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Pathira Kankanamge L, Mora A, Ondrechen MJ, Beuning PJ. Biochemical Activity of 17 Cancer-Associated Variants of DNA Polymerase Kappa Predicted by Electrostatic Properties. Chem Res Toxicol 2023; 36:1789-1803. [PMID: 37883788 PMCID: PMC10664756 DOI: 10.1021/acs.chemrestox.3c00233] [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: 08/06/2023] [Revised: 10/03/2023] [Accepted: 10/04/2023] [Indexed: 10/28/2023]
Abstract
DNA damage and repair have been widely studied in relation to cancer and therapeutics. Y-family DNA polymerases can bypass DNA lesions, which may result from external or internal DNA damaging agents, including some chemotherapy agents. Overexpression of the Y-family polymerase human pol kappa can result in tumorigenesis and drug resistance in cancer. This report describes the use of computational tools to predict the effects of single nucleotide polymorphism variants on pol kappa activity. Partial Order Optimum Likelihood (POOL), a machine learning method that uses input features from Theoretical Microscopic Titration Curve Shapes (THEMATICS), was used to identify amino acid residues most likely involved in catalytic activity. The μ4 value, a metric obtained from POOL and THEMATICS that serves as a measure of the degree of coupling between one ionizable amino acid and its neighbors, was then used to identify which protein mutations are likely to impact the biochemical activity. Bioinformatic tools SIFT, PolyPhen-2, and FATHMM predicted most of these variants to be deleterious to function. Along with computational and bioinformatic predictions, we characterized the catalytic activity and stability of 17 cancer-associated DNA pol kappa variants. We identified pol kappa variants R48I, H105Y, G147D, G154E, V177L, R298C, E362V, and R470C as having lower activity relative to wild-type pol kappa; the pol kappa variants T102A, H142Y, R175Q, E210K, Y221C, N330D, N338S, K353T, and L383F were identified as being similar in catalytic efficiency to WT pol kappa. We observed that POOL predictions can be used to predict which variants have decreased activity. Predictions from bioinformatic tools like SIFT, PolyPhen-2, and FATHMM are based on sequence comparisons and therefore are complementary to POOL but are less capable of predicting biochemical activity. These bioinformatic and computational tools can be used to identify SNP variants with deleterious effects and altered biochemical activity from a large data set.
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Affiliation(s)
- Lakindu
S. Pathira Kankanamge
- Department
of Chemistry and Chemical Biology and Department of Bioengineering, Northeastern University, Boston, Massachusetts 02115, United States
| | - Alexandra Mora
- Department
of Chemistry and Chemical Biology and Department of Bioengineering, Northeastern University, Boston, Massachusetts 02115, United States
| | - Mary Jo Ondrechen
- Department
of Chemistry and Chemical Biology and Department of Bioengineering, Northeastern University, Boston, Massachusetts 02115, United States
| | - Penny J. Beuning
- Department
of Chemistry and Chemical Biology and Department of Bioengineering, Northeastern University, Boston, Massachusetts 02115, United States
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2
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James EI, Murphree TA, Vorauer C, Engen JR, Guttman M. Advances in Hydrogen/Deuterium Exchange Mass Spectrometry and the Pursuit of Challenging Biological Systems. Chem Rev 2021; 122:7562-7623. [PMID: 34493042 PMCID: PMC9053315 DOI: 10.1021/acs.chemrev.1c00279] [Citation(s) in RCA: 95] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
![]()
Solution-phase hydrogen/deuterium
exchange (HDX) coupled to mass
spectrometry (MS) is a widespread tool for structural analysis across
academia and the biopharmaceutical industry. By monitoring the exchangeability
of backbone amide protons, HDX-MS can reveal information about higher-order
structure and dynamics throughout a protein, can track protein folding
pathways, map interaction sites, and assess conformational states
of protein samples. The combination of the versatility of the hydrogen/deuterium
exchange reaction with the sensitivity of mass spectrometry has enabled
the study of extremely challenging protein systems, some of which
cannot be suitably studied using other techniques. Improvements over
the past three decades have continually increased throughput, robustness,
and expanded the limits of what is feasible for HDX-MS investigations.
To provide an overview for researchers seeking to utilize and derive
the most from HDX-MS for protein structural analysis, we summarize
the fundamental principles, basic methodology, strengths and weaknesses,
and the established applications of HDX-MS while highlighting new
developments and applications.
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Affiliation(s)
- Ellie I James
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Taylor A Murphree
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Clint Vorauer
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - John R Engen
- Department of Chemistry & Chemical Biology, Northeastern University, Boston, Massachusetts 02115, United States
| | - Miklos Guttman
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195, United States
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3
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Zhou ZX, Williams JS, Lujan SA, Kunkel TA. Ribonucleotide incorporation into DNA during DNA replication and its consequences. Crit Rev Biochem Mol Biol 2021; 56:109-124. [PMID: 33461360 DOI: 10.1080/10409238.2020.1869175] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Ribonucleotides are the most abundant non-canonical nucleotides in the genome. Their vast presence and influence over genome biology is becoming increasingly appreciated. Here we review the recent progress made in understanding their genomic presence, incorporation characteristics and usefulness as biomarkers for polymerase enzymology. We also discuss ribonucleotide processing, the genetic consequences of unrepaired ribonucleotides in DNA and evidence supporting the significance of their transient presence in the nuclear genome.
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Affiliation(s)
- Zhi-Xiong Zhou
- Genome Integrity & Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, DHHS, Durham, NC, USA
| | - Jessica S Williams
- Genome Integrity & Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, DHHS, Durham, NC, USA
| | - Scott A Lujan
- Genome Integrity & Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, DHHS, Durham, NC, USA
| | - Thomas A Kunkel
- Genome Integrity & Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, DHHS, Durham, NC, USA
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Johnson MK, Kottur J, Nair DT. A polar filter in DNA polymerases prevents ribonucleotide incorporation. Nucleic Acids Res 2020; 47:10693-10705. [PMID: 31544946 PMCID: PMC6846668 DOI: 10.1093/nar/gkz792] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 09/02/2019] [Accepted: 09/09/2019] [Indexed: 12/17/2022] Open
Abstract
The presence of ribonucleotides in DNA can lead to genomic instability and cellular lethality. To prevent adventitious rNTP incorporation, the majority of the DNA polymerases (dPols) possess a steric filter. The dPol named MsDpo4 (Mycobacterium smegmatis) naturally lacks this steric filter and hence is capable of rNTP addition. The introduction of the steric filter in MsDpo4 did not result in complete abrogation of the ability of this enzyme to incorporate ribonucleotides. In comparison, DNA polymerase IV (PolIV) from Escherichia coli exhibited stringent selection for deoxyribonucleotides. A comparison of MsDpo4 and PolIV led to the discovery of an additional polar filter responsible for sugar selectivity. Thr43 represents the filter in PolIV and this residue forms interactions with the incoming nucleotide to draw it closer to the enzyme surface. As a result, the 2’-OH in rNTPs will clash with the enzyme surface, and therefore ribonucleotides cannot be accommodated in the active site in a conformation compatible with productive catalysis. The substitution of the equivalent residue in MsDpo4–Cys47, with Thr led to a drastic reduction in the ability of the mycobacterial enzyme to incorporate rNTPs. Overall, our studies evince that the polar filter serves to prevent ribonucleotide incorporation by dPols.
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Affiliation(s)
- Mary K Johnson
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad 121001, India.,National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK Campus, Bangalore 560065, India
| | - Jithesh Kottur
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad 121001, India
| | - Deepak T Nair
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad 121001, India
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5
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Mammalian DNA Polymerase Kappa Activity and Specificity. Molecules 2019; 24:molecules24152805. [PMID: 31374881 PMCID: PMC6695781 DOI: 10.3390/molecules24152805] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 07/27/2019] [Accepted: 07/30/2019] [Indexed: 12/31/2022] Open
Abstract
DNA polymerase (pol) kappa is a Y-family translesion DNA polymerase conserved throughout all domains of life. Pol kappa is special6 ized for the ability to copy DNA containing minor groove DNA adducts, especially N2-dG adducts, as well as to extend primer termini containing DNA damage or mismatched base pairs. Pol kappa generally cannot copy DNA containing major groove modifications or UV-induced photoproducts. Pol kappa can also copy structured or non-B-form DNA, such as microsatellite DNA, common fragile sites, and DNA containing G quadruplexes. Thus, pol kappa has roles both in maintaining and compromising genomic integrity. The expression of pol kappa is altered in several different cancer types, which can lead to genome instability. In addition, many cancer-associated single-nucleotide polymorphisms have been reported in the POLK gene, some of which are associated with poor survival and altered chemotherapy response. Because of this, identifying inhibitors of pol kappa is an active area of research. This review will address these activities of pol kappa, with a focus on lesion bypass and cellular mutagenesis.
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Sørensen L, Salbo R. Optimized Workflow for Selecting Peptides for HDX-MS Data Analyses. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2018; 29:2278-2281. [PMID: 30171440 DOI: 10.1007/s13361-018-2056-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 08/09/2018] [Accepted: 08/09/2018] [Indexed: 06/08/2023]
Abstract
Hydrogen deuterium exchange measured by mass spectrometry (HDX-MS) is a commonly used technique for studying the structural dynamics of proteins in solution. The first part of any bottom-up HDX-MS experiment is to identify the peptides generated from a digestion step. This requires manual inspection of the identified peptides to determine their use for HDX-MS analysis, which is a time-consuming task. Throughout the literature, there have been different approaches for removing peptides that do not yield quantifiable HDX information. This includes using validity scores from the software used in the generation of the peptide map and that the peptide should be found in two out of three technical replicate experiments. Here, we analyze the previously available methods for filtering the identified peptides in regard to their ability to predict whether a peptide will provide quantifiable HDX-MS data or not. We also present a new score-based system relying on a combination of MS/MS parameters that offers an improved method for separating quantifiable peptides from the nonquantifiable. Using this score-based method reduces the number of peptide spectra that needs to be manually inspected and thereby the time spent curating HDX-MS data. Graphical Abstract ᅟ.
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Affiliation(s)
- Lars Sørensen
- Global Research Technologies, Novo Nordisk A/S, Novo Nordisk Park, DK-2760, Bagsværd, Denmark.
- Department of Molecular Biology and Genetics, University of Aarhus, Gustav Wieds Vej 10C, DK-8000, Aarhus C, Denmark.
| | - Rune Salbo
- Research and Development, Orion Corporation Orion Pharma, Tengströminkatu 8, FI-20360, Turku, Finland
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Antczak NM, Walker AR, Stern HR, Leddin EM, Palad C, Coulther TA, Swett RJ, Cisneros GA, Beuning PJ. Characterization of Nine Cancer-Associated Variants in Human DNA Polymerase κ. Chem Res Toxicol 2018; 31:697-711. [PMID: 30004685 DOI: 10.1021/acs.chemrestox.8b00055] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Specialized DNA damage-bypass Y-family DNA polymerases contribute to cancer prevention by providing cellular tolerance to DNA damage that can lead to mutations and contribute to cancer progression by increasing genomic instability. Y-family polymerases can also bypass DNA adducts caused by chemotherapy agents. One of the four human Y-family DNA polymerases, DNA polymerase (pol) κ, has been shown to be specific for bypass of minor groove adducts and inhibited by major groove adducts. In addition, mutations in the gene encoding pol κ are associated with different types of cancers as well as with chemotherapy responses. We characterized nine variants of pol κ whose identity was inferred from cancer-associated single nucleotide polymorphisms for polymerization activity on undamaged and damaged DNA, their abilities to extend from mismatched or damaged base pairs at primer termini, and overall stability and dynamics. We find that these pol κ variants generally fall into three categories: similar activity to wild-type (WT) pol κ (L21F, I39T, P169T, F192C, and E292K), more active than WT pol κ (S423R), and less active than pol κ (R219I, R298H, and Y432S). Of these, only pol κ variants R298H and Y432S had markedly reduced thermal stability. Molecular dynamics (MD) simulations with undamaged DNA revealed that the active variant F192C and more active variant S423R with either correct or incorrect incoming nucleotide mimic WT pol κ with the correct incoming nucleotide, whereas the less active variants R219I, R298H, and Y432S with the correct incoming nucleotide mimic WT pol κ with the incorrect incoming nucleotide. Thus, the observations from MD simulations suggest a possible explanation for the observed experimental results that pol κ adopts specific active and inactive conformations that depend on both the protein variant and the identity of the DNA adduct.
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Affiliation(s)
- Nicole M Antczak
- Department of Chemistry and Chemical Biology , Northeastern University , Boston , Massachusetts 02115 , United States
| | - Alice R Walker
- Department of Chemistry , University of North Texas , Denton , Texas 76203 , United States
| | - Hannah R Stern
- Department of Chemistry and Chemical Biology , Northeastern University , Boston , Massachusetts 02115 , United States
| | - Emmett M Leddin
- Department of Chemistry , University of North Texas , Denton , Texas 76203 , United States
| | - Carl Palad
- Department of Chemistry and Chemical Biology , Northeastern University , Boston , Massachusetts 02115 , United States
| | - Timothy A Coulther
- Department of Chemistry and Chemical Biology , Northeastern University , Boston , Massachusetts 02115 , United States
| | - Rebecca J Swett
- Vertex Pharmaceuticals , Boston , Massachusetts 02210 , United States
| | - G Andrés Cisneros
- Department of Chemistry , University of North Texas , Denton , Texas 76203 , United States
| | - Penny J Beuning
- Department of Chemistry and Chemical Biology , Northeastern University , Boston , Massachusetts 02115 , United States
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8
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Vaisman A, Woodgate R. Ribonucleotide discrimination by translesion synthesis DNA polymerases. Crit Rev Biochem Mol Biol 2018; 53:382-402. [PMID: 29972306 DOI: 10.1080/10409238.2018.1483889] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The well-being of all living organisms relies on the accurate duplication of their genomes. This is usually achieved by highly elaborate replicase complexes which ensure that this task is accomplished timely and efficiently. However, cells often must resort to the help of various additional "specialized" DNA polymerases that gain access to genomic DNA when replication fork progression is hindered. One such specialized polymerase family consists of the so-called "translesion synthesis" (TLS) polymerases; enzymes that have evolved to replicate damaged DNA. To fulfill their main cellular mission, TLS polymerases often must sacrifice precision when selecting nucleotide substrates. Low base-substitution fidelity is a well-documented inherent property of these enzymes. However, incorrect nucleotide substrates are not only those which do not comply with Watson-Crick base complementarity, but also those whose sugar moiety is incorrect. Does relaxed base-selectivity automatically mean that the TLS polymerases are unable to efficiently discriminate between ribonucleoside triphosphates and deoxyribonucleoside triphosphates that differ by only a single atom? Which strategies do TLS polymerases employ to select suitable nucleotide substrates? In this review, we will collate and summarize data accumulated over the past decade from biochemical and structural studies, which aim to answer these questions.
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Affiliation(s)
- Alexandra Vaisman
- a Laboratory of Genomic Integrity , National Institute of Child Health and Human Development, National Institutes of Health , Bethesda , MD , USA
| | - Roger Woodgate
- a Laboratory of Genomic Integrity , National Institute of Child Health and Human Development, National Institutes of Health , Bethesda , MD , USA
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9
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Antczak NM, Packer MR, Lu X, Zhang K, Beuning PJ. Human Y-Family DNA Polymerase κ Is More Tolerant to Changes in Its Active Site Loop than Its Ortholog Escherichia coli DinB. Chem Res Toxicol 2017; 30:2002-2012. [PMID: 28823149 DOI: 10.1021/acs.chemrestox.7b00175] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
DNA damage is a constant threat and can be bypassed in a process called translesion synthesis, which is typically carried out by Y-family DNA polymerases. Y-family DNA polymerases are conserved in all domains of life and tend to have specificity for certain types of DNA damage. Escherichia coli DinB and its human ortholog pol κ can bypass specific minor groove deoxyguanine adducts efficiently and are inhibited by major groove adducts, as Y-family DNA polymerases make contacts with the minor groove side of the DNA substrate and lack contacts with the major groove at the nascent base pair. DinB is inhibited by major groove adducts more than pol κ, and they each have active site loops of different lengths, with four additional amino acids in the DinB loop. We previously showed that the R35A active site loop mutation in DinB allows for bypass of the major groove adduct N6-furfuryl-dA. These observations led us to investigate the different active site loops by creating loop swap chimeras of DinB with a pol κ loop and vice versa by changing the loop residues in a stepwise fashion. We then determined their activity with undamaged DNA or DNA containing N2-furfuryl-dG or N6-furfuryl-dA. The DinB proteins with the pol kappa loop have low activity on all templates but have decreased misincorporation compared to either wild-type protein. The kappa proteins with the DinB loop retain activity on all templates and have decreased misincorporation compared to either wild-type protein. We assessed the thermal stability of the proteins and observed an increase in stability in the presence of all DNA templates and additional increases generally only in the presence of the undamaged and N2-furfuryl-dG adduct and dCTP, which correlates with activity. Overall we find that pol κ is more tolerant to changes in the active site loop than DinB.
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Affiliation(s)
- Nicole M Antczak
- Department of Chemistry & Chemical Biology, Northeastern University , Boston, Massachusetts 02115, United States
| | - Morgan R Packer
- Department of Chemistry & Chemical Biology, Northeastern University , Boston, Massachusetts 02115, United States
| | - Xueguang Lu
- Department of Chemistry & Chemical Biology, Northeastern University , Boston, Massachusetts 02115, United States
| | - Ke Zhang
- Department of Chemistry & Chemical Biology, Northeastern University , Boston, Massachusetts 02115, United States
| | - Penny J Beuning
- Department of Chemistry & Chemical Biology, Northeastern University , Boston, Massachusetts 02115, United States
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10
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AraC-like transcriptional activator CuxR binds c-di-GMP by a PilZ-like mechanism to regulate extracellular polysaccharide production. Proc Natl Acad Sci U S A 2017; 114:E4822-E4831. [PMID: 28559336 DOI: 10.1073/pnas.1702435114] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cyclic dimeric GMP (c-di-GMP) has emerged as a key regulatory player in the transition between planktonic and sedentary biofilm-associated bacterial lifestyles. It controls a multitude of processes including production of extracellular polysaccharides (EPSs). The PilZ domain, consisting of an N-terminal "RxxxR" motif and a β-barrel domain, represents a prototype c-di-GMP receptor. We identified a class of c-di-GMP-responsive proteins, represented by the AraC-like transcription factor CuxR in plant symbiotic α-proteobacteria. In Sinorhizobium meliloti, CuxR stimulates transcription of an EPS biosynthesis gene cluster at elevated c-di-GMP levels. CuxR consists of a Cupin domain, a helical hairpin, and bipartite helix-turn-helix motif. Although unrelated in sequence, the mode of c-di-GMP binding to CuxR is highly reminiscent to that of PilZ domains. c-di-GMP interacts with a conserved N-terminal RxxxR motif and the Cupin domain, thereby promoting CuxR dimerization and DNA binding. We unravel structure and mechanism of a previously unrecognized c-di-GMP-responsive transcription factor and provide insights into the molecular evolution of c-di-GMP binding to proteins.
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11
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Tashjian TF, Lin I, Belt V, Cafarelli TM, Godoy VG. RNA Primer Extension Hinders DNA Synthesis by Escherichia coli Mutagenic DNA Polymerase IV. Front Microbiol 2017; 8:288. [PMID: 28298904 PMCID: PMC5331060 DOI: 10.3389/fmicb.2017.00288] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 02/13/2017] [Indexed: 11/13/2022] Open
Abstract
In Escherichia coli the highly conserved DNA damage regulated dinB gene encodes DNA Polymerase IV (DinB), an error prone specialized DNA polymerase with a central role in stress-induced mutagenesis. Since DinB is the DNA polymerase with the highest intracellular concentrations upon induction of the SOS response, further regulation must exist to maintain genomic stability. Remarkably, we find that DinB DNA synthesis is inherently poor when using an RNA primer compared to a DNA primer, while high fidelity DNA polymerases are known to have no primer preference. Moreover, we show that the poor DNA synthesis from an RNA primer is conserved in DNA polymerase Kappa, the human DinB homolog. The activity of DinB is modulated by interactions with several other proteins, one of which is the equally evolutionarily conserved recombinase RecA. This interaction is known to positively affect DinB's fidelity on damaged templates. We find that upon interaction with RecA, DinB shows a significant reduction in DNA synthesis when using an RNA primer. Furthermore, with DinB or DinB:RecA a robust pause, sequence and lesion independent, occurs only when RNA is used as a primer. The robust pause is likely to result in abortive DNA synthesis when RNA is the primer. These data suggest a novel mechanism to prevent DinB synthesis when it is not needed despite its high concentrations, thus protecting genome stability.
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Affiliation(s)
- Tommy F Tashjian
- Godoy Lab, Department of Biology, Northeastern University Boston, MA, USA
| | - Ida Lin
- Godoy Lab, Department of Biology, Northeastern University Boston, MA, USA
| | - Verena Belt
- Godoy Lab, Department of Biology, Northeastern University Boston, MA, USA
| | | | - Veronica G Godoy
- Godoy Lab, Department of Biology, Northeastern University Boston, MA, USA
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12
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The excluded DNA strand is SEW important for hexameric helicase unwinding. Methods 2016; 108:79-91. [DOI: 10.1016/j.ymeth.2016.04.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 04/07/2016] [Accepted: 04/07/2016] [Indexed: 02/04/2023] Open
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13
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Graham BW, Tao Y, Dodge KL, Thaxton CT, Olaso D, Young NL, Marshall AG, Trakselis MA. DNA Interactions Probed by Hydrogen-Deuterium Exchange (HDX) Fourier Transform Ion Cyclotron Resonance Mass Spectrometry Confirm External Binding Sites on the Minichromosomal Maintenance (MCM) Helicase. J Biol Chem 2016; 291:12467-12480. [PMID: 27044751 DOI: 10.1074/jbc.m116.719591] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Indexed: 11/06/2022] Open
Abstract
The archaeal minichromosomal maintenance (MCM) helicase from Sulfolobus solfataricus (SsoMCM) is a model for understanding structural and mechanistic aspects of DNA unwinding. Although interactions of the encircled DNA strand within the central channel provide an accepted mode for translocation, interactions with the excluded strand on the exterior surface have mostly been ignored with regard to DNA unwinding. We have previously proposed an extension of the traditional steric exclusion model of unwinding to also include significant contributions with the excluded strand during unwinding, termed steric exclusion and wrapping (SEW). The SEW model hypothesizes that the displaced single strand tracks along paths on the exterior surface of hexameric helicases to protect single-stranded DNA (ssDNA) and stabilize the complex in a forward unwinding mode. Using hydrogen/deuterium exchange monitored by Fourier transform ion cyclotron resonance MS, we have probed the binding sites for ssDNA, using multiple substrates targeting both the encircled and excluded strand interactions. In each experiment, we have obtained >98.7% sequence coverage of SsoMCM from >650 peptides (5-30 residues in length) and are able to identify interacting residues on both the interior and exterior of SsoMCM. Based on identified contacts, positively charged residues within the external waist region were mutated and shown to generally lower DNA unwinding without negatively affecting the ATP hydrolysis. The combined data globally identify binding sites for ssDNA during SsoMCM unwinding as well as validating the importance of the SEW model for hexameric helicase unwinding.
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Affiliation(s)
- Brian W Graham
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Yeqing Tao
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306
| | - Katie L Dodge
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76798
| | - Carly T Thaxton
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76798
| | - Danae Olaso
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76798
| | - Nicolas L Young
- National High Magnetic Field Laboratory, Tallahassee, Florida 32310
| | - Alan G Marshall
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306; National High Magnetic Field Laboratory, Tallahassee, Florida 32310
| | - Michael A Trakselis
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76798.
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14
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Nevin P, Lu X, Zhang K, Engen JR, Beuning PJ. Noncognate DNA damage prevents the formation of the active conformation of the Y-family DNA polymerases DinB and DNA polymerase κ. FEBS J 2015; 282:2646-60. [PMID: 25899385 DOI: 10.1111/febs.13304] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Revised: 04/17/2015] [Accepted: 04/20/2015] [Indexed: 01/24/2023]
Abstract
Y-family DNA polymerases are specialized to copy damaged DNA, and are associated with increased mutagenesis, owing to their low fidelity. It is believed that the mechanism of nucleotide selection by Y-family DNA polymerases involves conformational changes preceding nucleotidyl transfer, but there is limited experimental evidence for such structural changes. In particular, nucleotide-induced conformational changes in bacterial or eukaryotic Y-family DNA polymerases have, to date, not been extensively characterized. Using hydrogen-deuterium exchange mass spectrometry, we demonstrate here that the Escherichia coli Y-family DNA polymerase DinB and its human ortholog DNA polymerase κ undergo a conserved nucleotide-induced conformational change in the presence of undamaged DNA and the correct incoming nucleotide. Notably, this holds true for damaged DNA containing N(2) -furfuryl-deoxyguanosine, which is efficiently copied by these two polymerases, but not for damaged DNA containing the major groove modification O(6) -methyl-deoxyguanosine, which is a poor substrate. Our observations suggest that DinB and DNA polymerase κ utilize a common mechanism for nucleotide selection involving a conserved prechemical conformational transition promoted by the correct nucleotide and only preferred DNA substrates.
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Affiliation(s)
- Philip Nevin
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, USA
| | - Xueguang Lu
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, USA
| | - Ke Zhang
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, USA
| | - John R Engen
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, USA
| | - Penny J Beuning
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, USA
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