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Łazowski K, Woodgate R, Fijalkowska IJ. Escherichia coli DNA replication: the old model organism still holds many surprises. FEMS Microbiol Rev 2024; 48:fuae018. [PMID: 38982189 PMCID: PMC11253446 DOI: 10.1093/femsre/fuae018] [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: 05/09/2024] [Revised: 06/26/2024] [Accepted: 07/08/2024] [Indexed: 07/11/2024] Open
Abstract
Research on Escherichia coli DNA replication paved the groundwork for many breakthrough discoveries with important implications for our understanding of human molecular biology, due to the high level of conservation of key molecular processes involved. To this day, it attracts a lot of attention, partially by virtue of being an important model organism, but also because the understanding of factors influencing replication fidelity might be important for studies on the emergence of antibiotic resistance. Importantly, the wide access to high-resolution single-molecule and live-cell imaging, whole genome sequencing, and cryo-electron microscopy techniques, which were greatly popularized in the last decade, allows us to revisit certain assumptions about the replisomes and offers very detailed insight into how they work. For many parts of the replisome, step-by-step mechanisms have been reconstituted, and some new players identified. This review summarizes the latest developments in the area, focusing on (a) the structure of the replisome and mechanisms of action of its components, (b) organization of replisome transactions and repair, (c) replisome dynamics, and (d) factors influencing the base and sugar fidelity of DNA synthesis.
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Affiliation(s)
- Krystian Łazowski
- Laboratory of DNA Replication and Genome Stability, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warsaw, Poland
| | - Roger Woodgate
- Laboratory of Genomic Integrity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-3371, United States
| | - Iwona J Fijalkowska
- Laboratory of DNA Replication and Genome Stability, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warsaw, Poland
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Berger MB, Cisneros GA. Distal Mutations in the β-Clamp of DNA Polymerase III* Disrupt DNA Orientation and Affect Exonuclease Activity. J Am Chem Soc 2023; 145:3478-3490. [PMID: 36745735 PMCID: PMC10237177 DOI: 10.1021/jacs.2c11713] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
DNA polymerases are responsible for the replication and repair of DNA found in all DNA-based organisms. DNA Polymerase III is the main replicative polymerase of E. coli and is composed of over 10 proteins. A subset of these proteins (Pol III*) includes the polymerase (α), exonuclease (ϵ), clamp (β), and accessory protein (θ). Mutations of residues in, or around the active site of the catalytic subunits (α and ϵ), can have a significant impact on catalysis. However, the effects of distal mutations in noncatalytic subunits on the activity of catalytic subunits are less well-characterized. Here, we investigate the effects of two Pol III* variants, β-L82E/L82'E and β-L82D/L82'D, on the proofreading reaction catalyzed by ϵ. MD simulations reveal major changes in the dynamics of Pol III*, which extend throughout the complex. These changes are mostly induced by a shift in the position of the DNA substrate inside the β-clamp, although no major structural changes are observed in the protein complex. Quantum mechanics/molecular mechanics (QM/MM) calculations indicate that the β-L82D/L82'D variant has reduced catalytic proficiency due to highly endoergic reaction energies resulting from structural changes in the active site and differences in the electric field at the active site arising from the protein and substrate. Conversely, the β-L82E/L82'E variant is predicted to maintain proofreading activity, exhibiting a similar reaction barrier for nucleotide excision compared with the WT system. However, significant differences in the reaction mechanism are obtained due to the changes induced by the mutations on the β-clamp.
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Affiliation(s)
- Madison B Berger
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas 75080, United States
| | - G Andrés Cisneros
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas 75080, United States
- Department of Physics, University of Texas at Dallas, Richardson, Texas 75080, United States
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Turgimbayeva A, Zein U, Zharkov DO, Ramankulov Y, Saparbaev M, Abeldenov S. Cloning and characterization of the major AP endonuclease from Staphylococcus aureus. DNA Repair (Amst) 2022; 119:103390. [DOI: 10.1016/j.dnarep.2022.103390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 07/19/2022] [Accepted: 08/20/2022] [Indexed: 11/03/2022]
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Scotland MK, Homiski C, Sutton MD. During Translesion Synthesis, Escherichia coli DinB89 (T120P) Alters Interactions of DinB (Pol IV) with Pol III Subunit Assemblies and SSB, but Not with the β Clamp. J Bacteriol 2022; 204:e0061121. [PMID: 35285726 PMCID: PMC9017331 DOI: 10.1128/jb.00611-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 02/10/2022] [Indexed: 11/20/2022] Open
Abstract
Translesion synthesis (TLS) by specialized DNA polymerases (Pols) is an evolutionarily conserved mechanism for tolerating replication-blocking DNA lesions. Using the Escherichia coli dinB-encoded Pol IV as a model to understand how TLS is coordinated with the actions of the high-fidelity Pol III replicase, we previously described a novel Pol IV mutant containing a threonine 120-to-proline mutation (Pol IV-T120P) that failed to exchange places with Pol III at the replication fork in vitro as part of a Pol III-Pol IV switch. This in vitro defect correlated with the inability of Pol IV-T120P to support TLS in vivo, suggesting Pol IV gains access to the DNA, at least in part, via a Pol III-Pol IV switch. Interaction of Pol IV with the β sliding clamp and the single-stranded DNA binding protein (SSB) significantly stimulates Pol IV replication and facilitates its access to the DNA. In this work, we demonstrate that Pol IV interacts physically with Pol III. We further show that Pol IV-T120P interacts normally with the β clamp, but is impaired in interactions with the α catalytic and εθ proofreading subunits of Pol III, as well as SSB. Taken together with published work, these results provide strong support for the model in which Pol IV-Pol III and Pol IV-SSB interactions help to regulate the access of Pol IV to the DNA. Finally, we describe several additional E. coli Pol-Pol interactions, suggesting Pol-Pol interactions play fundamental roles in coordinating bacterial DNA replication, DNA repair, and TLS. IMPORTANCE Specialized DNA polymerases (Pols) capable of catalyzing translesion synthesis (TLS) generate mutations that contribute to bacterial virulence, pathoadaptation, and antimicrobial resistance. One mechanism by which the bacterial TLS Pol IV gains access to the DNA to generate mutations is by exchanging places with the bacterial Pol III replicase via a Pol III-Pol IV switch. Here, we describe multiple Pol III-Pol IV interactions and discuss evidence that these interactions are required for the Pol III-Pol IV switch. Furthermore, we describe several additional E. coli Pol-Pol interactions that may play fundamental roles in managing the actions of the different bacterial Pols in DNA replication, DNA repair, and TLS.
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Affiliation(s)
- Michelle K. Scotland
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York, USA
| | - Caleb Homiski
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York, USA
| | - Mark D. Sutton
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York, USA
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The Mutant β E202K Sliding Clamp Protein Impairs DNA Polymerase III Replication Activity. J Bacteriol 2021; 203:e0030321. [PMID: 34543108 DOI: 10.1128/jb.00303-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Expression of the Escherichia coli dnaN-encoded β clamp at ≥10-fold higher than chromosomally expressed levels impedes growth by interfering with DNA replication. We hypothesized that the excess β clamp sequesters the replicative DNA polymerase III (Pol III) to inhibit replication. As a test of this hypothesis, we obtained eight mutant clamps with an inability to impede growth and measured their ability to stimulate Pol III replication in vitro. Compared with the wild-type clamp, seven of the mutants were defective, consistent with their elevated cellular levels failing to sequester Pol III. However, the βE202K mutant that bears a glutamic acid-to-lysine substitution at residue 202 displayed an increased affinity for Pol IIIα and Pol III core (Pol IIIαεθ), suggesting that it could still sequester Pol III effectively. Of interest, βE202K supported in vitro DNA replication by Pol II and Pol IV but was defective with Pol III. Genetic experiments indicated that the dnaNE202K strain remained proficient in DNA damage-induced mutagenesis but was induced modestly for SOS and displayed sensitivity to UV light and methyl methanesulfonate. These results correlate an impaired ability of the mutant βE202K clamp to support Pol III replication in vivo with its in vitro defect in DNA replication. Taken together, our results (i) support the model that sequestration of Pol III contributes to growth inhibition, (ii) argue for the existence of an additional mechanism that contributes to lethality, and (iii) suggest that physical and functional interactions of the β clamp with Pol III are more extensive than appreciated currently. IMPORTANCE The β clamp plays critically important roles in managing the actions of multiple proteins at the replication fork. However, we lack a molecular understanding of both how the clamp interacts with these different partners and the mechanisms by which it manages their respective actions. We previously exploited the finding that an elevated cellular level of the β clamp impedes Escherichia coli growth by interfering with DNA replication. Using a genetic selection method, we obtained novel mutant β clamps that fail to inhibit growth. Their analysis revealed that βE202K is unique among them. Our work offers new insights into how the β clamp interacts with and manages the actions of E. coli DNA polymerases II, III, and IV.
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Nedal A, Ræder SB, Dalhus B, Helgesen E, Forstrøm RJ, Lindland K, Sumabe BK, Martinsen JH, Kragelund BB, Skarstad K, Bjørås M, Otterlei M. Peptides containing the PCNA interacting motif APIM bind to the β-clamp and inhibit bacterial growth and mutagenesis. Nucleic Acids Res 2020; 48:5540-5554. [PMID: 32347931 PMCID: PMC7261172 DOI: 10.1093/nar/gkaa278] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 04/06/2020] [Accepted: 04/08/2020] [Indexed: 01/08/2023] Open
Abstract
In the fight against antimicrobial resistance, the bacterial DNA sliding clamp, β-clamp, is a promising drug target for inhibition of DNA replication and translesion synthesis. The β-clamp and its eukaryotic homolog, PCNA, share a C-terminal hydrophobic pocket where all the DNA polymerases bind. Here we report that cell penetrating peptides containing the PCNA-interacting motif APIM (APIM-peptides) inhibit bacterial growth at low concentrations in vitro, and in vivo in a bacterial skin infection model in mice. Surface plasmon resonance analysis and computer modeling suggest that APIM bind to the hydrophobic pocket on the β-clamp, and accordingly, we find that APIM-peptides inhibit bacterial DNA replication. Interestingly, at sub-lethal concentrations, APIM-peptides have anti-mutagenic activities, and this activity is increased after SOS induction. Our results show that although the sequence homology between the β-clamp and PCNA are modest, the presence of similar polymerase binding pockets in the DNA clamps allows for binding of the eukaryotic binding motif APIM to the bacterial β-clamp. Importantly, because APIM-peptides display both anti-mutagenic and growth inhibitory properties, they may have clinical potential both in combination with other antibiotics and as single agents.
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Affiliation(s)
- Aina Nedal
- Department of Clinical and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, NTNU, 7489 Trondheim, Norway
| | - Synnøve B Ræder
- Department of Clinical and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, NTNU, 7489 Trondheim, Norway
| | - Bjørn Dalhus
- Department of Medical Biochemistry, Institute for Clinical Medicine, Oslo University Hospital and University of Oslo, 0424 Oslo, Norway.,Department of Microbiology, Oslo University Hospital, and University of Oslo, 0424, Oslo, Norway
| | - Emily Helgesen
- Department of Clinical and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, NTNU, 7489 Trondheim, Norway.,Department of Microbiology, Oslo University Hospital, and University of Oslo, 0424, Oslo, Norway
| | - Rune J Forstrøm
- Department of Microbiology, Oslo University Hospital, and University of Oslo, 0424, Oslo, Norway
| | - Kim Lindland
- Department of Clinical and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, NTNU, 7489 Trondheim, Norway
| | - Balagra K Sumabe
- Department of Clinical and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, NTNU, 7489 Trondheim, Norway
| | - Jacob H Martinsen
- Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, 2200, Copenhagen N, Denmark
| | - Birthe B Kragelund
- Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, 2200, Copenhagen N, Denmark
| | - Kirsten Skarstad
- Department of Microbiology, Oslo University Hospital, and University of Oslo, 0424, Oslo, Norway
| | - Magnar Bjørås
- Department of Clinical and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, NTNU, 7489 Trondheim, Norway.,Department of Microbiology, Oslo University Hospital, and University of Oslo, 0424, Oslo, Norway
| | - Marit Otterlei
- Department of Clinical and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, NTNU, 7489 Trondheim, Norway
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Maslowska KH, Makiela‐Dzbenska K, Fijalkowska IJ. The SOS system: A complex and tightly regulated response to DNA damage. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2019; 60:368-384. [PMID: 30447030 PMCID: PMC6590174 DOI: 10.1002/em.22267] [Citation(s) in RCA: 221] [Impact Index Per Article: 44.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 10/29/2018] [Accepted: 11/13/2018] [Indexed: 05/10/2023]
Abstract
Genomes of all living organisms are constantly threatened by endogenous and exogenous agents that challenge the chemical integrity of DNA. Most bacteria have evolved a coordinated response to DNA damage. In Escherichia coli, this inducible system is termed the SOS response. The SOS global regulatory network consists of multiple factors promoting the integrity of DNA as well as error-prone factors allowing for survival and continuous replication upon extensive DNA damage at the cost of elevated mutagenesis. Due to its mutagenic potential, the SOS response is subject to elaborate regulatory control involving not only transcriptional derepression, but also post-translational activation, and inhibition. This review summarizes current knowledge about the molecular mechanism of the SOS response induction and progression and its consequences for genome stability. Environ. Mol. Mutagen. 60:368-384, 2019. © 2018 The Authors. Environmental and Molecular Mutagenesis published by Wiley Periodicals, Inc. on behalf of Environmental Mutagen Society.
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Affiliation(s)
- Katarzyna H. Maslowska
- Cancer Research Center of Marseille, CNRS, UMR7258Inserm, U1068; Institut Paoli‐Calmettes, Aix‐Marseille UniversityMarseilleFrance
- Institute of Biochemistry and Biophysics, Polish Academy of SciencesWarsawPoland
| | | | - Iwona J. Fijalkowska
- Institute of Biochemistry and Biophysics, Polish Academy of SciencesWarsawPoland
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In vivo demonstration of enhanced binding between β-clamp and DnaE of pol III bearing consensus i-CBM. Genes Genomics 2019; 41:613-619. [PMID: 30929144 DOI: 10.1007/s13258-019-00796-9] [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: 10/04/2018] [Accepted: 02/15/2019] [Indexed: 10/27/2022]
Abstract
BACKGROUND Among several key protein-protein and protein-DNA interactions within the replisome, the interaction between β-clamp and the DNA polymerase (Pol) III is of crucial importance. This interaction is mediated by a five or six-residue conserved sequence of the DnaE subunit of Pol III, referred to as the Clamp Binding Motif (CBM). In E. coli, DnaE contains two CBMs designated as e-CBM and i-CBM. A consensus sequence (QL[S/D]LF) for the CBMs has previously been proposed and studies involving mutagenesis of both the CBMs have evaluated their protein-binding properties. Surface Plasmon Resonance has been used to show that replacing i-CBM in DnaE with the consensus sequence enhances its binding to β-clamp 120-fold. OBJECTIVE The current study was aimed to evaluate in vivo interaction between DnaE bearing the consensus i-CBM and β-clamp. METHOD The C-terminal 405 residues of DnaE, bearing either the consensus i-CBM or the WT i-CBM, with β-clamp were co-expressed in E. coli followed by co-purification of the protein complexes. The interaction was assessed by the ability of the co-expressed proteins to form stable complexes during both affinity and gel filtration chromatography. RESULT The interaction of β-clamp with DnaEΔ755M containing the consensus i-CBM was found to be more stable than with WT DnaEΔ755, consistent with the in vitro data previously reported. CONCLUSION The presence of the pieces of sheared DNA generated during sonication promote the interaction of DnaEΔ755M with β-clamp by binding the OB-fold of DnaEΔ755M and β-clamp and serves as a bridge between them.
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