex assay in one detection channel to a six-plex REM-dPCR assay in a three-color dPCR device for KRAS/BRAF single nucleotide polymorphism (SNP) target sequences. The guidelines for the REM-dPCR design are presented, and the process from duplex to six-plex assay establishment, taking into account the target sequence-dependent effects on assay performance, is discussed. Furthermore, the assay-specific, sensitive and precise quantification of different fractions of KRAS mutant and wild-type DNA sequences in different ratios is demonstrated. To increase the device capacitance and the degree of multiplexing, the REM-dPCR uses the advantage of n target-independent reporter molecules in combination with target sequence-specific mediator probes. Different reporter types are labelled with fluorophores of different signal intensities but not necessarily different emission spectra. This leads to the generation of n independent single-positive populations in the dataspace, created by k detection channels, whereby n > k and n ≥ 2. By usage of target-independent but population-specific reporter types, a fixed set of six optimized signalling molecules could be defined. This reporter set enables the robust generation and precise differentiation of multiple fluorescence signals in dPCRs and can be transferred to new target panels. The set which enables stable signal generation and differentiation in a specified device would allow easy transfer to new target panels.
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Affiliation(s)
| | - Anja M Markl
- Hahn-Schickard, 79110 Freiburg, Germany.
- Faculty of Chemistry and Pharmacy, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
| | - Maximilian Neugebauer
- Hahn-Schickard, 79110 Freiburg, Germany.
- Laboratory for MEMS Applications, IMTEK-Department of Microsystems Engineering, University of Freiburg, 79110 Freiburg, Germany
| | - Stefanie J Krauth
- School of Biodiversity, One Health, and Veterinary Medicine, University of Glasgow, Glasgow, UK
- School of Health and Wellbeing, General Practice and Primary Care, University of Glasgow, Glasgow, UK
| | - Nadine Borst
- Hahn-Schickard, 79110 Freiburg, Germany.
- Laboratory for MEMS Applications, IMTEK-Department of Microsystems Engineering, University of Freiburg, 79110 Freiburg, Germany
| | - Felix von Stetten
- Hahn-Schickard, 79110 Freiburg, Germany.
- Laboratory for MEMS Applications, IMTEK-Department of Microsystems Engineering, University of Freiburg, 79110 Freiburg, Germany
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3
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Botto MM, Borsellini A, Lamers MH. A four-point molecular handover during Okazaki maturation. Nat Struct Mol Biol 2023; 30:1505-1515. [PMID: 37620586 DOI: 10.1038/s41594-023-01071-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Accepted: 07/17/2023] [Indexed: 08/26/2023]
Abstract
DNA replication introduces thousands of RNA primers into the lagging strand that need to be removed for replication to be completed. In Escherichia coli when the replicative DNA polymerase Pol IIIα terminates at a previously synthesized RNA primer, DNA Pol I takes over and continues DNA synthesis while displacing the downstream RNA primer. The displaced primer is subsequently excised by an endonuclease, followed by the sealing of the nick by a DNA ligase. Yet how the sequential actions of Pol IIIα, Pol I polymerase, Pol I endonuclease and DNA ligase are coordinated is poorly defined. Here we show that each enzymatic activity prepares the DNA substrate for the next activity, creating an efficient four-point molecular handover. The cryogenic-electron microscopy structure of Pol I bound to a DNA substrate with both an upstream and downstream primer reveals how it displaces the primer in a manner analogous to the monomeric helicases. Moreover, we find that in addition to its flap-directed nuclease activity, the endonuclease domain of Pol I also specifically cuts at the RNA-DNA junction, thus marking the end of the RNA primer and creating a 5' end that is a suitable substrate for the ligase activity of LigA once all RNA has been removed.
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Affiliation(s)
- Margherita M Botto
- Department of Cell and Chemical Biology, Leiden University Medical Center (LUMC), Leiden, the Netherlands
- Department of Molecular and Cellular Biology, Geneva University, Geneva, Switzerland
| | - Alessandro Borsellini
- Department of Cell and Chemical Biology, Leiden University Medical Center (LUMC), Leiden, the Netherlands
- Department of Structural Biology, Human Technopole, Milan, Italy
| | - Meindert H Lamers
- Department of Cell and Chemical Biology, Leiden University Medical Center (LUMC), Leiden, the Netherlands.
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4
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Yudkina A, Bulgakov N, Kim D, Baranova S, Ishchenko A, Saparbaev M, Koval V, Zharkov D. Abasic site-peptide cross-links are blocking lesions repaired by AP endonucleases. Nucleic Acids Res 2023; 51:6321-6336. [PMID: 37216593 PMCID: PMC10325907 DOI: 10.1093/nar/gkad423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 04/18/2023] [Accepted: 05/15/2023] [Indexed: 05/24/2023] Open
Abstract
Apurinic/apyrimidinic (AP) sites are abundant DNA lesions arising from spontaneous hydrolysis of the N-glycosidic bond and as base excision repair (BER) intermediates. AP sites and their derivatives readily trap DNA-bound proteins, resulting in DNA-protein cross-links. Those are subject to proteolysis but the fate of the resulting AP-peptide cross-links (APPXLs) is unclear. Here, we report two in vitro models of APPXLs synthesized by cross-linking of DNA glycosylases Fpg and OGG1 to DNA followed by trypsinolysis. The reaction with Fpg produces a 10-mer peptide cross-linked through its N-terminus, while OGG1 yields a 23-mer peptide attached through an internal lysine. Both adducts strongly blocked Klenow fragment, phage RB69 polymerase, Saccharolobus solfataricus Dpo4, and African swine fever virus PolX. In the residual lesion bypass, mostly dAMP and dGMP were incorporated by Klenow and RB69 polymerases, while Dpo4 and PolX used primer/template misalignment. Of AP endonucleases involved in BER, Escherichia coli endonuclease IV and its yeast homolog Apn1p efficiently hydrolyzed both adducts. In contrast, E. coli exonuclease III and human APE1 showed little activity on APPXL substrates. Our data suggest that APPXLs produced by proteolysis of AP site-trapped proteins may be removed by the BER pathway, at least in bacterial and yeast cells.
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Affiliation(s)
- Anna V Yudkina
- SB RAS Institute of Chemical Biology and Fundamental Medicine, Novosibirsk 630090, Russia
- Department of Natural Sciences, Novosibirsk State University, Novosibirsk 630090, Russia
| | - Nikita A Bulgakov
- SB RAS Institute of Chemical Biology and Fundamental Medicine, Novosibirsk 630090, Russia
| | - Daria V Kim
- SB RAS Institute of Chemical Biology and Fundamental Medicine, Novosibirsk 630090, Russia
- Department of Natural Sciences, Novosibirsk State University, Novosibirsk 630090, Russia
| | - Svetlana V Baranova
- SB RAS Institute of Chemical Biology and Fundamental Medicine, Novosibirsk 630090, Russia
| | - Alexander A Ishchenko
- Groupe “Mechanisms of DNA Repair and Carcinogenesis”, Equipe Labellisée LIGUE 2016, CNRS UMR9019, Université Paris-Saclay, Gustave Roussy Cancer Campus, F-94805 Villejuif, France
| | - Murat K Saparbaev
- Groupe “Mechanisms of DNA Repair and Carcinogenesis”, Equipe Labellisée LIGUE 2016, CNRS UMR9019, Université Paris-Saclay, Gustave Roussy Cancer Campus, F-94805 Villejuif, France
| | - Vladimir V Koval
- SB RAS Institute of Chemical Biology and Fundamental Medicine, Novosibirsk 630090, Russia
| | - Dmitry O Zharkov
- SB RAS Institute of Chemical Biology and Fundamental Medicine, Novosibirsk 630090, Russia
- Department of Natural Sciences, Novosibirsk State University, Novosibirsk 630090, Russia
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5
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Wang Y, Shi Y, Hellinga HW, Beese LS. Thermally controlled intein splicing of engineered DNA polymerases provides a robust and generalizable solution for accurate and sensitive molecular diagnostics. Nucleic Acids Res 2023; 51:5883-5894. [PMID: 37166959 PMCID: PMC10287962 DOI: 10.1093/nar/gkad368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 04/18/2023] [Accepted: 05/09/2023] [Indexed: 05/12/2023] Open
Abstract
DNA polymerases are essential for nucleic acid synthesis, cloning, sequencing and molecular diagnostics technologies. Conditional intein splicing is a powerful tool for controlling enzyme reactions. We have engineered a thermal switch into thermostable DNA polymerases from two structurally distinct polymerase families by inserting a thermally activated intein domain into a surface loop that is integral to the polymerase active site, thereby blocking DNA or RNA template access. The fusion proteins are inactive, but retain their structures, such that the intein excises during a heat pulse delivered at 70-80°C to generate spliced, active polymerases. This straightforward thermal activation step provides a highly effective, one-component 'hot-start' control of PCR reactions that enables accurate target amplification by minimizing unwanted by-products generated by off-target reactions. In one engineered enzyme, derived from Thermus aquaticus DNA polymerase, both DNA polymerase and reverse transcriptase activities are controlled by the intein, enabling single-reagent amplification of DNA and RNA under hot-start conditions. This engineered polymerase provides high-sensitivity detection for molecular diagnostics applications, amplifying 5-6 copies of the tested DNA and RNA targets with >95% certainty. The design principles used to engineer the inteins can be readily applied to construct other conditionally activated nucleic acid processing enzymes.
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Affiliation(s)
- You Wang
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
| | - Yuqian Shi
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
| | - Homme W Hellinga
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
| | - Lorena S Beese
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
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6
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Akram F, Shah FI, Ibrar R, Fatima T, Haq IU, Naseem W, Gul MA, Tehreem L, Haider G. Bacterial thermophilic DNA polymerases: A focus on prominent biotechnological applications. Anal Biochem 2023; 671:115150. [PMID: 37054862 DOI: 10.1016/j.ab.2023.115150] [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: 01/14/2023] [Revised: 02/24/2023] [Accepted: 04/03/2023] [Indexed: 04/15/2023]
Abstract
DNA polymerases are the enzymes able to replicate the genetic information in nucleic acid. As a result, they are necessary to copy the complete genome of every living creature before cell division and sustain the integrity of the genetic information throughout the life of each cell. Any organism that uses DNA as its genetic information, whether unicellular or multicellular, requires one or more thermostable DNA polymerases to thrive. Thermostable DNA polymerase is important in modern biotechnology and molecular biology because it results in methods such as DNA cloning, DNA sequencing, whole genome amplification, molecular diagnostics, polymerase chain reaction, synthetic biology, and single nucleotide polymorphism detection. There are at least 14 DNA-dependent DNA polymerases in the human genome, which is remarkable. These include the widely accepted, high-fidelity enzymes responsible for replicating the vast majority of genomic DNA and eight or more specialized DNA polymerases discovered in the last decade. The newly discovered polymerases' functions are still being elucidated. Still, one of its crucial tasks is to permit synthesis to resume despite the DNA damage that stops the progression of replication-fork. One of the primary areas of interest in the research field has been the quest for novel DNA polymerase since the unique features of each thermostable DNA polymerase may lead to the prospective creation of novel reagents. Furthermore, protein engineering strategies for generating mutant or artificial DNA polymerases have successfully generated potent DNA polymerases for various applications. In molecular biology, thermostable DNA polymerases are extremely useful for PCR-related methods. This article examines the role and importance of DNA polymerase in a variety of techniques.
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Affiliation(s)
- Fatima Akram
- Institute of Industrial Biotechnology, Government College University, Lahore, 54000, Pakistan.
| | - Fatima Iftikhar Shah
- Institute of Industrial Biotechnology, Government College University, Lahore, 54000, Pakistan; The University of Lahore, Pakistan
| | - Ramesha Ibrar
- Institute of Industrial Biotechnology, Government College University, Lahore, 54000, Pakistan
| | - Taseer Fatima
- Institute of Industrial Biotechnology, Government College University, Lahore, 54000, Pakistan
| | - Ikram Ul Haq
- Institute of Industrial Biotechnology, Government College University, Lahore, 54000, Pakistan; Pakistan Academy of Sciences, Islamabad, Pakistan
| | - Waqas Naseem
- Institute of Industrial Biotechnology, Government College University, Lahore, 54000, Pakistan
| | - Mahmood Ayaz Gul
- Institute of Industrial Biotechnology, Government College University, Lahore, 54000, Pakistan
| | - Laiba Tehreem
- Institute of Industrial Biotechnology, Government College University, Lahore, 54000, Pakistan
| | - Ghanoor Haider
- Institute of Industrial Biotechnology, Government College University, Lahore, 54000, Pakistan
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7
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Kim D, Lee J, Han J, Lim J, Lim EK, Kim E. A highly specific and flexible detection assay using collaborated actions of DNA-processing enzymes for identifying multiple gene expression signatures in breast cancer. Analyst 2023; 148:316-327. [PMID: 36484412 DOI: 10.1039/d2an01672a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Most nucleic acid biosensors employ nucleic acid-processing enzymes to bind, degrade, splice, synthesize, and modify nucleic acids. Utilizing their unique substrate preference, binding mode, and catalytic activity is of great importance in designing nucleic acid biosensors. Combination with DNA-processing enzymes enables them to transform into a new generation of molecular diagnostics tools with enhanced selectivity and sensitivity and reduced reaction time. Here, we report an isothermal amplification strategy by coemploying a structure-specific endonuclease (flap endonuclease 1, FEN1) and a strand-displacing DNA polymerase (Bst DNA polymerase) to detect long RNA targets. This approach couples the FEN1-driven invasive cleavage reaction with toehold-mediated rolling circle amplification (iFEN-tRCA), enabling the highly selective and rapid detection of long RNA targets and offering a detection limit below 10 pM within 1 h. We used two targets, such as human epidermal growth factor receptor 2 (HER2, encoded by ERBB2) and dopamine- and cyclic AMP-regulated phosphoprotein (DARPP, encoded by PPP1R1B), associated with prognosis or response to anticancer therapy. We demonstrated the feasibility and quantitative capability of the iFEN-tRCA assay by assessing the expression of two RNA transcripts (ERBB2 and PPP1R1B) with total RNA extracts purified from human breast cancer cells. Therefore, we envision that the developed assay will provide a suitable prognostic and diagnostic tool for identifying appropriate patients for HER2-targeted therapy and predicting the clinical outcome and occurrence of metastasis relapse in breast cancer.
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Affiliation(s)
- Dain Kim
- Department of Bioengineering & Nano-bioengineering, Research Center for Bio Materials and Process Development, Incheon National University, Incheon 22012, Republic of Korea.
| | - Jiyoung Lee
- Division of Bioengineering, Incheon National University, Incheon 22012, Republic of Korea
| | - Jueun Han
- Department of Chemistry, Incheon National University, Incheon 22012, Republic of Korea
| | - Jaewoo Lim
- BioNanotechnology Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Republic of Korea.
| | - Eun-Kyung Lim
- BioNanotechnology Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Republic of Korea. .,Department of Nanobiotechnology, KRIBB School of Biotechnology, UST, Daejeon 34113, Republic of Korea.,School of Pharmacy, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Eunjung Kim
- Department of Bioengineering & Nano-bioengineering, Research Center for Bio Materials and Process Development, Incheon National University, Incheon 22012, Republic of Korea. .,Division of Bioengineering, Incheon National University, Incheon 22012, Republic of Korea
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8
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Ahlqvist J, Linares-Pastén JA, Jasilionis A, Welin M, Håkansson M, Svensson LA, Wang L, Watzlawick H, Ævarsson A, Friðjónsson ÓH, Hreggviðsson GÓ, Ketelsen Striberny B, Glomsaker E, Lanes O, Al-Karadaghi S, Nordberg Karlsson E. Crystal structure of DNA polymerase I from Thermus phage G20c. ACTA CRYSTALLOGRAPHICA SECTION D STRUCTURAL BIOLOGY 2022; 78:1384-1398. [DOI: 10.1107/s2059798322009895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 10/10/2022] [Indexed: 11/06/2022]
Abstract
This study describes the structure of DNA polymerase I from Thermus phage G20c, termed PolI_G20c. This is the first structure of a DNA polymerase originating from a group of related thermophilic bacteriophages infecting Thermus thermophilus, including phages G20c, TSP4, P74-26, P23-45 and phiFA and the novel phage Tth15-6. Sequence and structural analysis of PolI_G20c revealed a 3′–5′ exonuclease domain and a DNA polymerase domain, and activity screening confirmed that both domains were functional. No functional 5′–3′ exonuclease domain was present. Structural analysis also revealed a novel specific structure motif, here termed SβαR, that was not previously identified in any polymerase belonging to the DNA polymerases I (or the DNA polymerase A family). The SβαR motif did not show any homology to the sequences or structures of known DNA polymerases. The exception was the sequence conservation of the residues in this motif in putative DNA polymerases encoded in the genomes of a group of thermophilic phages related to Thermus phage G20c. The structure of PolI_G20c was determined with the aid of another structure that was determined in parallel and was used as a model for molecular replacement. This other structure was of a 3′–5′ exonuclease termed ExnV1. The cloned and expressed gene encoding ExnV1 was isolated from a thermophilic virus metagenome that was collected from several hot springs in Iceland. The structure of ExnV1, which contains the novel SβαR motif, was first determined to 2.19 Å resolution. With these data at hand, the structure of PolI_G20c was determined to 2.97 Å resolution. The structures of PolI_G20c and ExnV1 are most similar to those of the Klenow fragment of DNA polymerase I (PDB entry 2kzz) from Escherichia coli, DNA polymerase I from Geobacillus stearothermophilus (PDB entry 1knc) and Taq polymerase (PDB entry 1bgx) from Thermus aquaticus.
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9
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Endutkin AV, Yudkina AV, Zharkov TD, Kim DV, Zharkov DO. Recognition of a Clickable Abasic Site Analog by DNA Polymerases and DNA Repair Enzymes. Int J Mol Sci 2022; 23:ijms232113353. [PMID: 36362137 PMCID: PMC9655677 DOI: 10.3390/ijms232113353] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 10/27/2022] [Accepted: 10/30/2022] [Indexed: 11/06/2022] Open
Abstract
Azide–alkyne cycloaddition (“click chemistry”) has found wide use in the analysis of molecular interactions in living cells. 5-ethynyl-2-(hydroxymethyl)tetrahydrofuran-3-ol (EAP) is a recently developed apurinic/apyrimidinic (AP) site analog functionalized with an ethynyl moiety, which can be introduced into cells in DNA constructs to perform labeling or cross-linking in situ. However, as a non-natural nucleoside, EAP could be subject to removal by DNA repair and misreading by DNA polymerases. Here, we investigate the interaction of this clickable AP site analog with DNA polymerases and base excision repair enzymes. Similarly to the natural AP site, EAP was non-instructive and followed the “A-rule”, directing residual but easily detectable incorporation of dAMP by E. coli DNA polymerase I Klenow fragment, bacteriophage RB69 DNA polymerase and human DNA polymerase β. On the contrary, EAP was blocking for DNA polymerases κ and λ. EAP was an excellent substrate for the major human AP endonuclease APEX1 and E. coli AP exonucleases Xth and Nfo but was resistant to the AP lyase activity of DNA glycosylases. Overall, our data indicate that EAP, once within a cell, would represent a replication block and would be removed through an AP endonuclease-initiated long-patch base excision repair pathway.
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Affiliation(s)
- Anton V. Endutkin
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., Novosibirsk 630090, Russia
- Correspondence: (A.V.E.); (D.O.Z.)
| | - Anna V. Yudkina
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., Novosibirsk 630090, Russia
| | - Timofey D. Zharkov
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., Novosibirsk 630090, Russia
| | - Daria V. Kim
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., Novosibirsk 630090, Russia
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogova Street, Novosibirsk 630090, Russia
| | - Dmitry O. Zharkov
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., Novosibirsk 630090, Russia
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogova Street, Novosibirsk 630090, Russia
- Correspondence: (A.V.E.); (D.O.Z.)
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10
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McLean EK, Nye TM, Lowder FC, Simmons LA. The Impact of RNA-DNA Hybrids on Genome Integrity in Bacteria. Annu Rev Microbiol 2022; 76:461-480. [PMID: 35655343 PMCID: PMC9527769 DOI: 10.1146/annurev-micro-102521-014450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/10/2023]
Abstract
During the essential processes of DNA replication and transcription, RNA-DNA hybrid intermediates are formed that pose significant risks to genome integrity when left unresolved. To manage RNA-DNA hybrids, all cells rely on RNase H family enzymes that specifically cleave the RNA portion of the many different types of hybrids that form in vivo. Recent experimental advances have provided new insight into how RNA-DNA hybrids form and the consequences to genome integrity that ensue when persistent hybrids remain unresolved. Here we review the types of RNA-DNA hybrids, including R-loops, RNA primers, and ribonucleotide misincorporations, that form during DNA replication and transcription and discuss how each type of hybrid can contribute to genome instability in bacteria. Further, we discuss how bacterial RNase HI, HII, and HIII and bacterial FEN enzymes contribute to genome maintenance through the resolution of hybrids.
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Affiliation(s)
- Emma K McLean
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA;
| | - Taylor M Nye
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA;
- Current affiliation: Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Frances C Lowder
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA;
| | - Lyle A Simmons
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA;
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11
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Muraru S, Muraru S, Nitu FR, Ionita M. Recent Efforts and Milestones for Simulating Nucleic Acid FRET Experiments through Computational Methods. J Chem Inf Model 2022; 62:232-239. [PMID: 35014791 DOI: 10.1021/acs.jcim.1c00957] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Computational methods can greatly aid nucleic acid fluorescence experiments by either offering fully detailed atomic insights into the conformations and interactions present in the studied system or by providing accurate simulations of the fundamental parameters. Fluorescence-based optical biosensors show great potential for clinical diagnosis of life-altering diseases with a very high specificity. Many of the designs for such rely on the concept of Förster resonance energy transfer (FRET). Currently, the methods used experimentally make use of theoretical assumptions which fundamentally affect the results. Having a detailed atomistic overview or significant simulated parameters could improve the understanding of the calculations and provide much more accurate outcomes. However, there are many challenges that need to be addressed before standardized computational protocols can be employed. This review is meant to highlight the progress made for computational methods used to simulate FRET experiments for nucleic acid probes. Recent advances have been made in computational tools, such as force field parametrizations and improved protocols. Complementary simulations to experimental data are also comprised in the this review.
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Affiliation(s)
- Sorin Muraru
- Faculty of Medical Engineering, University Politehnica of Bucharest, Gh. Polizu Street 1-7, 011061 Bucharest, Romania
| | - Sebastian Muraru
- Faculty of Medical Engineering, University Politehnica of Bucharest, Gh. Polizu Street 1-7, 011061 Bucharest, Romania
| | - Florentin Romeo Nitu
- Faculty of Medical Engineering, University Politehnica of Bucharest, Gh. Polizu Street 1-7, 011061 Bucharest, Romania
| | - Mariana Ionita
- Faculty of Medical Engineering, University Politehnica of Bucharest, Gh. Polizu Street 1-7, 011061 Bucharest, Romania.,Advanced Polymer Materials Group, University Polithenica of Bucharest, Gh. Polizu Street 1-7, 011061 Bucharest, Romania
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12
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Kesici MZ, Tinnefeld P, Vera AM. A simple and general approach to generate photoactivatable DNA processing enzymes. Nucleic Acids Res 2021; 50:e31. [PMID: 34904657 PMCID: PMC8989547 DOI: 10.1093/nar/gkab1212] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 11/08/2021] [Accepted: 11/25/2021] [Indexed: 11/29/2022] Open
Abstract
DNA processing enzymes, such as DNA polymerases and endonucleases, have found many applications in biotechnology, molecular diagnostics, and synthetic biology, among others. The development of enzymes with controllable activity, such as hot-start or light-activatable versions, has boosted their applications and improved the sensitivity and specificity of the existing ones. However, current approaches to produce controllable enzymes are experimentally demanding to develop and case-specific. Here, we introduce a simple and general method to design light-start DNA processing enzymes. In order to prove its versatility, we applied our method to three DNA polymerases commonly used in biotechnology, including the Phi29 (mesophilic), Taq, and Pfu polymerases, and one restriction enzyme. Light-start enzymes showed suppressed polymerase, exonuclease, and endonuclease activity until they were re-activated by an UV pulse. Finally, we applied our enzymes to common molecular biology assays and showed comparable performance to commercial hot-start enzymes.
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Affiliation(s)
- Merve-Zeynep Kesici
- Department of Chemistry and Center for NanoScience, Ludwig-Maximilians-Universität München, München 81377, Germany
| | - Philip Tinnefeld
- Department of Chemistry and Center for NanoScience, Ludwig-Maximilians-Universität München, München 81377, Germany
| | - Andrés Manuel Vera
- Department of Chemistry and Center for NanoScience, Ludwig-Maximilians-Universität München, München 81377, Germany
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13
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Schlenker F, Kipf E, Deuter M, Höffkes I, Lehnert M, Zengerle R, von Stetten F, Scherer F, Wehrle J, von Bubnoff N, Juelg P, Hutzenlaub T, Borst N. Stringent Base Specific and Optimization-Free Multiplex Mediator Probe ddPCR for the Quantification of Point Mutations in Circulating Tumor DNA. Cancers (Basel) 2021; 13:cancers13225742. [PMID: 34830896 PMCID: PMC8616434 DOI: 10.3390/cancers13225742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/12/2021] [Accepted: 11/13/2021] [Indexed: 11/21/2022] Open
Abstract
Simple Summary Cancer treatment strategies and their follow-up monitoring are changing to personalized therapies, based on molecular genetic information from the individual person. Liquid biopsy, where this molecular information is derived from body fluids such as blood, has the potential to provide a systemic fingerprint of cancer dynamics, and, compared to tissue biopsy, is much less invasive for the patient. We used the previously published mediator probe PCR technology for liquid biopsy detection of several mutations in one reaction, so-called digital multiplex PCR. Quantification of point mutations in plasma eluates from follow-up patients using 4-plex digital assays showed a comparable performance to reference 2-plex assays. As a key feature, the presented multiplex assays require no laborious optimization as they use the same concentrations and cycling conditions for all targets. This allows for flexible design and interchangeable target panels, thus the assay is easily adaptable for individual patient monitoring and reduces sample consumption. Abstract There is an increasing demand for optimization-free multiplex assays to rapidly establish comprehensive target panels for cancer monitoring by liquid biopsy. We present the mediator probe (MP) PCR for the quantification of the seven most frequent point mutations and corresponding wild types (KRAS and BRAF) in colorectal carcinoma. Standardized parameters for the digital assay were derived using design of experiments. Without further optimization, the limit of detection (LoD) was determined through spiking experiments with synthetic mutant DNA in human genomic DNA. The limit of blank (LoB) was measured in cfDNA plasma eluates from healthy volunteers. The 2-plex and 4-plex MP ddPCR assays showed a LoB of 0 copies/mL except for 4-plex KRAS G13D (9.82 copies/mL) and 4-plex BRAF V600E (16.29 copies/mL) and allele frequencies of 0.004% ≤ LoD ≤ 0.38% with R2 ≥ 0.98. The quantification of point mutations in patient plasma eluates (18 patients) during follow-up using the 4-plex MP ddPCR showed a comparable performance to the reference assays. The presented multiplex assays need no laborious optimization, as they use the same concentrations and cycling conditions for all targets. This facilitates assay certification, allows a fast and flexible design process, and is thus easily adaptable for individual patient monitoring.
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Affiliation(s)
- Franziska Schlenker
- Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany; (F.S.); (E.K.); (I.H.); (M.L.); (R.Z.); (F.v.S.); (P.J.); (T.H.)
| | - Elena Kipf
- Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany; (F.S.); (E.K.); (I.H.); (M.L.); (R.Z.); (F.v.S.); (P.J.); (T.H.)
| | - Max Deuter
- Department of Medicine I, Medical Center—University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany; (M.D.); (F.S.); (J.W.); (N.v.B.)
| | - Inga Höffkes
- Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany; (F.S.); (E.K.); (I.H.); (M.L.); (R.Z.); (F.v.S.); (P.J.); (T.H.)
| | - Michael Lehnert
- Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany; (F.S.); (E.K.); (I.H.); (M.L.); (R.Z.); (F.v.S.); (P.J.); (T.H.)
| | - Roland Zengerle
- Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany; (F.S.); (E.K.); (I.H.); (M.L.); (R.Z.); (F.v.S.); (P.J.); (T.H.)
- Laboratory for MEMS Applications, IMTEK—Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany
| | - Felix von Stetten
- Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany; (F.S.); (E.K.); (I.H.); (M.L.); (R.Z.); (F.v.S.); (P.J.); (T.H.)
- Laboratory for MEMS Applications, IMTEK—Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany
| | - Florian Scherer
- Department of Medicine I, Medical Center—University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany; (M.D.); (F.S.); (J.W.); (N.v.B.)
| | - Julius Wehrle
- Department of Medicine I, Medical Center—University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany; (M.D.); (F.S.); (J.W.); (N.v.B.)
| | - Nikolas von Bubnoff
- Department of Medicine I, Medical Center—University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany; (M.D.); (F.S.); (J.W.); (N.v.B.)
- Department of Hematology and Oncology, Campus Lübeck, University Hospital Schleswig-Holstein, 23562 Lübeck, Germany
| | - Peter Juelg
- Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany; (F.S.); (E.K.); (I.H.); (M.L.); (R.Z.); (F.v.S.); (P.J.); (T.H.)
| | - Tobias Hutzenlaub
- Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany; (F.S.); (E.K.); (I.H.); (M.L.); (R.Z.); (F.v.S.); (P.J.); (T.H.)
- Laboratory for MEMS Applications, IMTEK—Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany
| | - Nadine Borst
- Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany; (F.S.); (E.K.); (I.H.); (M.L.); (R.Z.); (F.v.S.); (P.J.); (T.H.)
- Laboratory for MEMS Applications, IMTEK—Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany
- Correspondence: ; Tel.: +49-761-203-73208
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14
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Boone M, Ramasamy P, Zuallaert J, Bouwmeester R, Van Moer B, Maddelein D, Turan D, Hulstaert N, Eeckhaut H, Vandermarliere E, Martens L, Degroeve S, De Neve W, Vranken W, Callewaert N. Massively parallel interrogation of protein fragment secretability using SECRiFY reveals features influencing secretory system transit. Nat Commun 2021; 12:6414. [PMID: 34741024 PMCID: PMC8571348 DOI: 10.1038/s41467-021-26720-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 10/15/2021] [Indexed: 11/09/2022] Open
Abstract
While transcriptome- and proteome-wide technologies to assess processes in protein biogenesis are now widely available, we still lack global approaches to assay post-ribosomal biogenesis events, in particular those occurring in the eukaryotic secretory system. We here develop a method, SECRiFY, to simultaneously assess the secretability of >105 protein fragments by two yeast species, S. cerevisiae and P. pastoris, using custom fragment libraries, surface display and a sequencing-based readout. Screening human proteome fragments with a median size of 50-100 amino acids, we generate datasets that enable datamining into protein features underlying secretability, revealing a striking role for intrinsic disorder and chain flexibility. The SECRiFY methodology generates sufficient amounts of annotated data for advanced machine learning methods to deduce secretability patterns. The finding that secretability is indeed a learnable feature of protein sequences provides a solid base for application-focused studies.
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Affiliation(s)
- Morgane Boone
- Center for Medical Biotechnology, VIB, Zwijnaarde, Belgium. .,Department of Biochemistry and Microbiology, Faculty of Sciences, Ghent University, Ghent, Belgium. .,Department of Biochemistry and Biophysics, UCSF, San Francisco, CA, USA.
| | - Pathmanaban Ramasamy
- grid.11486.3a0000000104788040Center for Medical Biotechnology, VIB, Zwijnaarde, Belgium ,grid.5342.00000 0001 2069 7798Department of Biomolecular Medicine, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium ,grid.8767.e0000 0001 2290 8069Structural Biology Brussels, VUB, Brussels, Belgium ,grid.11486.3a0000000104788040Structural Biology Research Center, VIB, Brussels, Belgium ,Interuniversity Institute of Bioinformatics in Brussels (IB)2, ULB-VUB, Brussels, Belgium
| | - Jasper Zuallaert
- grid.11486.3a0000000104788040Center for Medical Biotechnology, VIB, Zwijnaarde, Belgium ,grid.5342.00000 0001 2069 7798Department of Biochemistry and Microbiology, Faculty of Sciences, Ghent University, Ghent, Belgium ,grid.510328.dCenter for Biotech Data Science, Ghent University Global Campus, Songdo, Incheon, South Korea ,grid.5342.00000 0001 2069 7798IDLab, ELIS, UGent, Ghent, Belgium
| | - Robbin Bouwmeester
- grid.11486.3a0000000104788040Center for Medical Biotechnology, VIB, Zwijnaarde, Belgium ,grid.5342.00000 0001 2069 7798Department of Biomolecular Medicine, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Berre Van Moer
- grid.11486.3a0000000104788040Center for Medical Biotechnology, VIB, Zwijnaarde, Belgium ,grid.5342.00000 0001 2069 7798Department of Biochemistry and Microbiology, Faculty of Sciences, Ghent University, Ghent, Belgium
| | - Davy Maddelein
- grid.11486.3a0000000104788040Center for Medical Biotechnology, VIB, Zwijnaarde, Belgium ,grid.5342.00000 0001 2069 7798Department of Biomolecular Medicine, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Demet Turan
- grid.11486.3a0000000104788040Center for Medical Biotechnology, VIB, Zwijnaarde, Belgium ,grid.5342.00000 0001 2069 7798Department of Biomolecular Medicine, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Niels Hulstaert
- grid.11486.3a0000000104788040Center for Medical Biotechnology, VIB, Zwijnaarde, Belgium ,grid.5342.00000 0001 2069 7798Department of Biomolecular Medicine, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Hannah Eeckhaut
- grid.11486.3a0000000104788040Center for Medical Biotechnology, VIB, Zwijnaarde, Belgium ,grid.5342.00000 0001 2069 7798Department of Biochemistry and Microbiology, Faculty of Sciences, Ghent University, Ghent, Belgium
| | - Elien Vandermarliere
- grid.11486.3a0000000104788040Center for Medical Biotechnology, VIB, Zwijnaarde, Belgium ,grid.5342.00000 0001 2069 7798Department of Biomolecular Medicine, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Lennart Martens
- grid.11486.3a0000000104788040Center for Medical Biotechnology, VIB, Zwijnaarde, Belgium ,grid.5342.00000 0001 2069 7798Department of Biomolecular Medicine, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Sven Degroeve
- grid.11486.3a0000000104788040Center for Medical Biotechnology, VIB, Zwijnaarde, Belgium ,grid.5342.00000 0001 2069 7798Department of Biomolecular Medicine, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Wesley De Neve
- grid.510328.dCenter for Biotech Data Science, Ghent University Global Campus, Songdo, Incheon, South Korea ,grid.5342.00000 0001 2069 7798IDLab, ELIS, UGent, Ghent, Belgium
| | - Wim Vranken
- grid.8767.e0000 0001 2290 8069Structural Biology Brussels, VUB, Brussels, Belgium ,grid.11486.3a0000000104788040Structural Biology Research Center, VIB, Brussels, Belgium ,Interuniversity Institute of Bioinformatics in Brussels (IB)2, ULB-VUB, Brussels, Belgium
| | - Nico Callewaert
- Center for Medical Biotechnology, VIB, Zwijnaarde, Belgium. .,Department of Biochemistry and Microbiology, Faculty of Sciences, Ghent University, Ghent, Belgium.
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15
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Kipf E, Schlenker F, Borst N, Fillies M, Kirschner-Schwabe R, Zengerle R, Eckert C, von Stetten F, Lehnert M. Advanced Minimal Residual Disease Monitoring for Acute Lymphoblastic Leukemia with Multiplex Mediator Probe PCR. J Mol Diagn 2021; 24:57-68. [PMID: 34757015 DOI: 10.1016/j.jmoldx.2021.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 09/16/2021] [Accepted: 10/04/2021] [Indexed: 10/20/2022] Open
Abstract
Acute lymphoblastic leukemia (ALL) is the most frequent malignancy in childhood. Minimal residual disease (MRD) monitoring is an important prognostic factor for treatment response and patient stratification. It uses personalized real-time PCR to measure the amount of cancer cells among normal cells. Due to clonal tumor evolution or secondary rearrangement processes, MRD markers can disappear during treatment, leading to false-negative MRD results and wrong decision-making in personalized treatments. Therefore, monitoring of multiple MRD markers per patient is required. For the first time, the authors present personalized multiplex mediator probe PCR (MP PCR) for MRD monitoring in ALL. These assays can precisely quantify more MRD markers in less sample material. Therefore, clinical outcomes will be less affected by clonal tumor evolution. Personalized duplex MP PCR assays were developed for different genomic MRD markers, including immunoglobulin/T-cell receptor gene rearrangements, gene fusions, and gene deletions. One duplex assay was successfully applied in a prospective patient case and compared with hydrolysis probes. Moreover, the authors increased the multiplex level from duplex to 4-plex and still met the EuroMRD requirements for reliable quantification. In addition, the authors' MRD-MP design guidelines and multiplex workflow facilitate and accelerate MP PCR assay development. This helps the standardization of personal diagnostics.
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Affiliation(s)
- Elena Kipf
- Hahn-Schickard, Freiburg, Germany; Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering, University of Freiburg, Freiburg, Germany
| | | | - Nadine Borst
- Hahn-Schickard, Freiburg, Germany; Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering, University of Freiburg, Freiburg, Germany
| | - Marion Fillies
- Department of Pediatric Oncology/Hematology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Renate Kirschner-Schwabe
- Department of Pediatric Oncology/Hematology, Charité - Universitätsmedizin Berlin, Berlin, Germany; German Cancer Consortium (DKTK) and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Roland Zengerle
- Hahn-Schickard, Freiburg, Germany; Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering, University of Freiburg, Freiburg, Germany
| | - Cornelia Eckert
- Department of Pediatric Oncology/Hematology, Charité - Universitätsmedizin Berlin, Berlin, Germany; German Cancer Consortium (DKTK) and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Felix von Stetten
- Hahn-Schickard, Freiburg, Germany; Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering, University of Freiburg, Freiburg, Germany.
| | - Michael Lehnert
- Hahn-Schickard, Freiburg, Germany; Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering, University of Freiburg, Freiburg, Germany
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16
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Yi X, Khey J, Kazlauskas RJ, Travisano M. Plasmid hypermutation using a targeted artificial DNA replisome. SCIENCE ADVANCES 2021; 7:7/29/eabg8712. [PMID: 34272238 PMCID: PMC8284885 DOI: 10.1126/sciadv.abg8712] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 06/02/2021] [Indexed: 06/13/2023]
Abstract
Extensive exploration of a protein's sequence space for improved or new molecular functions requires in vivo evolution with large populations. But disentangling the evolution of a target protein from the rest of the proteome is challenging. Here, we designed a protein complex of a targeted artificial DNA replisome (TADR) that operates in live cells to processively replicate one strand of a plasmid with errors. It enhanced mutation rates of the target plasmid up to 2.3 × 105-fold with only a 78-fold increase in off-target mutagenesis. It was used to evolve itself to increase error rate and increase the efficiency of an efflux pump while simultaneously expanding the substrate repertoire. TADR enables multiple simultaneous substitutions to discover functions inaccessible by accumulating single substitutions, affording potential for solving hard problems in molecular evolution and developing biologic drugs and industrial catalysts.
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Affiliation(s)
- Xiao Yi
- BioTechnology Institute, University of Minnesota, Minneapolis, MN, USA.
| | - Joleen Khey
- Department of Plant and Microbial Biology, University of Minnesota, Minneapolis, MN, USA
| | - Romas J Kazlauskas
- BioTechnology Institute, University of Minnesota, Minneapolis, MN, USA.
- Department of Biochemistry Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Michael Travisano
- BioTechnology Institute, University of Minnesota, Minneapolis, MN, USA.
- Department of Ecology Evolution and Behavior, University of Minnesota, Minneapolis, MN, USA
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17
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Basu S, Mallik S, Hait S, Kundu S. Genome-scale molecular principles of mRNA half-life regulation in yeast. FEBS J 2020; 288:3428-3447. [PMID: 33319437 DOI: 10.1111/febs.15670] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 11/07/2020] [Accepted: 12/11/2020] [Indexed: 12/22/2022]
Abstract
Precise control of protein and messenger RNA (mRNA) degradation is essential for cellular metabolism and homeostasis. Controlled and specific degradation of both molecular species necessitates their engagements with the respective degradation machineries; this engagement involves a disordered/unstructured segment of the substrate traversing the degradation tunnel of the machinery and accessing the catalytic sites. However, while molecular factors influencing protein degradation have been extensively explored on a genome scale, and in multiple organisms, such a comprehensive understanding remains missing for mRNAs. Here, we analyzed multiple genome-scale experimental yeast mRNA half-life data in light of experimentally derived mRNA secondary structures and protein binding data, along with high-resolution X-ray crystallographic structures of the RNase machines. Results unraveled a consistent genome-scale trend that mRNAs comprising longer terminal and/or internal unstructured segments have significantly shorter half-lives; the lengths of the 5'-terminal, 3'-terminal, and internal unstructured segments that affect mRNA half-life are compatible with molecular structures of the 5' exo-, 3' exo-, and endoribonuclease machineries. Sequestration into ribonucleoprotein complexes elongates mRNA half-life, presumably by burying ribonuclease engagement sites under oligomeric interfaces. After gene duplication, differences in terminal unstructured lengths, proportions of internal unstructured segments, and oligomerization modes result in significantly altered half-lives of paralogous mRNAs. Side-by-side comparison of molecular principles underlying controlled protein and mRNA degradation in yeast unravels their remarkable mechanistic similarities and suggests how the intrinsic structural features of the two molecular species, at two different levels of the central dogma, regulate their half-lives on genome scale.
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Affiliation(s)
- Sudipto Basu
- Department of Biophysics, Molecular Biology and Bioinformatics, University of Calcutta, Kolkata, India.,Center of Excellence in Systems Biology and Biomedical Engineering (TEQIP Phase-III), University of Calcutta, Kolkata, India
| | - Saurav Mallik
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Suman Hait
- Department of Biophysics, Molecular Biology and Bioinformatics, University of Calcutta, Kolkata, India
| | - Sudip Kundu
- Department of Biophysics, Molecular Biology and Bioinformatics, University of Calcutta, Kolkata, India.,Center of Excellence in Systems Biology and Biomedical Engineering (TEQIP Phase-III), University of Calcutta, Kolkata, India
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18
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Displacement of Slow-Turnover DNA Glycosylases by Molecular Traffic on DNA. Genes (Basel) 2020; 11:genes11080866. [PMID: 32751599 PMCID: PMC7465369 DOI: 10.3390/genes11080866] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 07/25/2020] [Accepted: 07/28/2020] [Indexed: 12/20/2022] Open
Abstract
In the base excision repair pathway, the initiating enzymes, DNA glycosylases, remove damaged bases and form long-living complexes with the abasic DNA product, but can be displaced by AP endonucleases. However, many nuclear proteins can move along DNA, either actively (such as DNA or RNA polymerases) or by passive one-dimensional diffusion. In most cases, it is not clear whether this movement is disturbed by other bound proteins or how collisions with moving proteins affect the bound proteins, including DNA glycosylases. We have used a two-substrate system to study the displacement of human OGG1 and NEIL1 DNA glycosylases by DNA polymerases in both elongation and diffusion mode and by D4, a passively diffusing subunit of a viral DNA polymerase. The OGG1–DNA product complex was disrupted by DNA polymerase β (POLβ) in both elongation and diffusion mode, Klenow fragment (KF) in the elongation mode and by D4. NEIL1, which has a shorter half-life on DNA, was displaced more efficiently. Hence, both possibly specific interactions with POLβ and nonspecific collisions (KF, D4) can displace DNA glycosylases from DNA. The protein movement along DNA was blocked by very tightly bound Cas9 RNA-targeted nuclease, providing an upper limit on the efficiency of obstacle clearance.
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19
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Expression and functional study of VpV262 Pol, a moderately halophilic DNA polymerase from the Vibrio parahaemolyticus phage VpV262. Enzyme Microb Technol 2020; 139:109588. [PMID: 32732037 DOI: 10.1016/j.enzmictec.2020.109588] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 04/24/2020] [Accepted: 04/27/2020] [Indexed: 11/20/2022]
Abstract
Halophilic organisms are found widely in environments where the salt concentration is higher than 0.2 M. Halophilic proteins isolated from these organisms maintain structural integrity and function under high salt stress, whereas their non-halophilic homologs tend to aggregate and collapse. Here we report for the first time the expression and function of a DNA polymerase (DNAPol) VpV262 Pol, which belongs to DNAPol Family A from Vibrio parahaemolyticus phage VpV262. Enzymatic activity assay revealed that VpV262 Pol possessed 5'-3' polymerase activity as well as 3'-5' proofreading exonuclease activity. VpV262 Pol requires Mg2+ or Mn2+ to catalyze the polymerization reaction. Polymerization activity assay under a wide range of salt concentrations showed that VpV262 Pol maintains the highest polymerase activity with 0-0.3 M of NaCl/KCl and 0-0.5 M KAc (potassium acetate) /KGlc (potassium gluconate) when treated with 0-1 M corresponding salts, in contrast to significantly decreased activity of Phi29 Pol and Taq Pol above 0.2 M. Consistent with typical features of other halophilic proteins, negatively-charged amino acids are more frequently distributed on the surface of VpV262 Pol, contributing to highly solubility and enhanced halotolerance. While 3D-Structure of VpV262 Pol needs to be confirmed by experimental data further, this study here has added a member for the relatively small family of halotolerant DNA polymerase, and provides a valuable reference in isolation and characterization of DNA polymerases from halophilic organisms.
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20
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Ghosh S, Goldgur Y, Shuman S. Mycobacterial DNA polymerase I: activities and crystal structures of the POL domain as apoenzyme and in complex with a DNA primer-template and of the full-length FEN/EXO-POL enzyme. Nucleic Acids Res 2020; 48:3165-3180. [PMID: 32034423 PMCID: PMC7102940 DOI: 10.1093/nar/gkaa075] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 01/23/2020] [Accepted: 02/06/2020] [Indexed: 02/06/2023] Open
Abstract
Mycobacterial Pol1 is a bifunctional enzyme composed of an N-terminal DNA flap endonuclease/5' exonuclease domain (FEN/EXO) and a C-terminal DNA polymerase domain (POL). Here we document additional functions of Pol1: FEN activity on the flap RNA strand of an RNA:DNA hybrid and reverse transcriptase activity on a DNA-primed RNA template. We report crystal structures of the POL domain, as apoenzyme and as ternary complex with 3'-dideoxy-terminated DNA primer-template and dNTP. The thumb, palm, and fingers subdomains of POL form an extensive interface with the primer-template and the triphosphate of the incoming dNTP. Progression from an open conformation of the apoenzyme to a nearly closed conformation of the ternary complex entails a disordered-to-ordered transition of several segments of the thumb and fingers modules and an inward motion of the fingers subdomain-especially the O helix-to engage the primer-template and dNTP triphosphate. Distinctive structural features of mycobacterial Pol1 POL include a manganese binding site in the vestigial 3' exonuclease subdomain and a non-catalytic water-bridged magnesium complex at the protein-DNA interface. We report a crystal structure of the bifunctional FEN/EXO-POL apoenzyme that reveals the positions of two active site metals in the FEN/EXO domain.
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Affiliation(s)
- Shreya Ghosh
- Molecular Biology Program, Sloan-Kettering Institute, New York, NY 10065, USA
| | - Yehuda Goldgur
- Structural Biology Program, Sloan-Kettering Institute, New York, NY 10065, USA
| | - Stewart Shuman
- Molecular Biology Program, Sloan-Kettering Institute, New York, NY 10065, USA
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21
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Lee J. Development and Evolution of Molecular Markers and Genetic Maps in Capsicum Species. COMPENDIUM OF PLANT GENOMES 2019. [DOI: 10.1007/978-3-319-97217-6_5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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22
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Kolganova NA, Vasiliskov VA, Kuznetsova VE, Shershov VE, Lapa SA, Guseinov TO, Spitsyn MA, Timofeev EN, Chudinov AV. Factors Affecting the Tailing of Blunt End DNA with Fluorescent Pyrimidine dNTPs. Mol Biotechnol 2018; 60:879-886. [PMID: 30244435 DOI: 10.1007/s12033-018-0124-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The transferase activity of non-proofreading DNA polymerases is a well-known phenomenon that has been utilized in cloning and sequencing applications. The non-templated addition of modified nucleotides at DNA blunt ends is a potentially useful feature of DNA polymerases that can be used for selective transformation of DNA 3' ends. In this paper, we characterized the tailing reaction at perfectly matched and mismatched duplex ends with Cy3- and Cy5-modified pyrimidine nucleotides. It was shown that the best DNA tailing substrate does not have a perfect Watson-Crick base pair at the end. Mismatched duplexes with a 3' dC were the most efficient in the Taq DNA polymerase-catalysed tailing reaction with a Cy5-modified dUTP. We further demonstrated that the arrangement of the dye residue relative to the nucleobase notably affects the outcome of the tailing reaction. A comparative study of labelled deoxycytidine and deoxyuridine nucleotides showed higher efficiency for dUTP derivatives. The non-templated addition of modified nucleotides by Taq polymerase at a duplex blunt end was generally complicated by the pyrophosphorolysis and 5' exonuclease activity of the enzyme.
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Affiliation(s)
- Natalia A Kolganova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Street 32, Moscow, Russia, 119991
| | - Vadim A Vasiliskov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Street 32, Moscow, Russia, 119991
| | - Viktoriya E Kuznetsova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Street 32, Moscow, Russia, 119991
| | - Valeriy E Shershov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Street 32, Moscow, Russia, 119991
| | - Sergey A Lapa
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Street 32, Moscow, Russia, 119991
| | - Timur O Guseinov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Street 32, Moscow, Russia, 119991
| | - Maksim A Spitsyn
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Street 32, Moscow, Russia, 119991
| | - Edward N Timofeev
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Street 32, Moscow, Russia, 119991.
| | - Alexander V Chudinov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Street 32, Moscow, Russia, 119991
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23
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Liu Y, Freeman ADJ, Déclais AC, Lilley DMJ. A monovalent ion in the DNA binding interface of the eukaryotic junction-resolving enzyme GEN1. Nucleic Acids Res 2018; 46:11089-11098. [PMID: 30247722 PMCID: PMC6237754 DOI: 10.1093/nar/gky863] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 09/11/2018] [Accepted: 09/13/2018] [Indexed: 01/07/2023] Open
Abstract
GEN1 is a member of the FEN/EXO family of structure-selective nucleases that cleave 1 nt 3' to a variety of branchpoints. For each, the H2TH motif binds a monovalent ion and plays an important role in binding one helical arm of the substrates. We investigate here the importance of this metal ion on substrate specificity and GEN1 structure. In the presence of K+ ions the substrate specificity is wider than in Na+, yet four-way junctions remain the preferred substrate. In a combination of K+ and Mg2+ second strand cleavage is accelerated 17-fold, ensuring bilateral cleavage of the junction. We have solved crystal structures of Chaetomium thermophilum GEN1 with Cs+, K+ and Na+ bound. With bound Cs+ the loop of the H2TH motif extends toward the active site so that D199 coordinates a Mg2+, buttressed by an interaction of the adjacent Y200. With the lighter ions bound the H2TH loop changes conformation and retracts away from the active site. We hypothesize this conformational change might play a role in second strand cleavage acceleration.
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Affiliation(s)
- Yijin Liu
- Cancer Research UK Nucleic Acid Structure Research Group, MSI/WTB Complex, The University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Alasdair DJ Freeman
- Cancer Research UK Nucleic Acid Structure Research Group, MSI/WTB Complex, The University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Anne-Cécile Déclais
- Cancer Research UK Nucleic Acid Structure Research Group, MSI/WTB Complex, The University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - David M J Lilley
- Cancer Research UK Nucleic Acid Structure Research Group, MSI/WTB Complex, The University of Dundee, Dow Street, Dundee DD1 5EH, UK
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24
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Uson ML, Carl A, Goldgur Y, Shuman S. Crystal structure and mutational analysis of Mycobacterium smegmatis FenA highlight active site amino acids and three metal ions essential for flap endonuclease and 5' exonuclease activities. Nucleic Acids Res 2018; 46:4164-4175. [PMID: 29635474 PMCID: PMC5934675 DOI: 10.1093/nar/gky238] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 03/19/2018] [Accepted: 03/21/2018] [Indexed: 02/02/2023] Open
Abstract
Mycobacterium smegmatis FenA is a nucleic acid phosphodiesterase with flap endonuclease and 5' exonuclease activities. The 1.8 Å crystal structure of FenA reported here highlights as its closest homologs bacterial FEN-family enzymes ExoIX, the Pol1 exonuclease domain and phage T5 Fen. Mycobacterial FenA assimilates three active site manganese ions (M1, M2, M3) that are coordinated, directly and via waters, to a constellation of eight carboxylate side chains. We find via mutagenesis that the carboxylate contacts to all three manganese ions are essential for FenA's activities. Structures of nuclease-dead FenA mutants D125N, D148N and D208N reveal how they fail to bind one of the three active site Mn2+ ions, in a distinctive fashion for each Asn change. The structure of FenA D208N with a phosphate anion engaged by M1 and M2 in a state mimetic of a product complex suggests a mechanism for metal-catalyzed phosphodiester hydrolysis similar to that proposed for human Exo1. A distinctive feature of FenA is that it does not have the helical arch module found in many other FEN/FEN-like enzymes. Instead, this segment of FenA adopts a unique structure comprising a short 310 helix and surface β-loop that coordinates a fourth manganese ion (M4).
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Affiliation(s)
- Maria Loressa Uson
- Molecular Biology Program, Sloan-Kettering Institute, New York, NY 10065, USA
| | - Ayala Carl
- Molecular Biology Program, Sloan-Kettering Institute, New York, NY 10065, USA
| | - Yehuda Goldgur
- Structural Biology Program, Sloan-Kettering Institute, New York, NY 10065, USA
| | - Stewart Shuman
- Molecular Biology Program, Sloan-Kettering Institute, New York, NY 10065, USA
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25
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Boone M, De Koker A, Callewaert N. Capturing the 'ome': the expanding molecular toolbox for RNA and DNA library construction. Nucleic Acids Res 2018; 46:2701-2721. [PMID: 29514322 PMCID: PMC5888575 DOI: 10.1093/nar/gky167] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2017] [Revised: 02/05/2018] [Accepted: 02/23/2018] [Indexed: 12/14/2022] Open
Abstract
All sequencing experiments and most functional genomics screens rely on the generation of libraries to comprehensively capture pools of targeted sequences. In the past decade especially, driven by the progress in the field of massively parallel sequencing, numerous studies have comprehensively assessed the impact of particular manipulations on library complexity and quality, and characterized the activities and specificities of several key enzymes used in library construction. Fortunately, careful protocol design and reagent choice can substantially mitigate many of these biases, and enable reliable representation of sequences in libraries. This review aims to guide the reader through the vast expanse of literature on the subject to promote informed library generation, independent of the application.
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Affiliation(s)
- Morgane Boone
- Center for Medical Biotechnology, VIB, Zwijnaarde 9052, Belgium
- Department of Biochemistry and Microbiology, Ghent University, Ghent 9000, Belgium
| | - Andries De Koker
- Center for Medical Biotechnology, VIB, Zwijnaarde 9052, Belgium
- Department of Biochemistry and Microbiology, Ghent University, Ghent 9000, Belgium
| | - Nico Callewaert
- Center for Medical Biotechnology, VIB, Zwijnaarde 9052, Belgium
- Department of Biochemistry and Microbiology, Ghent University, Ghent 9000, Belgium
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26
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Wu T, Chen W, Yang Z, Tan H, Wang J, Xiao X, Li M, Zhao M. DNA terminal structure-mediated enzymatic reaction for ultra-sensitive discrimination of single nucleotide variations in circulating cell-free DNA. Nucleic Acids Res 2018; 46:e24. [PMID: 29190359 PMCID: PMC5829738 DOI: 10.1093/nar/gkx1218] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Revised: 11/08/2017] [Accepted: 11/23/2017] [Indexed: 12/18/2022] Open
Abstract
Sensitive detection of the single nucleotide variants in cell-free DNA (cfDNA) may provide great opportunity for minimally invasive diagnosis and prognosis of cancer and other related diseases. Here, we demonstrate a facile new strategy for quantitative measurement of cfDNA mutations at low abundance in the cancer patients' plasma samples. The method takes advantage of a novel property of lambda exonuclease which effectively digests a 5'-fluorophore modified dsDNA with a 2-nt overhang structure and sensitively responds to the presence of mismatched base pairs in the duplex. It achieves a limit of detection as low as 0.02% (percentage of the mutant type) for BRAFV600E mutation, NRASQ61R mutation and three types of EGFR mutations (G719S, T790M and L858R). The method enabled identification of BRAFV600E and EGFRL858R mutations in the plasma of different cancer patients within only 3.5 h. Moreover, the terminal structure-dependent reaction greatly simplifies the probe design and reduces the cost, and the assay only requires a regular real-time PCR machine. This new method may serve as a practical tool for quantitative measurement of low-abundance mutations in clinical samples for providing genetic mutation information with prognostic or therapeutic implications.
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Affiliation(s)
- Tongbo Wu
- Beijing National Laboratory for Molecular Sciences and MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Wei Chen
- Beijing National Laboratory for Molecular Sciences and MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Ziyu Yang
- Beijing National Laboratory for Molecular Sciences and MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Haocheng Tan
- Beijing National Laboratory for Molecular Sciences and MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Jiayu Wang
- Beijing National Laboratory for Molecular Sciences and MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Xianjin Xiao
- Family Planning Research Institute/Center of Reproductive Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Mengyuan Li
- Beijing National Laboratory for Molecular Sciences and MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Meiping Zhao
- Beijing National Laboratory for Molecular Sciences and MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
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27
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Kang Z, Ding W, Jin P, Du G, Chen J. DNA Assembly with the DATEL Method. Methods Mol Biol 2018; 1772:421-428. [PMID: 29754243 DOI: 10.1007/978-1-4939-7795-6_24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Simple and reliable DNA assembly methods have become a critical technique in synthetic biology. Here, we present a protocol of the recently developed DATEL (scarless and sequence-independent DNA assembly method using thermostable exonuclease and ligase) method for the construction of genetic circuits and biological pathways from multiple DNA parts in one tube. DATEL is expected to be an applicable choice for both manual and automated high-throughput assembly of DNA fragments, which will greatly facilitate the rapid progress of synthetic biology and metabolic engineering.
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Affiliation(s)
- Zhen Kang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China.
- Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi, Jiangsu, China.
- The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China.
| | - Wenwen Ding
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Peng Jin
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Guocheng Du
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
- Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi, Jiangsu, China
| | - Jian Chen
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
- Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi, Jiangsu, China
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28
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Liu YL, Wu HP, Zhou Q, Song QX, Rui JZ, Guan XX, Zhou GH, Zou BJ. Controllable extension of hairpin-structured flaps to allow low-background cascade invasive reaction for a sensitive DNA logic sensor for mutation detection. Chem Sci 2017; 9:1666-1673. [PMID: 29675214 PMCID: PMC5887964 DOI: 10.1039/c7sc04210h] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 12/14/2017] [Indexed: 01/05/2023] Open
Abstract
A sensitive DNA logic sensor was constructed based on a controllable-extension bridged cascade invasive reaction.
A DNA logic sensor was constructed for gene mutation analysis based on a novel signal amplification cascade by controllably extending a hairpin-structured flap to bridge two invasive reactions. The detection limit was as low as 0.07 fM, and the analytical specificity is high enough to unambiguously pick up 0.02% mutants from a large amount of wild-type DNA. Gene mutations related to the personalized medicine of gefitinib, a typical tyrosine kinase inhibitor, were analyzed by the DNA logic sensor with only a 15 minute response time. Successful assay of tissue samples and cell-free plasma DNA indicates that the new concept we proposed here could benefit clinicians for straightforward prescription of a mutation-targeted drug.
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Affiliation(s)
- Yun-Long Liu
- Department of Pharmacology , Jinling Hospital , Medical School of Nanjing University , Nanjing 210002 , China . ; .,State Key Laboratory of Natural Medicines , Department of Biomedical Engineering , School of Engineering , China Pharmaceutical University , Nanjing 210009 , China
| | - Hai-Ping Wu
- Huadong Research Institute for Medicine and Biotechnics , Nanjing 210002 , China
| | - Qiang Zhou
- Key Laboratory of Drug Quality Control and Pharmacovigilance of Ministry of Education , China Pharmaceutical University , Nanjing 210009 , China
| | - Qin-Xin Song
- Key Laboratory of Drug Quality Control and Pharmacovigilance of Ministry of Education , China Pharmaceutical University , Nanjing 210009 , China
| | - Jian-Zhong Rui
- Department of Pharmacology , Jinling Hospital , Medical School of Nanjing University , Nanjing 210002 , China . ;
| | - Xiao-Xiang Guan
- Department of Pharmacology , Jinling Hospital , Medical School of Nanjing University , Nanjing 210002 , China . ;
| | - Guo-Hua Zhou
- Department of Pharmacology , Jinling Hospital , Medical School of Nanjing University , Nanjing 210002 , China . ;
| | - Bing-Jie Zou
- Department of Pharmacology , Jinling Hospital , Medical School of Nanjing University , Nanjing 210002 , China . ;
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29
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Krzywkowski T, Nilsson M. Fidelity of RNA templated end-joining by chlorella virus DNA ligase and a novel iLock assay with improved direct RNA detection accuracy. Nucleic Acids Res 2017; 45:e161. [PMID: 29048593 PMCID: PMC5737725 DOI: 10.1093/nar/gkx708] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 08/01/2017] [Indexed: 11/29/2022] Open
Abstract
Ligation-based nucleic acid detection methods are primarily limited to DNA, since they exhibit poor performance on RNA. This is attributed to reduced end-joining efficiency and/or fidelity of ligases. Interestingly, chlorella virus DNA ligase (PBCV-1 DNA ligase) has recently been shown to possess high RNA-templated DNA end-joining activity; however, its fidelity has not yet been systematically evaluated. Herein, we characterized PBCV-1 ligase for its RNA-templated end-joining fidelity at single base mismatches in 3′ and 5′ DNA probe termini and found an overall limited end-joining fidelity. To improve the specificity in PBCV-1 ligase-driven RNA detection assays, we utilized structure-specific 5′ exonucleolytic activity of Thermus aquaticus DNA polymerase, used in the invader assay. In the iLock (invader padLock) probe assay, padlock probe molecules are activated prior ligation thus the base at the probe ligation junction is read twice in order to aid successful DNA ligation: first, during structure-specific invader cleavage and then during sequence-specific DNA ligation. We report two distinct iLock probe activation mechanisms and systematically evaluate the assay specificity, including single nucleotide polymorphisms on RNA, mRNA and miRNA. We show significant increase in PBCV-1 ligation fidelity in the iLock probe assay configuration for RNA detection.
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Affiliation(s)
- Tomasz Krzywkowski
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, SE-171 65 Solna, Sweden
| | - Mats Nilsson
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, SE-171 65 Solna, Sweden
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30
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Highly sensitive and specific Alu-based quantification of human cells among rodent cells. Sci Rep 2017; 7:13202. [PMID: 29038571 PMCID: PMC5643497 DOI: 10.1038/s41598-017-13402-3] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 09/22/2017] [Indexed: 01/10/2023] Open
Abstract
Alu elements are primate-specific short interspersed elements (SINEs), over 1 million copies of which are present in the human genome; thus, Alu elements are useful targets for detecting human cells. However, previous Alu-based techniques for detecting human genomic DNA do not reach the theoretical limits of sensitivity and specificity. In this study, we developed a highly sensitive and specific Alu-based real-time PCR method for discriminating human cells from rodent cells, using a primer and probe set carefully designed to avoid possible cross-reactions with rodent genomes. From 100 ng of mixed human and rodent genomes, 1 fg of human genome, equivalent to 1 human cell in 100 million rodent cells, was detectable. Furthermore, in vivo mouse subrenal capsule xenotransplantation assays revealed that 10 human cells per mouse organ were detectable. In addition, after intravenous injection of human mesenchymal stem cells into NOD/SCID mice via tail vein, the biodistribution of human cells was trackable in the mouse lungs and kidneys for at least 1 week. Our findings indicate that our primer and probe set is applicable for the quantitative detection of tiny amounts of human cells, such as xenotransplanted human cancer or stem cells, in rodents.
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31
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Matelska D, Steczkiewicz K, Ginalski K. Comprehensive classification of the PIN domain-like superfamily. Nucleic Acids Res 2017; 45:6995-7020. [PMID: 28575517 PMCID: PMC5499597 DOI: 10.1093/nar/gkx494] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 05/24/2017] [Indexed: 12/21/2022] Open
Abstract
PIN-like domains constitute a widespread superfamily of nucleases, diverse in terms of the reaction mechanism, substrate specificity, biological function and taxonomic distribution. Proteins with PIN-like domains are involved in central cellular processes, such as DNA replication and repair, mRNA degradation, transcription regulation and ncRNA maturation. In this work, we identify and classify the most complete set of PIN-like domains to provide the first comprehensive analysis of sequence–structure–function relationships within the whole PIN domain-like superfamily. Transitive sequence searches using highly sensitive methods for remote homology detection led to the identification of several new families, including representatives of Pfam (DUF1308, DUF4935) and CDD (COG2454), and 23 other families not classified in the public domain databases. Further sequence clustering revealed relationships between individual sequence clusters and showed heterogeneity within some families, suggesting a possible functional divergence. With five structural groups, 70 defined clusters, over 100,000 proteins, and broad biological functions, the PIN domain-like superfamily constitutes one of the largest and most diverse nuclease superfamilies. Detailed analyses of sequences and structures, domain architectures, and genomic contexts allowed us to predict biological function of several new families, including new toxin-antitoxin components, proteins involved in tRNA/rRNA maturation and transcription/translation regulation.
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Affiliation(s)
- Dorota Matelska
- University of Warsaw, CeNT, Laboratory of Bioinformatics and Systems Biology, Zwirki i Wigury 93, 02-089 Warsaw, Poland
| | - Kamil Steczkiewicz
- University of Warsaw, CeNT, Laboratory of Bioinformatics and Systems Biology, Zwirki i Wigury 93, 02-089 Warsaw, Poland
| | - Krzysztof Ginalski
- University of Warsaw, CeNT, Laboratory of Bioinformatics and Systems Biology, Zwirki i Wigury 93, 02-089 Warsaw, Poland
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32
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The DNA Repair Repertoire of Mycobacterium smegmatis FenA Includes the Incision of DNA 5' Flaps and the Removal of 5' Adenylylated Products of Aborted Nick Ligation. J Bacteriol 2017. [PMID: 28630124 DOI: 10.1128/jb.00304-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
We characterize Mycobacterium smegmatis FenA as a manganese-dependent 5'-flap endonuclease homologous to the 5'-exonuclease of DNA polymerase I. FenA incises a nicked 5' flap between the first and second nucleotides of the duplex segment to yield a 1-nucleotide gapped DNA, which is then further resected in dinucleotide steps. Initial FenA cleavage at a Y-flap or nick occurs between the first and second nucleotides of the duplex. However, when the template 3' single strand is eliminated to create a 5'-tailed duplex, FenA incision shifts to between the second and third nucleotides. A double-flap substrate with a mobile junction (mimicking limited strand displacement synthesis during gap repair) is preferentially incised as the 1-nucleotide 3'-flap isomer, with the scissile phosphodiester shifted by one nucleotide versus a static double flap. FenA efficiently removes the 5' App(dN) terminus of an aborted nick ligation reaction intermediate, thereby highlighting FenA as an agent of repair of such lesions, which are formed under a variety of circumstances by bacterial NAD+-dependent DNA ligases and especially by mycobacterial DNA ligases D and C.IMPORTANCE Structure-specific DNA endonucleases are implicated in bacterial DNA replication, repair, and recombination, yet there is scant knowledge of the roster and catalytic repertoire of such nucleases in Mycobacteria This study identifies M. smegmatis FenA as a stand-alone endonuclease homologous to the 5'-exonuclease domain of mycobacterial DNA polymerase 1. FenA incises 5' flaps, 5' nicks, and 5' App(dN) intermediates of aborted nick ligation. The isolated N-terminal domain of M. smegmatis Pol1 is also shown to be a flap endonuclease.
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33
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Senissar M, Manav MC, Brodersen DE. Structural conservation of the PIN domain active site across all domains of life. Protein Sci 2017; 26:1474-1492. [PMID: 28508407 DOI: 10.1002/pro.3193] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 05/08/2017] [Accepted: 05/08/2017] [Indexed: 01/26/2023]
Abstract
The PIN (PilT N-terminus) domain is a compact RNA-binding protein domain present in all domains of life. This 120-residue domain consists of a central and parallel β sheet surrounded by α helices, which together organize 4-5 acidic residues in an active site that binds one or more divalent metal ions and in many cases has endoribonuclease activity. In bacteria and archaea, the PIN domain is primarily associated with toxin-antitoxin loci, consisting of a toxin (the PIN domain nuclease) and an antitoxin that inhibits the function of the toxin under normal growth conditions. During nutritional or antibiotic stress, the antitoxin is proteolytically degraded causing activation of the PIN domain toxin leading to a dramatic reprogramming of cellular metabolism to cope with the new situation. In eukaryotes, PIN domains are commonly found as parts of larger proteins and are involved in a range of processes involving RNA cleavage, including ribosomal RNA biogenesis and nonsense-mediated mRNA decay. In this review, we provide a comprehensive overview of the structural characteristics of the PIN domain and compare PIN domains from all domains of life in terms of structure, active site architecture, and activity.
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Affiliation(s)
- M Senissar
- Centre for Bacterial Stress Response and Persistence, Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10c, Aarhus, 8000, Denmark
| | - M C Manav
- Centre for Bacterial Stress Response and Persistence, Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10c, Aarhus, 8000, Denmark
| | - D E Brodersen
- Centre for Bacterial Stress Response and Persistence, Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10c, Aarhus, 8000, Denmark
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34
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Dehé PM, Gaillard PHL. Control of structure-specific endonucleases to maintain genome stability. Nat Rev Mol Cell Biol 2017; 18:315-330. [PMID: 28327556 DOI: 10.1038/nrm.2016.177] [Citation(s) in RCA: 116] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Structure-specific endonucleases (SSEs) have key roles in DNA replication, recombination and repair, and emerging roles in transcription. These enzymes have specificity for DNA secondary structure rather than for sequence, and therefore their activity must be precisely controlled to ensure genome stability. In this Review, we discuss how SSEs are controlled as part of genome maintenance pathways in eukaryotes, with an emphasis on the elaborate mechanisms that regulate the members of the major SSE families - including the xeroderma pigmentosum group F-complementing protein (XPF) and MMS and UV-sensitive protein 81 (MUS81)-dependent nucleases, and the flap endonuclease 1 (FEN1), XPG and XPG-like endonuclease 1 (GEN1) enzymes - during processes such as DNA adduct repair, Holliday junction processing and replication stress. We also discuss newly characterized connections between SSEs and other classes of DNA-remodelling enzymes and cell cycle control machineries, which reveal the importance of SSE scaffolds such as the synthetic lethal of unknown function 4 (SLX4) tumour suppressor for the maintenance of genome stability.
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Affiliation(s)
- Pierre-Marie Dehé
- Centre de Recherche en Cancérologie de Marseille, CRCM, CNRS, Aix Marseille Université, INSERM, Institut Paoli-Calmettes, 27 Boulevard Leï Roure, 13009 Marseille, France
| | - Pierre-Henri L Gaillard
- Centre de Recherche en Cancérologie de Marseille, CRCM, CNRS, Aix Marseille Université, INSERM, Institut Paoli-Calmettes, 27 Boulevard Leï Roure, 13009 Marseille, France
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35
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Substitutions of short heterologous DNA segments of intragenomic or extragenomic origins produce clustered genomic polymorphisms. Proc Natl Acad Sci U S A 2016; 113:15066-15071. [PMID: 27956618 DOI: 10.1073/pnas.1615819114] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
In a screen for unexplained mutation events we identified a previously unrecognized mechanism generating clustered DNA polymorphisms such as microindels and cumulative SNPs. The mechanism, short-patch double illegitimate recombination (SPDIR), facilitates short single-stranded DNA molecules to invade and replace genomic DNA through two joint illegitimate recombination events. SPDIR is controlled by key components of the cellular genome maintenance machinery in the gram-negative bacterium Acinetobacter baylyi. The source DNA is primarily intragenomic but can also be acquired through horizontal gene transfer. The DNA replacements are nonreciprocal and locus independent. Bioinformatic approaches reveal occurrence of SPDIR events in the gram-positive human pathogen Streptococcus pneumoniae and in the human genome.
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Jin P, Ding W, Du G, Chen J, Kang Z. DATEL: A Scarless and Sequence-Independent DNA Assembly Method Using Thermostable Exonucleases and Ligase. ACS Synth Biol 2016; 5:1028-32. [PMID: 27230689 DOI: 10.1021/acssynbio.6b00078] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
DNA assembly is a pivotal technique in synthetic biology. Here, we report a scarless and sequence-independent DNA assembly method using thermal exonucleases (Taq and Pfu DNA polymerases) and Taq DNA ligase (DATEL). Under the optimized conditions, DATEL allows rapid assembly of 2-10 DNA fragments (1-2 h) with high accuracy (between 74 and 100%). Owing to the simple operation system with denaturation-annealing-cleavage-ligation temperature cycles in one tube, DATEL is expected to be a desirable choice for both manual and automated high-throughput assembly of DNA fragments, which will greatly facilitate the rapid progress of synthetic biology and metabolic engineering.
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Affiliation(s)
- Peng Jin
- The
Key Laboratory of Industrial Biotechnology, Ministry of Education,
School of Biotechnology, ‡The Key Laboratory of Carbohydrate Chemistry and
Biotechnology, Ministry of Education, and §Synergetic Innovation Center of Food
Safety and Nutrition, Jiangnan University, Wuxi 214122, P. R. China
| | - Wenwen Ding
- The
Key Laboratory of Industrial Biotechnology, Ministry of Education,
School of Biotechnology, ‡The Key Laboratory of Carbohydrate Chemistry and
Biotechnology, Ministry of Education, and §Synergetic Innovation Center of Food
Safety and Nutrition, Jiangnan University, Wuxi 214122, P. R. China
| | - Guocheng Du
- The
Key Laboratory of Industrial Biotechnology, Ministry of Education,
School of Biotechnology, ‡The Key Laboratory of Carbohydrate Chemistry and
Biotechnology, Ministry of Education, and §Synergetic Innovation Center of Food
Safety and Nutrition, Jiangnan University, Wuxi 214122, P. R. China
| | - Jian Chen
- The
Key Laboratory of Industrial Biotechnology, Ministry of Education,
School of Biotechnology, ‡The Key Laboratory of Carbohydrate Chemistry and
Biotechnology, Ministry of Education, and §Synergetic Innovation Center of Food
Safety and Nutrition, Jiangnan University, Wuxi 214122, P. R. China
| | - Zhen Kang
- The
Key Laboratory of Industrial Biotechnology, Ministry of Education,
School of Biotechnology, ‡The Key Laboratory of Carbohydrate Chemistry and
Biotechnology, Ministry of Education, and §Synergetic Innovation Center of Food
Safety and Nutrition, Jiangnan University, Wuxi 214122, P. R. China
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Direct observation of DNA threading in flap endonuclease complexes. Nat Struct Mol Biol 2016; 23:640-6. [PMID: 27273516 PMCID: PMC4939078 DOI: 10.1038/nsmb.3241] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Accepted: 05/10/2016] [Indexed: 02/06/2023]
Abstract
Maintenance of genome integrity requires that branched nucleic acid
molecules are accurately processed to produce double-helical DNA. Flap
endonucleases are essential enzymes that trim such branched molecules generated
by Okazaki fragment synthesis during replication. Here, we report crystal
structures of bacteriophage T5 flap endonuclease in complexes with intact DNA
substrates, and products, at resolutions of 1.9–2.2 Å. They reveal
single-stranded DNA threading through a hole in the enzyme enclosed by an
inverted V-shaped helical arch straddling the active site. Residues lining the
hole induce an unusual barb-like conformation in the DNA substrate juxtaposing
the scissile phosphate and essential catalytic metal ions. A series of complexes
and biochemical analyses show how the substrate’s single-stranded branch
approaches, threads through, and finally emerges on the far side of the enzyme.
Our studies suggest that substrate recognition involves an unusual
“fly-casting, thread, bend and barb” mechanism.
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Wadle S, Lehnert M, Rubenwolf S, Zengerle R, von Stetten F. Real-time PCR probe optimization using design of experiments approach. BIOMOLECULAR DETECTION AND QUANTIFICATION 2016; 7:1-8. [PMID: 27077046 PMCID: PMC4827641 DOI: 10.1016/j.bdq.2015.12.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 12/16/2015] [Accepted: 12/16/2015] [Indexed: 12/28/2022]
Abstract
Primer and probe sequence designs are among the most critical input factors in real-time polymerase chain reaction (PCR) assay optimization. In this study, we present the use of statistical design of experiments (DOE) approach as a general guideline for probe optimization and more specifically focus on design optimization of label-free hydrolysis probes that are designated as mediator probes (MPs), which are used in reverse transcription MP PCR (RT-MP PCR). The effect of three input factors on assay performance was investigated: distance between primer and mediator probe cleavage site; dimer stability of MP and target sequence (influenza B virus); and dimer stability of the mediator and universal reporter (UR). The results indicated that the latter dimer stability had the greatest influence on assay performance, with RT-MP PCR efficiency increased by up to 10% with changes to this input factor. With an optimal design configuration, a detection limit of 3-14 target copies/10 μl reaction could be achieved. This improved detection limit was confirmed for another UR design and for a second target sequence, human metapneumovirus, with 7-11 copies/10 μl reaction detected in an optimum case. The DOE approach for improving oligonucleotide designs for real-time PCR not only produces excellent results but may also reduce the number of experiments that need to be performed, thus reducing costs and experimental times.
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Affiliation(s)
- S. Wadle
- Laboratory for MEMS Applications, IMTEK—Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany
- Hahn-Schickard Institut für Mikro-und Informationstechnik, Georges-Koehler-Allee 103, 79110 Freiburg, Germany
| | - M. Lehnert
- Laboratory for MEMS Applications, IMTEK—Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany
| | - S. Rubenwolf
- Laboratory for MEMS Applications, IMTEK—Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany
| | - R. Zengerle
- Laboratory for MEMS Applications, IMTEK—Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany
- Hahn-Schickard Institut für Mikro-und Informationstechnik, Georges-Koehler-Allee 103, 79110 Freiburg, Germany
- BIOSS—Centre for Biological Signalling Studies, University of Freiburg, 79110 Freiburg, Germany
| | - F. von Stetten
- Laboratory for MEMS Applications, IMTEK—Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany
- Hahn-Schickard Institut für Mikro-und Informationstechnik, Georges-Koehler-Allee 103, 79110 Freiburg, Germany
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39
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Abstract
DNA exonucleases, enzymes that hydrolyze phosphodiester bonds in DNA from a free end, play important cellular roles in DNA repair, genetic recombination and mutation avoidance in all organisms. This article reviews the structure, biochemistry, and biological functions of the 17 exonucleases currently identified in the bacterium Escherichia coli. These include the exonucleases associated with DNA polymerases I (polA), II (polB), and III (dnaQ/mutD); Exonucleases I (xonA/sbcB), III (xthA), IV, VII (xseAB), IX (xni/xgdG), and X (exoX); the RecBCD, RecJ, and RecE exonucleases; SbcCD endo/exonucleases; the DNA exonuclease activities of RNase T (rnt) and Endonuclease IV (nfo); and TatD. These enzymes are diverse in terms of substrate specificity and biochemical properties and have specialized biological roles. Most of these enzymes fall into structural families with characteristic sequence motifs, and members of many of these families can be found in all domains of life.
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40
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Yeom T, Lee J, Lee S, Kang S, Kim KR, Han B, Lee HS, Jo K. Mass spectrometric investigation of the role of the linking polypeptide chain in DNA polymerase I. Analyst 2015; 139:2432-9. [PMID: 24695614 DOI: 10.1039/c4an00107a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
DNA polymerase I offers great promise for a wide range of biotechnological applications due to its capability to add labeled nucleotides into double-stranded large DNA molecules by using both polymerase and nuclease domains. Accordingly, it is crucially important to thoroughly characterize this enzyme for further developments. Although the enzyme has been thus far characterized using mainly traditional analytical instruments, here we utilized an advanced and convenient means of mass spectrometry to elucidate enzymatic functions and mechanisms by measuring DNA oligomers generated by polymerase and nuclease reactions. Our analysis revealed several novel enzymatic features, including the observation that polymerase readily dissociates from the DNA molecules containing a wide single-stranded section. From this finding, we reasoned a serious situation of DNA break because polymerase domains cannot efficiently repair the wide single-stranded section, which is susceptible to DNA breaks. Furthermore, we deduced a plausible explanation for a paradoxical question as to why two domains of polymerase and 5'-nuclease are linked by a small and flexible polypeptide in polymerase I. The polypeptide link seems to prevent a 5'-nuclease from causing DNA breaks by locating a polymerase domain closely for immediate repair reaction. Here we present experimental evidence to prove our hypothesis via a set of mass spectrometric analyses as well as single DNA molecule observation and bacterial cell growth assay. Consequently, mass spectrometric analysis for DNA polymerase I provides a meaningful biological insight that a polypeptide link can be a molecular leash to control an aggressive domain in order to prevent unmanageable damages.
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Affiliation(s)
- Taeho Yeom
- Department of Chemistry and Interdisciplinary Program of Integrated Biotechnology, Sogang University, Seoul, 121-742, Republic of Korea.
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Anwaruzzaman M, Wang W, Wang E, Erfe L, Lee J, Liu S. Evaluation of infectivity and reverse transcriptase real-time polymerase chain reaction assays for detection of xenotropic murine leukemia virus used in virus clearance validation. Biologicals 2015; 43:256-65. [PMID: 25997567 DOI: 10.1016/j.biologicals.2015.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 01/17/2015] [Accepted: 04/05/2015] [Indexed: 11/18/2022] Open
Abstract
Infectivity and reverse transcriptase quantitative real-time polymerase chain reaction (qRT-PCR) assays have been optimized and validated for xenotropic murine leukemia virus (X-MuLV) detection. We have evaluated the assays systematically with regard to specificity, linearity, lower limit of detection (LLOD), lower limit of quantification (LLOQ), and precision. Both assays are specific for X-MuLV detection, with a linear detection range of 0.6-5.6 log(10) TCID(50)/mL for the infectivity assay, and 1.4-6.5 log(10) particles/mL for the qRT-PCR assay. The LLOD and LLOQ of the infectivity and the qRT-PCR assays are determined as 0.5 and 1.0 log(10)/mL, and 1.4 and 2.2 log(10)/mL. The inter-assay repeatability of qRT-PCR assay (4.2% coefficient of variation [CV]) is higher than the infectivity assay (7.9% CV). We have shown that both assays are closely correlated (r = 0.85, P < 0.05, n = 22). The particle/infectivity ratio is determined as 66. Both assays were applied to evaluate virus removal using virus clearance samples of chromatographic and filtration processes. Here, we have demonstrated that the qRT-PCR assay is much faster in testing and is approximately 8-fold more sensitive than the infectivity assay. Therefore, the qRT-PCR assay can replace the infectivity assay in many cases, but both assays are complementary in elucidating the mechanism of virus inactivation and removal in virus clearance validation.
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Affiliation(s)
- Mohammad Anwaruzzaman
- Pathogen Safety Department, Global Biologics Development, Bayer HealthCare Pharmaceuticals, Berkeley, CA, USA
| | - Wensheng Wang
- Pathogen Safety Department, Global Biologics Development, Bayer HealthCare Pharmaceuticals, Berkeley, CA, USA
| | - Eunice Wang
- Pathogen Safety Department, Global Biologics Development, Bayer HealthCare Pharmaceuticals, Berkeley, CA, USA
| | - Lolita Erfe
- Pathogen Safety Department, Global Biologics Development, Bayer HealthCare Pharmaceuticals, Berkeley, CA, USA
| | - Janice Lee
- Pathogen Safety Department, Global Biologics Development, Bayer HealthCare Pharmaceuticals, Berkeley, CA, USA
| | - Shengjiang Liu
- Pathogen Safety Department, Global Biologics Development, Bayer HealthCare Pharmaceuticals, Berkeley, CA, USA.
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42
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Wu T, Xiao X, Gu F, Zhao M. Sensitive discrimination of stable mismatched base pairs by an abasic site modified fluorescent probe and lambda exonuclease. Chem Commun (Camb) 2015; 51:17402-5. [DOI: 10.1039/c5cc05749c] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
An abasic site modified fluorescent probe has been developed which enabled the rapid discrimination of stable single mismatched base pairs by lambda exonuclease with remarkably high discrimination factors (447 for T:G and 238 for A:G).
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Affiliation(s)
- Tongbo Wu
- Beijing National Laboratory for Molecular Sciences
- MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering
- College of Chemistry and Molecular Engineering
- Peking University
- Beijing, 100871
| | - Xianjin Xiao
- Beijing National Laboratory for Molecular Sciences
- MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering
- College of Chemistry and Molecular Engineering
- Peking University
- Beijing, 100871
| | - Feidan Gu
- Beijing National Laboratory for Molecular Sciences
- MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering
- College of Chemistry and Molecular Engineering
- Peking University
- Beijing, 100871
| | - Meiping Zhao
- Beijing National Laboratory for Molecular Sciences
- MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering
- College of Chemistry and Molecular Engineering
- Peking University
- Beijing, 100871
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43
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Kalle E, Kubista M, Rensing C. Multi-template polymerase chain reaction. BIOMOLECULAR DETECTION AND QUANTIFICATION 2014; 2:11-29. [PMID: 27896140 PMCID: PMC5121205 DOI: 10.1016/j.bdq.2014.11.002] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 11/25/2014] [Accepted: 11/26/2014] [Indexed: 12/12/2022]
Abstract
PCR is a formidable and potent technology that serves as an indispensable tool in a wide range of biological disciplines. However, due to the ease of use and often lack of rigorous standards many PCR applications can lead to highly variable, inaccurate, and ultimately meaningless results. Thus, rigorous method validation must precede its broad adoption to any new application. Multi-template samples possess particular features, which make their PCR analysis prone to artifacts and biases: multiple homologous templates present in copy numbers that vary within several orders of magnitude. Such conditions are a breeding ground for chimeras and heteroduplexes. Differences in template amplification efficiencies and template competition for reaction compounds undermine correct preservation of the original template ratio. In addition, the presence of inhibitors aggravates all of the above-mentioned problems. Inhibitors might also have ambivalent effects on the different templates within the same sample. Yet, no standard approaches exist for monitoring inhibitory effects in multitemplate PCR, which is crucial for establishing compatibility between samples.
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Affiliation(s)
- Elena Kalle
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Allmas alle 5, 75007 Uppsala, Sweden
| | - Mikael Kubista
- TATAA Biocenter, Odinsgatan 28, 41103 Göteborg, Sweden; Institute of Biotechnology, Czech Academy of Sciences
| | - Christopher Rensing
- Department of Plant and Environmental Sciences, Faculty of Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark
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44
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Garrett M, Poland B, Brennan M, Hee B, Pithavala YK, Amantea MA. Population pharmacokinetic analysis of axitinib in healthy volunteers. Br J Clin Pharmacol 2014; 77:480-92. [PMID: 23834452 DOI: 10.1111/bcp.12206] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 06/18/2013] [Indexed: 11/29/2022] Open
Abstract
AIMS Axitinib is a potent and selective second generation inhibitor of vascular endothelial growth factor receptors 1, 2 and 3 approved for second line treatment of advanced renal cell carcinoma. The objectives of this analysis were to assess plasma pharmacokinetics and identify covariates that may explain variability in axitinib disposition following single dose administration in healthy volunteers. METHODS Plasma concentration-time data from 337 healthy volunteers in 10 phase I studies were analyzed, using non-linear mixed effects modelling (nonmem) to estimate population pharmacokinetic parameters and evaluate relationships between parameters and food, formulation, demographic factors, measures of renal and hepatic function and metabolic genotypes (UGT1A1*28 and CYP2C19). RESULTS A two compartment structural model with first order absorption and lag time best described axitinib pharmacokinetics. Population estimates for systemic clearance (CL), central volume of distribution (Vc ), absorption rate constant (ka ) and absolute bioavailability (F) were 17.0 l h(-1) , 45.3 l, 0.523 h(-1) and 46.5%, respectively. With axitinib Form IV, ka and F increased in the fasted state by 207% and 33.8%, respectively. For Form XLI (marketed formulation), F was 15% lower compared with Form IV. CL was not significantly influenced by any of the covariates studied. Body weight significantly affected Vc , but the effect was within the estimated interindividual variability for Vc . CONCLUSIONS The analysis established a model that adequately characterizes axitinib pharmacokinetics in healthy volunteers. Vc was found to increase with body weight. However, no change in plasma exposures is expected with change in body weight; hence no dose adjustment is warranted.
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Affiliation(s)
- May Garrett
- Pfizer Global Pharmacometrics, San Diego, CA, USA
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45
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Fricker AD, Peters JE. Vulnerabilities on the lagging-strand template: opportunities for mobile elements. Annu Rev Genet 2014; 48:167-86. [PMID: 25195506 DOI: 10.1146/annurev-genet-120213-092046] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Mobile genetic elements have the ability to move between positions in a genome. Some of these elements are capable of targeting one of the template strands during DNA replication. Examples found in bacteria include (a) Red recombination mediated by bacteriophage λ, (b) integration of group II mobile introns that reverse splice and reverse transcribe into DNA, (c) HUH endonuclease elements that move as single-stranded DNA, and (d) Tn7, a DNA cut-and-paste transposon that uses a target-site-selecting protein to target transposition into certain forms of DNA replication. In all of these examples, the lagging-strand template appears to be targeted using a variety of features specific to this strand. These features appear especially available in certain situations, such as when replication forks stall or collapse. In this review, we address the idea that features specific to the lagging-strand template represent vulnerabilities that are capitalized on by mobile genetic elements.
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Affiliation(s)
- Ashwana D Fricker
- Department of Microbiology, Cornell University, Ithaca, New York 14853;
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46
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Zhao G, Tang S, Li J, Hu T, Guan Y. Effects of cations on small fragment of DNA polymerase I using a novel FRET assay. Acta Biochim Biophys Sin (Shanghai) 2014; 46:659-67. [PMID: 24966186 DOI: 10.1093/abbs/gmu050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
DNA polymerase I (PolI) digested by protease produces a small fragment (SF) containing 5'-3' exonuclease activity. The 5'-3' exonuclease activity of polI cleaves the downstream RNA primer strands during DNA replication in vivo. Previous in vitro studies suggested its capability of cleaving duplex from 5' terminal and a flap-structure-specific endonuclease activity. From the crystal structures of other nucleases and biochemical data, a two-metal-ion mechanism has been proposed but has not been determined. In this study, we cloned, expressed, and purified the SF protein, and established a novel fluorescence resonance energy transfer (FRET) assay to analyze the catalytic activity of the SF protein. The effects of several metal ions on its catalytic capability were analyzed using this FRET assay. Results showed that Mg2+, Mn2+, and Zn2+ were able to activate the cleavage of SF, while Ca2+, Ni2 +, and Co2+ were not suitable for SF catalysis. The effects of K+, Na+, and dNTP were also determined.
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47
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Xu C, Maxwell BA, Suo Z. Conformational dynamics of Thermus aquaticus DNA polymerase I during catalysis. J Mol Biol 2014; 426:2901-2917. [PMID: 24931550 DOI: 10.1016/j.jmb.2014.06.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 06/02/2014] [Accepted: 06/07/2014] [Indexed: 11/15/2022]
Abstract
Despite the fact that DNA polymerases have been investigated for many years and are commonly used as tools in a number of molecular biology assays, many details of the kinetic mechanism they use to catalyze DNA synthesis remain unclear. Structural and kinetic studies have characterized a rapid, pre-catalytic open-to-close conformational change of the Finger domain during nucleotide binding for many DNA polymerases including Thermus aquaticus DNA polymerase I (Taq Pol), a thermostable enzyme commonly used for DNA amplification in PCR. However, little has been performed to characterize the motions of other structural domains of Taq Pol or any other DNA polymerase during catalysis. Here, we used stopped-flow Förster resonance energy transfer to investigate the conformational dynamics of all five structural domains of the full-length Taq Pol relative to the DNA substrate during nucleotide binding and incorporation. Our study provides evidence for a rapid conformational change step induced by dNTP binding and a subsequent global conformational transition involving all domains of Taq Pol during catalysis. Additionally, our study shows that the rate of the global transition was greatly increased with the truncated form of Taq Pol lacking the N-terminal domain. Finally, we utilized a mutant of Taq Pol containing a de novo disulfide bond to demonstrate that limiting protein conformational flexibility greatly reduced the polymerization activity of Taq Pol.
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Affiliation(s)
- Cuiling Xu
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Brian A Maxwell
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA.,Ohio State Biophysics Program, The Ohio State University, Columbus, OH 43210, USA
| | - Zucai Suo
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA.,Ohio State Biophysics Program, The Ohio State University, Columbus, OH 43210, USA
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48
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Vaisman A, McDonald JP, Noll S, Huston D, Loeb G, Goodman MF, Woodgate R. Investigating the mechanisms of ribonucleotide excision repair in Escherichia coli. Mutat Res 2014; 761:21-33. [PMID: 24495324 DOI: 10.1016/j.mrfmmm.2014.01.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 12/21/2013] [Accepted: 01/23/2014] [Indexed: 01/01/2023]
Abstract
Low fidelity Escherichia coli DNA polymerase V (pol V/UmuD'2C) is best characterized for its ability to perform translesion synthesis (TLS). However, in recA730 lexA(Def) strains, the enzyme is expressed under optimal conditions allowing it to compete with the cell's replicase for access to undamaged chromosomal DNA and leads to a substantial increase in spontaneous mutagenesis. We have recently shown that a Y11A substitution in the "steric gate" residue of UmuC reduces both base and sugar selectivity of pol V, but instead of generating an increased number of spontaneous mutations, strains expressing umuC_Y11A are poorly mutable in vivo. This phenotype is attributed to efficient RNase HII-initiated repair of the misincorporated ribonucleotides that concomitantly removes adjacent misincorporated deoxyribonucleotides. We have utilized the ability of the pol V steric gate mutant to promote incorporation of large numbers of errant ribonucleotides into the E. coli genome to investigate the fundamental mechanisms underlying ribonucleotide excision repair (RER). Here, we demonstrate that RER is normally facilitated by DNA polymerase I (pol I) via classical "nick translation". In vitro, pol I displaces 1-3 nucleotides of the RNA/DNA hybrid and through its 5'→3' (exo/endo) nuclease activity releases ribo- and deoxyribonucleotides from DNA. In vivo, umuC_Y11A-dependent mutagenesis changes significantly in polymerase-deficient, or proofreading-deficient polA strains, indicating a pivotal role for pol I in ribonucleotide excision repair (RER). However, there is also considerable redundancy in the RER pathway in E. coli. Pol I's strand displacement and FLAP-exo/endonuclease activities can be facilitated by alternate enzymes, while the DNA polymerization step can be assumed by high-fidelity pol III. We conclude that RNase HII and pol I normally act to minimize the genomic instability that is generated through errant ribonucleotide incorporation, but that the "nick-translation" activities encoded by the single pol I polypeptide can be undertaken by a variety of back-up enzymes.
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Affiliation(s)
- Alexandra Vaisman
- Laboratory of Genomic Integrity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-3371, USA
| | - John P McDonald
- Laboratory of Genomic Integrity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-3371, USA
| | - Stephan Noll
- Gene Bridges GmbH, Im Neuenheimer Feld 584, 69120 Heidelberg, Germany
| | - Donald Huston
- Laboratory of Genomic Integrity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-3371, USA
| | - Gregory Loeb
- Laboratory of Genomic Integrity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-3371, USA
| | - Myron F Goodman
- Department of Biological Sciences and Chemistry, University of Southern California, University Park, Los Angeles, CA 90089-2910, USA
| | - Roger Woodgate
- Laboratory of Genomic Integrity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-3371, USA.
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49
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Mitsunobu H, Zhu B, Lee SJ, Tabor S, Richardson CC. Flap endonuclease activity of gene 6 exonuclease of bacteriophage T7. J Biol Chem 2014; 289:5860-75. [PMID: 24394415 DOI: 10.1074/jbc.m113.538611] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Flap endonucleases remove flap structures generated during DNA replication. Gene 6 protein of bacteriophage T7 is a 5'-3'-exonuclease specific for dsDNA. Here we show that gene 6 protein also possesses a structure-specific endonuclease activity similar to known flap endonucleases. The flap endonuclease activity is less active relative to its exonuclease activity. The major cleavage by the endonuclease activity occurs at a position one nucleotide into the duplex region adjacent to a dsDNA-ssDNA junction. The efficiency of cleavage of the flap decreases with increasing length of the 5'-overhang. A 3'-single-stranded tail arising from the same end of the duplex as the 5'-tail inhibits gene 6 protein flap endonuclease activity. The released flap is not degraded further, but the exonuclease activity then proceeds to hydrolyze the 5'-terminal strand of the duplex. T7 gene 2.5 single-stranded DNA-binding protein stimulates the exonuclease and also the endonuclease activity. This stimulation is attributed to a specific interaction between the two proteins because Escherichia coli single-stranded DNA binding protein does not produce this stimulatory effect. The ability of gene 6 protein to remove 5'-terminal overhangs as well as to remove nucleotides from the 5'-termini enables it to effectively process the 5'-termini of Okazaki fragments before they are ligated.
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Affiliation(s)
- Hitoshi Mitsunobu
- From the Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115
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Tambouret R. Female genital tract. Cancer Treat Res 2014; 160:241-272. [PMID: 24092373 DOI: 10.1007/978-3-642-38850-7_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Affiliation(s)
- Rosemary Tambouret
- Department of Pathology, Massachusetts General Hospital, Warren 105/55 Fruit Street, Boston, MA, 02114, USA,
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