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Thakur M, Muniyappa K. Macrophage activation highlight an important role for NER proteins in the survival, latency and multiplication of Mycobacterium tuberculosis. Tuberculosis (Edinb) 2023; 138:102284. [PMID: 36459831 DOI: 10.1016/j.tube.2022.102284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 11/14/2022] [Accepted: 11/20/2022] [Indexed: 11/27/2022]
Abstract
Nucleotide excision repair (NER) is one of the most extensively studied DNA repair processes in both prokaryotes and eukaryotes. The NER pathway is a highly conserved, ATP-dependent multi-step process involving several proteins/enzymes that function in a concerted manner to recognize and excise a wide spectrum of helix-distorting DNA lesions and bulky adducts by nuclease cleavage on either side of the damaged bases. As such, the NER pathway of Mycobacterium tuberculosis (Mtb) is essential for its survival within the hostile environment of macrophages and disease progression. This review focuses on present published knowledge about the crucial roles of Mtb NER proteins in the survival and multiplication of the pathogen within the macrophages and as potential targets for drug discovery.
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Affiliation(s)
- Manoj Thakur
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560012, India.
| | - K Muniyappa
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560012, India
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2
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Ailloud F, Estibariz I, Pfaffinger G, Suerbaum S. The Helicobacter pylori UvrC Nuclease Is Essential for Chromosomal Microimports after Natural Transformation. mBio 2022; 13:e0181122. [PMID: 35876509 DOI: 10.1128/mbio.01811-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Helicobacter pylori is a Gram-negative bacterial carcinogenic pathogen that infects the stomachs of half of the human population. It is a natural mutator due to a deficient DNA mismatch repair pathway and is naturally competent for transformation. As a result, it is one of the most genetically diverse human bacterial pathogens. The length of chromosomal imports in H. pylori follows an unusual bimodal distribution consisting of macroimports with a mean length of 1,645 bp and microimports with a mean length of 28 bp. The mechanisms responsible for this import pattern were unknown. Here, we used a high-throughput whole-genome transformation assay to elucidate the role of nucleotide excision repair pathway (NER) components on import length distribution. The data show that the integration of microimports depended on the activity of the UvrC endonuclease, while none of the other components of the NER pathway was required. Using H. pylori site-directed mutants, we showed that the widely conserved UvrC nuclease active sites, while essential for protection from UV light, one of the canonical NER functions, are not required for generation of microimports. A quantitative analysis of recombination patterns based on over 1,000 imports from over 200 sequenced recombinant genomes showed that microimports occur frequently within clusters of multiple imports, strongly suggesting they derive from a single strand invasion event. We propose a hypothetical model of homologous recombination in H. pylori, involving a novel function of UvrC, that reconciles the available experimental data about recombination patterns in H. pylori. IMPORTANCE Helicobacter pylori is one of the most common and genetically diverse human bacterial pathogens. It is responsible for chronic gastritis and represents the main risk factor for gastric cancer. In H. pylori, DNA fragments can be imported by recombination during natural transformation. The length of those fragments determines how many potentially beneficial or deleterious alleles are acquired and thus influences adaptation to the gastric niche. Here, we used a transformation assay to examine imported fragments across the chromosome. We show that UvrC, an endonuclease involved in DNA repair, is responsible for the specific integration of short DNA fragments. This suggests that short and long fragments are imported through distinct recombination pathways. We also show that short fragments are frequently clustered with longer fragments, suggesting that both pathways may be mechanistically linked. These findings provide a novel basis to explain how H. pylori can fine-tune the genetic diversity acquired by transformation.
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Thakur M, Parulekar RS, Barale SS, Sonawane KD, Muniyappa K. Interrogating the substrate specificity landscape of UvrC reveals novel insights into its non-canonical function. Biophys J 2022; 121:3103-3125. [PMID: 35810330 PMCID: PMC9463653 DOI: 10.1016/j.bpj.2022.07.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 05/23/2022] [Accepted: 07/07/2022] [Indexed: 11/29/2022] Open
Abstract
Although it is relatively unexplored, accumulating data highlight the importance of tripartite crosstalk between nucleotide excision repair (NER), DNA replication, and recombination in the maintenance of genome stability; however, elucidating the underlying mechanisms remains challenging. While Escherichia coli uvrA and uvrB can fully complement polAΔ cells in DNA replication, uvrC attenuates this alternative DNA replication pathway, but the exact mechanism by which uvrC suppresses DNA replication is unknown. Furthermore, the identity of bona fide canonical and non-canonical substrates for UvrCs are undefined. Here, we reveal that Mycobacterium tuberculosis UvrC (MtUvrC) strongly binds to, and robustly cleaves, key intermediates of DNA replication/recombination as compared with the model NER substrates. Notably, inactivation of MtUvrC ATPase activity significantly attenuated its endonuclease activity, thus suggesting a causal link between these two functions. We built an in silico model of the interaction of MtUvrC with the Holliday junction (HJ), using a combination of homology modeling, molecular docking, and molecular dynamic simulations. The model predicted residues that were potentially involved in HJ binding. Six of these residues were mutated either singly or in pairs, and the resulting MtUvrC variants were purified and characterized. Among them, residues Glu595 and Arg597 in the helix-hairpin-helix motif were found to be crucial for the interaction between MtUvrC and HJ; consequently, mutations in these residues, or inhibition of ATP hydrolysis, strongly abrogated its DNA-binding and endonuclease activities. Viewed together, these findings expand the substrate specificity landscape of UvrCs and provide crucial mechanistic insights into the interplay between NER and DNA replication/recombination.
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Affiliation(s)
- Manoj Thakur
- Department of Biochemistry, Indian Institute of Science, Bengaluru, India.
| | | | - Sagar S Barale
- Structural Bioinformatics Unit, Shivaji University, Kolhapur, India
| | - Kailas D Sonawane
- Department of Microbiology, Shivaji University, Kolhapur, India; Structural Bioinformatics Unit, Shivaji University, Kolhapur, India
| | - Kalappa Muniyappa
- Department of Biochemistry, Indian Institute of Science, Bengaluru, India.
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Thakur M, Agarwal A, Muniyappa K. The intrinsic ATPase activity of Mycobacterium tuberculosis UvrC is crucial for its damage-specific DNA incision function. FEBS J 2020; 288:1179-1200. [PMID: 32602194 DOI: 10.1111/febs.15465] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 05/04/2020] [Accepted: 06/24/2020] [Indexed: 11/28/2022]
Abstract
To ensure genome stability, bacteria have evolved a network of DNA repair mechanisms; among them, the UvrABC-dependent nucleotide excision repair (NER) pathway is essential for the incision of a variety of bulky adducts generated by exogenous chemicals, UV radiation and by-products of cellular metabolism. However, very little is known about the enzymatic properties of Mycobacterium tuberculosis UvrABC excinuclease complex. Furthermore, the biochemical properties of Escherichia coli UvrC (EcUvrC) are not well understood (compared to UvrA and UvrB), perhaps due to its limited availability and/or activity instability in vitro. In addition, homology modelling of M. tuberculosis UvrC (MtUvrC) revealed the presence of a putative ATP-binding pocket, although its function remains unknown. To elucidate the biochemical properties of UvrC, we constructed and purified wild-type MtUvrC and its eight variants harbouring mutations within the ATP-binding pocket. The data from DNA-binding studies suggest that MtUvrC exhibits high-affinity for duplex DNA containing a bubble or fluorescein-dT moiety, over fluorescein-adducted single-stranded DNA. Most notably, MtUvrC has an intrinsic UvrB-independent ATPase activity, which drives dual incision of the damaged DNA strand. In contrast, EcUvrC is devoid of ATPase activity; however, it retains the ability to bind ATP at levels comparable to that of MtUvrC. The ATPase-deficient variants map to residues lining the MtUvrC ATP-binding pocket. Further analysis of these variants revealed separation of function between ATPase and DNA-binding activities in MtUvrC. Altogether, these findings reveal functional diversity of the bacterial NER machinery and a paradigm for the evolution of a catalytic scaffold in UvrC.
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Affiliation(s)
- Manoj Thakur
- Department of Biochemistry, Indian Institute of Science, Bengaluru, India
| | - Ankit Agarwal
- Department of Biochemistry, Indian Institute of Science, Bengaluru, India
| | - Kalappa Muniyappa
- Department of Biochemistry, Indian Institute of Science, Bengaluru, India
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5
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Abstract
Recent advances have led to numerous landmark discoveries of [4Fe4S] clusters coordinated by essential enzymes in repair, replication, and transcription across all domains of life. The cofactor has notably been challenging to observe for many nucleic acid processing enzymes due to several factors, including a weak bioinformatic signature of the coordinating cysteines and lability of the metal cofactor. To overcome these challenges, we have used sequence alignments, an anaerobic purification method, iron quantification, and UV-visible and electron paramagnetic resonance spectroscopies to investigate UvrC, the dual-incision endonuclease in the bacterial nucleotide excision repair (NER) pathway. The characteristics of UvrC are consistent with [4Fe4S] coordination with 60-70% cofactor incorporation, and additionally, we show that, bound to UvrC, the [4Fe4S] cofactor is susceptible to oxidative degradation with aggregation of apo species. Importantly, in its holo form with the cofactor bound, UvrC forms high affinity complexes with duplexed DNA substrates; the apparent dissociation constants to well-matched and damaged duplex substrates are 100 ± 20 nM and 80 ± 30 nM, respectively. This high affinity DNA binding contrasts reports made for isolated protein lacking the cofactor. Moreover, using DNA electrochemistry, we find that the cluster coordinated by UvrC is redox-active and participates in DNA-mediated charge transport chemistry with a DNA-bound midpoint potential of 90 mV vs NHE. This work highlights that the [4Fe4S] center is critical to UvrC.
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Affiliation(s)
- Rebekah M B Silva
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Michael A Grodick
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Jacqueline K Barton
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
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Thakur M, Badugu S, Muniyappa K. UvrA and UvrC subunits of the Mycobacterium tuberculosis UvrABC excinuclease interact independently of UvrB and DNA. FEBS Lett 2019; 594:851-863. [PMID: 31705809 DOI: 10.1002/1873-3468.13671] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 10/31/2019] [Accepted: 10/31/2019] [Indexed: 11/10/2022]
Abstract
The UvrABC excinuclease plays a vital role in bacterial nucleotide excision repair. While UvrA and UvrB subunits associate to form a UvrA2 B2 complex, interaction between UvrA and UvrC has not been demonstrated or quantified in any bacterial species. Here, using Mycobacterium tuberculosis UvrA (MtUvrA), UvrB (MtUvrB) and UvrC (MtUvrC) subunits, we show that MtUvrA binds to MtUvrB and equally well to MtUvrC with submicromolar affinity. Furthermore, MtUvrA forms a complex with MtUvrC both in vivo and in vitro, independently of DNA and UvrB. Collectively, these findings reveal new insights into the pairwise relationships between the subunits of the UvrABC incision complex.
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Affiliation(s)
- Manoj Thakur
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Sugith Badugu
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Kalappa Muniyappa
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
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7
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Bavi R, Kumar R, Rampogu S, Son M, Park C, Baek A, Kim HH, Suh JK, Park SJ, Lee KW. Molecular interactions of UvrB protein and DNA from Helicobacter pylori: Insight into a molecular modeling approach. Comput Biol Med 2016; 75:181-9. [PMID: 27315565 DOI: 10.1016/j.compbiomed.2016.06.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 06/02/2016] [Accepted: 06/03/2016] [Indexed: 12/11/2022]
Abstract
Helicobacter pylori (H. pylori) persevere in the human stomach, an environment in which they encounter many DNA-damaging conditions, including gastric acidity. The pathogenicity of H. pylori is enhanced by its well-developed DNA repair mechanism, thought of as 'machinery,' such as nucleotide excision repair (NER). NER involves multi-enzymatic excinuclease proteins (UvrABC endonuclease), which repair damaged DNA in a sequential manner. UvrB is the central component in prokaryotic NER, essential for damage recognition. Therefore, molecular modeling studies of UvrB protein from H. pylori are carried out with homology modeling and molecular dynamics (MD) simulations. The results reveal that the predicted structure is bound to a DNA hairpin with 3-bp stem, an 11-nucleotide loop, and 3-nt 3' overhang. In addition, a mutation of the Y96A variant indicates reduction in the binding affinity for DNA. Free-energy calculations demonstrate the stability of the complex and help identify key residues in various interactions based on residue decomposition analysis. Stability comparative studies between wild type and mutant protein-DNA complexes indicate that the former is relatively more stable than the mutant form. This predicted model could also be useful in designing new inhibitors for UvrB protein, as well as preventing the pathogenesis of H. pylori.
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Affiliation(s)
- Rohit Bavi
- Division of Applied Life Science (BK21 Plus), Systems and Synthetic Agrobiotech Center (SSAC), Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Research Institute of Natural Science (RINS), Gyeongsang National University (GNU), 501 Jinju-daero, Jinju 52828, Republic of Korea
| | - Raj Kumar
- Division of Applied Life Science (BK21 Plus), Systems and Synthetic Agrobiotech Center (SSAC), Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Research Institute of Natural Science (RINS), Gyeongsang National University (GNU), 501 Jinju-daero, Jinju 52828, Republic of Korea
| | - Shailima Rampogu
- Division of Applied Life Science (BK21 Plus), Systems and Synthetic Agrobiotech Center (SSAC), Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Research Institute of Natural Science (RINS), Gyeongsang National University (GNU), 501 Jinju-daero, Jinju 52828, Republic of Korea
| | - Minky Son
- Division of Applied Life Science (BK21 Plus), Systems and Synthetic Agrobiotech Center (SSAC), Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Research Institute of Natural Science (RINS), Gyeongsang National University (GNU), 501 Jinju-daero, Jinju 52828, Republic of Korea
| | - Chanin Park
- Division of Applied Life Science (BK21 Plus), Systems and Synthetic Agrobiotech Center (SSAC), Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Research Institute of Natural Science (RINS), Gyeongsang National University (GNU), 501 Jinju-daero, Jinju 52828, Republic of Korea
| | - Ayoung Baek
- Division of Applied Life Science (BK21 Plus), Systems and Synthetic Agrobiotech Center (SSAC), Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Research Institute of Natural Science (RINS), Gyeongsang National University (GNU), 501 Jinju-daero, Jinju 52828, Republic of Korea
| | - Hyong-Ha Kim
- Division of Quality of Life, Korea Research Institute of Standards and Science, Daejeon 305-340, Republic of Korea
| | - Jung-Keun Suh
- Bio Computing Major, Korean German Institute of Technology, Seoul 157-033, Republic of Korea
| | - Seok Ju Park
- Department of Internal Medicine, College of Medicine, Busan Paik Hospital, Inje University, Republic of Korea.
| | - Keun Woo Lee
- Division of Applied Life Science (BK21 Plus), Systems and Synthetic Agrobiotech Center (SSAC), Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Research Institute of Natural Science (RINS), Gyeongsang National University (GNU), 501 Jinju-daero, Jinju 52828, Republic of Korea.
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8
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Parulekar RS, Barage SH, Jalkute CB, Dhanavade MJ, Fandilolu PM, Sonawane KD. Homology Modeling, Molecular Docking and DNA Binding Studies of Nucleotide Excision Repair UvrC Protein from M. tuberculosis. Protein J 2013; 32:467-76. [DOI: 10.1007/s10930-013-9506-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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9
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Andersson CE, Lagerbäck P, Carlson K. Structure of bacteriophage T4 endonuclease II mutant E118A, a tetrameric GIY-YIG enzyme. J Mol Biol 2010; 397:1003-16. [PMID: 20156453 DOI: 10.1016/j.jmb.2010.01.076] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Revised: 01/22/2010] [Accepted: 01/29/2010] [Indexed: 10/19/2022]
Abstract
Coliphage T4 endonuclease II (EndoII), encoded by gene denA, is a small (16 kDa, 136 aa) enzyme belonging to the GIY-YIG family of endonucleases, which lacks a C-terminal domain corresponding to that providing most of the binding energy in the structurally characterized GIY-YIG endonucleases, I-TevI and UvrC. In vivo, it is involved in degradation of host DNA, permitting scavenging of host-derived nucleotides for phage DNA synthesis. EndoII primarily catalyzes single-stranded nicking of DNA; 5- to 10-fold less frequently double-stranded breaks are produced. The Glu118Ala mutant of EndoII was crystallized in space group P2(1) with four monomers in the asymmetric unit. The fold of the EndoII monomer is similar to that of the catalytic domains of UvrC and I-TevI. In contrast to these enzymes, EndoII forms a striking X-shaped tetrameric structure composed as a dimer of dimers, with a protruding hairpin domain not present in UvrC or I-TevI providing most of the dimerization and tetramerization interfaces. A bound phosphate ion in one of the four active sites of EndoII likely mimics the scissile phosphate in a true substrate complex. In silico docking experiments showed that a protruding loop containing a nuclease-associated modular domain 3 element is likely to be involved in substrate binding, as well as residues forming a separate nucleic acid binding surface adjacent to the active site. The positioning of these sites within the EndoII primary dimer suggests that the substrate would bind to a primary EndoII dimer diagonally over the active sites, requiring significant distortion of the enzyme or the substrate DNA, or both, for simultaneous nicking of both DNA strands. The scarcity of potential nucleic acid binding residues between the active sites indicates that EndoII may bind its substrate inefficiently across the two sites in the dimer, offering a plausible explanation for the catalytic preponderance of single-strand nicks. Mutations analyzed in earlier functional studies are discussed in their structural context.
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Affiliation(s)
- C Evalena Andersson
- Department of Molecular Biology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
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10
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Lagerbäck P, Andersson E, Malmberg C, Carlson K. Bacteriophage T4 endonuclease II, a promiscuous GIY-YIG nuclease, binds as a tetramer to two DNA substrates. Nucleic Acids Res 2009; 37:6174-83. [PMID: 19666720 PMCID: PMC2764454 DOI: 10.1093/nar/gkp652] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The oligomerization state and mode of binding to DNA of the GIY-YIG endonuclease II (EndoII) from bacteriophage T4 was studied using gel filtration and electrophoretic mobility shift assays with a set of mutants previously found to have altered enzyme activity. At low enzyme/DNA ratios all mutants except one bound to DNA only as tetramers to two DNA substrates. The putatively catalytic E118 residue actually interfered with DNA binding (possibly due to steric hindrance or repulsion between the glutamate side chain and DNA), as shown by the ability of E118A to bind stably also as monomer or dimer to a single substrate. The tetrameric structure of EndoII in the DNA-protein complex is surprising considering the asymmetry of the recognized sequence and the predominantly single-stranded nicking. Combining the results obtained here with those from our previous in vivo studies and the recently obtained crystal structure of EndoII E118A, we suggest a model where EndoII translocates DNA between two adjacent binding sites and either nicks one strand of one or both substrates bound by the tetramer, or nicks both strands of one substrate. Thus, only one or two of the four active sites in the tetramer is catalytically active at any time.
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Affiliation(s)
- Pernilla Lagerbäck
- Department of Cell and Molecular Biology, University of Uppsala and Department of Molecular Biology, Swedish University of Agricultural Sciences, Uppsala, Sweden
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Jiang G, Skorvaga M, Croteau DL, Van Houten B, States JC. Robust incision of Benoz[a]pyrene-7,8-dihyrodiol-9,10-epoxide-DNA adducts by a recombinant thermoresistant interspecies combination UvrABC endonuclease system. Biochemistry 2006; 45:7834-43. [PMID: 16784235 PMCID: PMC2505190 DOI: 10.1021/bi052515e] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Prokaryotic DNA repair nucleases are useful reagents for detecting DNA lesions. UvrABC endonuclease, encoded by the UvrA, UvrB, and UvrC genes can incise DNA containing bulky nucleotide adducts and intrastrand cross-links. UvrA, UvrB, and UvrC were cloned from Bacillus caldotenax (Bca)and UvrC from Thermatoga maritima (Tma), and recombinant proteins were overexpressed in and purified from Escherichia coli. Incision activities of UvrABC composed of all Bca-derived subunits (UvrABC(Bca)) and an interspecies combination UvrABC composed of Bca-derived UvrA and UvrB and Tma-derived UvrC (UvrABC(Tma)) were compared on benoz[a]pyrene-7,8-dihyrodiol-9,10-epoxide (BPDE)-adducted substrates. Both UvrABC(Bca) and UvrABC(Tma) specifically incised both BPDE-adducted plasmid DNAs and site-specifically modified 50-bp oligonucleotides containing a single (+)-trans- or (+)-cis-BPDE adduct. Incision activity was maximal at 55-60 degrees C. However, UvrABC(Tma) was more robust than UvrABC(Bca) with 4-fold greater incision activity on BPDE-adducted oligonucleotides and 1.5-fold greater on [(3)H]BPDE-adducted plasmid DNAs. Remarkably, UvrABC(Bca) incised only at the eighth phosphodiester bond 5' to the BPDE-modified guanosine. In contrast, UvrABC(Tma) performed dual incision, cutting at both the fifth phosphodiester bond 3' and eighth phosphodiester bond 5' from BPDE-modified guanosine. BPDE adduct stereochemistry influenced incision activity, and cis adducts on oligonucleotide substrates were incised more efficiently than trans adducts by both UvrABC(Bca) and UvrABC(Tma). UvrAB-DNA complex formation was similar with (+)-trans- and (+)-cis-BPDE-adducted substrates, suggesting that UvrAB binds both adducts equally and that adduct configuration modifies UvrC recognition of the UvrAB-DNA complex. The dual incision capabilities and higher incision activity of UvrABC(Tma) make it a robust tool for DNA adduct studies.
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Affiliation(s)
- GuoHui Jiang
- Department of Pharmacology and Toxicology, Brown Cancer Center, and Center for Genetics and Molecular Medicine, University of Louisville, Louisville, KY
| | - Milan Skorvaga
- National Institute of Environmental Health Sciences, Research Triangle Park, NC
- Corresponding author: J. Christopher States, Ph. D., Department of Pharmacology and Toxicology, University of Louisville, 570 S. Preston St., Suite 221, Louisville, KY 40202, tel: 502-852-5347, fax: 502-852-2492,
| | - Deborah L. Croteau
- National Institute of Environmental Health Sciences, Research Triangle Park, NC
| | - Bennett Van Houten
- National Institute of Environmental Health Sciences, Research Triangle Park, NC
| | - J. Christopher States
- Department of Pharmacology and Toxicology, Brown Cancer Center, and Center for Genetics and Molecular Medicine, University of Louisville, Louisville, KY
- Corresponding author: J. Christopher States, Ph. D., Department of Pharmacology and Toxicology, University of Louisville, 570 S. Preston St., Suite 221, Louisville, KY 40202, tel: 502-852-5347, fax: 502-852-2492,
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Affiliation(s)
- James J Truglio
- Department of Pharmacological Sciences, State University of New York at Stony Brook, 11794-5115, USA
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13
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Affiliation(s)
- Joyce T Reardon
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA
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14
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Singh S, Folkers G, Bonvin A, Boelens R, Wechselberger R, Niztayev A, Kaptein R. Solution structure and DNA-binding properties of the C-terminal domain of UvrC from E.coli. EMBO J 2002; 21:6257-66. [PMID: 12426397 PMCID: PMC137216 DOI: 10.1093/emboj/cdf627] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The C-terminal domain of the UvrC protein (UvrC CTD) is essential for 5' incision in the prokaryotic nucleotide excision repair process. We have determined the three-dimensional structure of the UvrC CTD using heteronuclear NMR techniques. The structure shows two helix-hairpin-helix (HhH) motifs connected by a small connector helix. The UvrC CTD is shown to mediate structure-specific DNA binding. The domain binds to a single-stranded-double-stranded junction DNA, with a strong specificity towards looped duplex DNA that contains at least six unpaired bases per loop ("bubble DNA"). Using chemical shift perturbation experiments, the DNA-binding surface is mapped to the first hairpin region encompassing the conserved glycine-valine-glycine residues followed by lysine-arginine-arginine, a positively charged surface patch and the second hairpin region consisting of glycine-isoleucine-serine. A model for the protein-DNA complex is proposed that accounts for this specificity.
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Affiliation(s)
| | | | | | | | | | | | - R. Kaptein
- Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
Corresponding author e-mail:
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15
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Affiliation(s)
- Bennett Van Houten
- Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
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Tang MS, Pfeifer GP, Denissenko MF, Feng Z, Hu W, Pao A, Zheng Y, Zheng JB, Li H, Chen JX. Mapping polycyclic aromatic hydrocarbon and aromatic amine-induced DNA damage in cancer-related genes at the sequence level. Int J Hyg Environ Health 2002; 205:103-13. [PMID: 12018002 DOI: 10.1078/1438-4639-00135] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Genomic injury induced by environmental carcinogens, such as polycyclic aromatic hydrocarbons and aromatic amines, is the initial step that can trigger mutagenesis and carcinogenesis. In addition to the physico-chemical property of DNA damaging agents, several important factors such as primary sequence, chromatin structure, methylation, protein association, and transcriptional activity can affect not only the initial level and distribution of DNA damage but also the efficiency of repair. Therefore, mapping the DNA damage induced by environmental agents in cancer-related genes such as p53 and ras at the sequence level provides essential information for assessing their carcinogenic potential. Recently, using the E. coli nucleotide excision enzyme complex, UvrABC nucleases in combination with ligation-mediated polymerase chain reaction, we developed a method to map DNA damage in the p53 and ras genes. These studies led us to conclude that targeted DNA damage, in combination with growth selection, contributes greatly in shaping the mutation spectrum in these genes in human cancer. Here we present the rationale and details of this approach, typical experimental results and necessary precautions.
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Affiliation(s)
- Moon-shong Tang
- Department of Environmental Medicine, New York University School of Medicine, 57 Old Forge Road, Tuxedo, NY 10987, USA.
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Heeb S, Haas D. Regulatory roles of the GacS/GacA two-component system in plant-associated and other gram-negative bacteria. Mol Plant Microbe Interact 2001; 14:1351-1363. [PMID: 11768529 DOI: 10.1094/mpmi.2001.14.12.1351] [Citation(s) in RCA: 286] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The sensor kinase GacS and the response regulator GacA are members of a two-component system that is present in a wide variety of gram-negative bacteria and has been studied mainly in enteric bacteria and fluorescent pseudomonads. The GacS/GacA system controls the production of secondary metabolites and extracellular enzymes involved in pathogenicity to plants and animals, biocontrol of soilborne plant diseases, ecological fitness, or tolerance to stress. A current model proposes that GacS senses a still-unknown signal and activates, via a phosphorelay mechanism, the GacA transcription regulator, which in turn triggers the expression of target genes. The GacS protein belongs to the unorthodox sensor kinases, characterized by an autophosphorylation, a receiver, and an output domain. The periplasmic loop domain of GacS is poorly conserved in diverse bacteria. Thus, a common signal interacting with this domain would be unexpected. Based on a comparison with the transcriptional regulator NarL, a secondary structure can be predicted for the GacA sensor kinases. Certain genes whose expression is regulated by the GacS/GacA system are regulated in parallel by the small RNA binding protein RsmA (CsrA) at a posttranscriptional level. It is suggested that the GacS/GacA system operates a switch between primary and secondary metabolism, with a major involvement of posttranscriptional control mechanisms.
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Affiliation(s)
- S Heeb
- Laboratoire de Biologie Microbienne, Université de Lausanne, Switzerland
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