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Dapkūnas J, Timinskas A, Olechnovič K, Tomkuvienė M, Venclovas Č. PPI3D: a web server for searching, analyzing and modeling protein-protein, protein-peptide and protein-nucleic acid interactions. Nucleic Acids Res 2024; 52:W264-W271. [PMID: 38619046 PMCID: PMC11223826 DOI: 10.1093/nar/gkae278] [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: 02/03/2024] [Revised: 03/19/2024] [Accepted: 04/03/2024] [Indexed: 04/16/2024] Open
Abstract
Structure-resolved protein interactions with other proteins, peptides and nucleic acids are key for understanding molecular mechanisms. The PPI3D web server enables researchers to query preprocessed and clustered structural data, analyze the results and make homology-based inferences for protein interactions. PPI3D offers three interaction exploration modes: (i) all interactions for proteins homologous to the query, (ii) interactions between two proteins or their homologs and (iii) interactions within a specific PDB entry. The server allows interactive analysis of the identified interactions in both summarized and detailed manner. This includes protein annotations, structures, the interface residues and the corresponding contact surface areas. In addition, users can make inferences about residues at the interaction interface for the query protein(s) from the sequence alignments and homology models. The weekly updated PPI3D database includes all the interaction interfaces and binding sites from PDB, clustered based on both protein sequence and structural similarity, yielding non-redundant datasets without loss of alternative interaction modes. Consequently, the PPI3D users avoid being flooded with redundant information, a typical situation for intensely studied proteins. Furthermore, PPI3D provides a possibility to download user-defined sets of interaction interfaces and analyze them locally. The PPI3D web server is available at https://bioinformatics.lt/ppi3d.
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Affiliation(s)
- Justas Dapkūnas
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Saulėtekio av. 7, Vilnius LT-10257, Lithuania
| | - Albertas Timinskas
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Saulėtekio av. 7, Vilnius LT-10257, Lithuania
| | - Kliment Olechnovič
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Saulėtekio av. 7, Vilnius LT-10257, Lithuania
- Univ. Grenoble Alpes, CNRS, Grenoble INP, LJK, 38000 Grenoble, France
| | - Miglė Tomkuvienė
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Saulėtekio av. 7, Vilnius LT-10257, Lithuania
| | - Česlovas Venclovas
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Saulėtekio av. 7, Vilnius LT-10257, Lithuania
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2
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Luo G, Ming T, Yang L, He L, Tao T, Wang Y. Modulators targeting protein-protein interactions in Mycobacterium tuberculosis. Microbiol Res 2024; 284:127675. [PMID: 38636239 DOI: 10.1016/j.micres.2024.127675] [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: 09/27/2023] [Revised: 03/03/2024] [Accepted: 03/04/2024] [Indexed: 04/20/2024]
Abstract
Tuberculosis (TB) is a chronic infectious disease caused by Mycobacterium tuberculosis (M. tuberculosis), mainly transmitted through droplets to infect the lungs, and seriously affecting patients' health and quality of life. Clinically, anti-TB drugs often entail side effects and lack efficacy against resistant strains. Thus, the exploration and development of novel targeted anti-TB medications are imperative. Currently, protein-protein interactions (PPIs) offer novel avenues for anti-TB drug development, and the study of targeted modulators of PPIs in M. tuberculosis has become a prominent research focus. Furthermore, a comprehensive PPI network has been constructed using computational methods and bioinformatics tools. This network allows for a more in-depth analysis of the structural biology of PPIs and furnishes essential insights for the development of targeted small-molecule modulators. Furthermore, this article provides a detailed overview of the research progress and regulatory mechanisms of PPI modulators in M. tuberculosis, the causative agent of TB. Additionally, it summarizes potential targets for anti-TB drugs and discusses the prospects of existing PPI modulators.
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Affiliation(s)
- Guofeng Luo
- School of Medical and Life Sciences, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Tianqi Ming
- State Key Laboratory of Southwestern Chinese Medicine Resources, Department of Pharmacology, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Luchuan Yang
- Institute of traditional Chinese medicine, Sichuan College of traditional Chinese Medicine (Sichuan Second Hospital of TCM), Chengdu 610031, China
| | - Lei He
- Institute of traditional Chinese medicine, Sichuan College of traditional Chinese Medicine (Sichuan Second Hospital of TCM), Chengdu 610031, China
| | - Tao Tao
- Institute of traditional Chinese medicine, Sichuan College of traditional Chinese Medicine (Sichuan Second Hospital of TCM), Chengdu 610031, China
| | - Yanmei Wang
- Institute of traditional Chinese medicine, Sichuan College of traditional Chinese Medicine (Sichuan Second Hospital of TCM), Chengdu 610031, China.
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3
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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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4
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Simonsen S, Søgaard CK, Olsen JG, Otterlei M, Kragelund BB. The bacterial DNA sliding clamp, β-clamp: structure, interactions, dynamics and drug discovery. Cell Mol Life Sci 2024; 81:245. [PMID: 38814467 PMCID: PMC11139829 DOI: 10.1007/s00018-024-05252-w] [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: 03/14/2024] [Revised: 04/22/2024] [Accepted: 04/23/2024] [Indexed: 05/31/2024]
Abstract
DNA replication is a tightly coordinated event carried out by a multiprotein replication complex. An essential factor in the bacterial replication complex is the ring-shaped DNA sliding clamp, β-clamp, ensuring processive DNA replication and DNA repair through tethering of polymerases and DNA repair proteins to DNA. β -clamp is a hub protein with multiple interaction partners all binding through a conserved clamp binding sequence motif. Due to its central role as a DNA scaffold protein, β-clamp is an interesting target for antimicrobial drugs, yet little effort has been put into understanding the functional interactions of β-clamp. In this review, we scrutinize the β-clamp structure and dynamics, examine how its interactions with a plethora of binding partners are regulated through short linear binding motifs and discuss how contexts play into selection. We describe the dynamic process of clamp loading onto DNA and cover the recent advances in drug development targeting β-clamp. Despite decades of research in β-clamps and recent landmark structural insight, much remains undisclosed fostering an increased focus on this very central protein.
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Affiliation(s)
- Signe Simonsen
- Linderstrøm-Lang Centre for Protein Science, University of Copenhagen, Ole Maaløes Vej 5, 2200, Copenhagen N, Denmark
- Structural Biology and NMR Laboratory, University of Copenhagen, Ole Maaløes Vej 5, 2200, Copenhagen N, Denmark
| | - Caroline K Søgaard
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Johan G Olsen
- Linderstrøm-Lang Centre for Protein Science, University of Copenhagen, Ole Maaløes Vej 5, 2200, Copenhagen N, Denmark
- Structural Biology and NMR Laboratory, University of Copenhagen, Ole Maaløes Vej 5, 2200, Copenhagen N, Denmark
- Department of Biology, REPIN, University of Copenhagen, Ole Maaløes Vej 5, 2200, Copenhagen N, Denmark
| | - Marit Otterlei
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
| | - Birthe B Kragelund
- Linderstrøm-Lang Centre for Protein Science, University of Copenhagen, Ole Maaløes Vej 5, 2200, Copenhagen N, Denmark.
- Structural Biology and NMR Laboratory, University of Copenhagen, Ole Maaløes Vej 5, 2200, Copenhagen N, Denmark.
- Department of Biology, REPIN, University of Copenhagen, Ole Maaløes Vej 5, 2200, Copenhagen N, Denmark.
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He Q, Wang F, O’Donnell ME, Li H. Cryo-EM reveals a nearly complete PCNA loading process and unique features of the human alternative clamp loader CTF18-RFC. Proc Natl Acad Sci U S A 2024; 121:e2319727121. [PMID: 38669181 PMCID: PMC11067034 DOI: 10.1073/pnas.2319727121] [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: 11/10/2023] [Accepted: 03/15/2024] [Indexed: 04/28/2024] Open
Abstract
The DNA sliding clamp PCNA is a multipurpose platform for DNA polymerases and many other proteins involved in DNA metabolism. The topologically closed PCNA ring needs to be cracked open and loaded onto DNA by a clamp loader, e.g., the well-studied pentameric ATPase complex RFC (RFC1-5). The CTF18-RFC complex is an alternative clamp loader found recently to bind the leading strand DNA polymerase ε and load PCNA onto leading strand DNA, but its structure and the loading mechanism have been unknown. By cryo-EM analysis of in vitro assembled human CTF18-RFC-DNA-PCNA complex, we have captured seven loading intermediates, revealing a detailed PCNA loading mechanism onto a 3'-ss/dsDNA junction by CTF18-RFC. Interestingly, the alternative loader has evolved a highly mobile CTF18 AAA+ module likely to lower the loading activity, perhaps to avoid competition with the RFC and to limit its role to leading strand clamp loading. To compensate for the lost stability due to the mobile AAA+ module, CTF18 has evolved a unique β-hairpin motif that reaches across RFC2 to interact with RFC5, thereby stabilizing the pentameric complex. Further, we found that CTF18 also contains a separation pin to locally melt DNA from the 3'-end of the primer; this ensures its ability to load PCNA to any 3'-ss/dsDNA junction, facilitated by the binding energy of the E-plug to the major groove. Our study reveals unique structural features of the human CTF18-RFC and contributes to a broader understanding of PCNA loading by the alternative clamp loaders.
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Affiliation(s)
- Qing He
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI49503
| | - Feng Wang
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI49503
| | - Michael E. O’Donnell
- DNA Replication Laboratory, The Rockefeller University, New York, NY10065
- HHMI, The Rockefeller University, New York, NY10065
| | - Huilin Li
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI49503
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Landeck JT, Pajak J, Norman EK, Sedivy EL, Kelch BA. Differences between bacteria and eukaryotes in clamp loader mechanism, a conserved process underlying DNA replication. J Biol Chem 2024; 300:107166. [PMID: 38490435 PMCID: PMC11044049 DOI: 10.1016/j.jbc.2024.107166] [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: 01/10/2024] [Revised: 02/23/2024] [Accepted: 03/01/2024] [Indexed: 03/17/2024] Open
Abstract
Clamp loaders are pentameric ATPases that place circular sliding clamps onto DNA, where they function in DNA replication and genome integrity. The central activity of a clamp loader is the opening of the ring-shaped sliding clamp and the subsequent binding to primer-template (p/t)-junctions. The general architecture of clamp loaders is conserved across all life, suggesting that their mechanism is retained. Recent structural studies of the eukaryotic clamp loader replication factor C (RFC) revealed that it functions using a crab-claw mechanism, where clamp opening is coupled to a massive conformational change in the loader. Here we investigate the clamp loading mechanism of the Escherichia coli clamp loader at high resolution using cryo-electron microscopy. We find that the E. coli clamp loader opens the clamp using a crab-claw motion at a single pivot point, whereas the eukaryotic RFC loader uses motions distributed across the complex. Furthermore, we find clamp opening occurs in multiple steps, starting with a partly open state with a spiral conformation, and proceeding to a wide open clamp in a surprising planar geometry. Finally, our structures in the presence of p/t-junctions illustrate how the clamp closes around p/t-junctions and how the clamp loader initiates release from the loaded clamp. Our results reveal mechanistic distinctions in a macromolecular machine that is conserved across all domains of life.
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Affiliation(s)
- Jacob T Landeck
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Joshua Pajak
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Emily K Norman
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Emma L Sedivy
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Brian A Kelch
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA.
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Landeck JT, Pajak J, Norman EK, Sedivy EL, Kelch BA. Differences in clamp loader mechanism between bacteria and eukaryotes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.30.569468. [PMID: 38076975 PMCID: PMC10705477 DOI: 10.1101/2023.11.30.569468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
Clamp loaders are pentameric ATPases that place circular sliding clamps onto DNA, where they function in DNA replication and genome integrity. The central activity of a clamp loader is the opening of the ring-shaped sliding clamp, and the subsequent binding to primer-template (p/t)-junctions. The general architecture of clamp loaders is conserved across all life, suggesting that their mechanism is retained. Recent structural studies of the eukaryotic clamp loader Replication Factor C (RFC) revealed that it functions using a crab-claw mechanism, where clamp opening is coupled to a massive conformational change in the loader. Here we investigate the clamp loading mechanism of the E. coli clamp loader at high resolution using cryo-electron microscopy (cryo-EM). We find that the E. coli clamp loader opens the clamp using a crab-claw motion at a single pivot point, whereas the eukaryotic RFC loader uses motions distributed across the complex. Furthermore, we find clamp opening occurs in multiple steps, starting with a partly open state with a spiral conformation, and proceeding to a wide open clamp in a surprising planar geometry. Finally, our structures in the presence of p/t-junctions illustrate how clamp closes around p/t-junctions and how the clamp loader initiates release from the loaded clamp. Our results reveal mechanistic distinctions in a macromolecular machine that is conserved across all domains of life.
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Affiliation(s)
- Jacob T. Landeck
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester MA
| | - Joshua Pajak
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester MA
| | - Emily K. Norman
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester MA
| | - Emma L. Sedivy
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester MA
| | - Brian A. Kelch
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester MA
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8
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Schramm T, Lubrano P, Pahl V, Stadelmann A, Verhülsdonk A, Link H. Mapping temperature-sensitive mutations at a genome scale to engineer growth switches in Escherichia coli. Mol Syst Biol 2023; 19:e11596. [PMID: 37642940 PMCID: PMC10568205 DOI: 10.15252/msb.202311596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 08/14/2023] [Accepted: 08/14/2023] [Indexed: 08/31/2023] Open
Abstract
Temperature-sensitive (TS) mutants are a unique tool to perturb and engineer cellular systems. Here, we constructed a CRISPR library with 15,120 Escherichia coli mutants, each with a single amino acid change in one of 346 essential proteins. 1,269 of these mutants showed temperature-sensitive growth in a time-resolved competition assay. We reconstructed 94 TS mutants and measured their metabolism under growth arrest at 42°C using metabolomics. Metabolome changes were strong and mutant-specific, showing that metabolism of nongrowing E. coli is perturbation-dependent. For example, 24 TS mutants of metabolic enzymes overproduced the direct substrate metabolite due to a bottleneck in their associated pathway. A strain with TS homoserine kinase (ThrBF267D ) produced homoserine for 24 h, and production was tunable by temperature. Finally, we used a TS subunit of DNA polymerase III (DnaXL289Q ) to decouple growth from arginine overproduction in engineered E. coli. These results provide a strategy to identify TS mutants en masse and demonstrate their large potential to produce bacterial metabolites with nongrowing cells.
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Affiliation(s)
- Thorben Schramm
- Interfaculty Institute of Microbiology and Infection MedicineUniversity of TübingenTübingenGermany
- Cluster of Excellence “Controlling Microbes to Fight Infections”University of TübingenTübingenGermany
- Present address:
Department of Biology, Institute of Molecular Systems BiologyETH ZurichZürichSwitzerland
| | - Paul Lubrano
- Interfaculty Institute of Microbiology and Infection MedicineUniversity of TübingenTübingenGermany
- Cluster of Excellence “Controlling Microbes to Fight Infections”University of TübingenTübingenGermany
| | - Vanessa Pahl
- Interfaculty Institute of Microbiology and Infection MedicineUniversity of TübingenTübingenGermany
- Cluster of Excellence “Controlling Microbes to Fight Infections”University of TübingenTübingenGermany
| | - Amelie Stadelmann
- Interfaculty Institute of Microbiology and Infection MedicineUniversity of TübingenTübingenGermany
- Cluster of Excellence “Controlling Microbes to Fight Infections”University of TübingenTübingenGermany
| | - Andreas Verhülsdonk
- Interfaculty Institute of Microbiology and Infection MedicineUniversity of TübingenTübingenGermany
- Cluster of Excellence “Controlling Microbes to Fight Infections”University of TübingenTübingenGermany
| | - Hannes Link
- Interfaculty Institute of Microbiology and Infection MedicineUniversity of TübingenTübingenGermany
- Cluster of Excellence “Controlling Microbes to Fight Infections”University of TübingenTübingenGermany
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9
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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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10
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Phadte AS, Bhatia M, Ebert H, Abdullah H, Elrazaq EA, Komolov KE, Pluciennik A. FAN1 removes triplet repeat extrusions via a PCNA- and RFC-dependent mechanism. Proc Natl Acad Sci U S A 2023; 120:e2302103120. [PMID: 37549289 PMCID: PMC10438374 DOI: 10.1073/pnas.2302103120] [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: 02/06/2023] [Accepted: 06/22/2023] [Indexed: 08/09/2023] Open
Abstract
Human genome-wide association studies have identified FAN1 and several DNA mismatch repair (MMR) genes as modifiers of Huntington's disease age of onset. In animal models, FAN1 prevents somatic expansion of CAG triplet repeats, whereas MMR proteins promote this process. To understand the molecular basis of these opposing effects, we evaluated FAN1 nuclease function on DNA extrahelical extrusions that represent key intermediates in triplet repeat expansion. Here, we describe a strand-directed, extrusion-provoked nuclease function of FAN1 that is activated by RFC, PCNA, and ATP at physiological ionic strength. Activation of FAN1 in this manner results in DNA cleavage in the vicinity of triplet repeat extrahelical extrusions thereby leading to their removal in human cell extracts. The role of PCNA and RFC is to confer strand directionality to the FAN1 nuclease, and this reaction requires a physical interaction between PCNA and FAN1. Using cell extracts, we show that FAN1-dependent CAG extrusion removal relies on a very short patch excision-repair mechanism that competes with MutSβ-dependent MMR which is characterized by longer excision tracts. These results provide a mechanistic basis for the role of FAN1 in preventing repeat expansion and could explain the antagonistic effects of MMR and FAN1 in disease onset/progression.
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Affiliation(s)
- Ashutosh S. Phadte
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA19107
| | - Mayuri Bhatia
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA19107
| | - Hope Ebert
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA19107
| | - Haaris Abdullah
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA19107
| | - Essam Abed Elrazaq
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA19107
| | - Konstantin E. Komolov
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA19107
| | - Anna Pluciennik
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA19107
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11
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Nelson-Rigg R, Fagan SP, Jaremko WJ, Pata JD. Pre-Steady-State Kinetic Characterization of an Antibiotic-Resistant Mutant of Staphylococcus aureus DNA Polymerase PolC. Antimicrob Agents Chemother 2023; 67:e0157122. [PMID: 37222615 PMCID: PMC10269047 DOI: 10.1128/aac.01571-22] [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: 11/23/2022] [Accepted: 04/17/2023] [Indexed: 05/25/2023] Open
Abstract
The emergence and spread of antibiotic resistance in bacterial pathogens are serious and ongoing threats to public health. Since chromosome replication is essential to cell growth and pathogenesis, the essential DNA polymerases in bacteria have long been targets of antimicrobial development, although none have yet advanced to the market. Here, we use transient-state kinetic methods to characterize the inhibition of the PolC replicative DNA polymerase from Staphylococcus aureus by 2-methoxyethyl-6-(3'-ethyl-4'-methylanilino)uracil (ME-EMAU), a member of the 6-anilinouracil compounds that specifically target PolC enzymes, which are found in low-GC content Gram-positive bacteria. We find that ME-EMAU binds to S. aureus PolC with a dissociation constant of 14 nM, more than 200-fold tighter than the previously reported inhibition constant, which was determined using steady-state kinetic methods. This tight binding is driven by a very slow off rate of 0.006 s-1. We also characterized the kinetics of nucleotide incorporation by PolC containing a mutation of phenylalanine 1261 to leucine (F1261L). The F1261L mutation decreases ME-EMAU binding affinity by at least 3,500-fold but also decreases the maximal rate of nucleotide incorporation by 11.5-fold. This suggests that bacteria acquiring this mutation would be likely to replicate slowly and be unable to out-compete wild-type strains in the absence of inhibitors, reducing the likelihood of the resistant bacteria propagating and spreading resistance.
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Affiliation(s)
- Rachel Nelson-Rigg
- Wadsworth Center, New York State Department of Health, Albany, New York, USA
- Department of Biomedical Sciences, University at Albany, Albany, New York, USA
| | - Sean P. Fagan
- Wadsworth Center, New York State Department of Health, Albany, New York, USA
- Department of Biomedical Sciences, University at Albany, Albany, New York, USA
| | - William J. Jaremko
- Wadsworth Center, New York State Department of Health, Albany, New York, USA
| | - Janice D. Pata
- Wadsworth Center, New York State Department of Health, Albany, New York, USA
- Department of Biomedical Sciences, University at Albany, Albany, New York, USA
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12
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Characterization and genome analysis of Escherichia phage fBC-Eco01, isolated from wastewater in Tunisia. Arch Virol 2023; 168:44. [PMID: 36609878 PMCID: PMC9825357 DOI: 10.1007/s00705-022-05680-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 11/01/2022] [Indexed: 01/09/2023]
Abstract
The rise of antibiotic resistance in bacterial strains has led to vigorous exploration for alternative treatments. To this end, phage therapy has been revisited, and it is gaining increasing attention, as it may represent an efficient alternative for treating multiresistant pathogenic bacteria. Phage therapy is considered safe, and phages do not infect eukaryotic cells. There have been many studies investigating phage-host bacteria interactions and the ability of phages to target specific hosts. Escherichia coli is the causative agent of a multitude of infections, ranging from urinary tract infections to sepsis, with growing antibiotic resistance. In this study, we characterized the Escherichia phage fBC-Eco01, which was isolated from a water sample collected at Oued, Tunis. Electron microscopy showed that fBC-Eco01 phage particles have siphovirus morphology, with an icosahedral head of 61 ± 3 nm in diameter and a non-contractile tail of 94 ± 2 nm in length and 12 ± 0.9 nm in width. The genome of fBC-Eco01 is a linear double-stranded DNA of 43.466 bp with a GC content of 50.4%. Comparison to databases allowed annotation of the functions to 39 of the 78 predicted gene products. A single-step growth curve revealed that fBC-Eco01 has a latent period of 30 minutes and a burst size of 175 plaque-forming units (PFU) per infected cell. Genomic analysis indicated that fBC-Eco01 is a member of the subfamily Guernseyvirinae. It is most closely related to a group of phages of the genus Kagunavirus that infect Enterobacter, Raoultella, and Escherichia strains.
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13
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Mulye M, Singh MI, Jain V. From Processivity to Genome Maintenance: The Many Roles of Sliding Clamps. Genes (Basel) 2022; 13:2058. [PMID: 36360296 PMCID: PMC9690074 DOI: 10.3390/genes13112058] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 11/03/2022] [Accepted: 11/04/2022] [Indexed: 07/30/2023] Open
Abstract
Sliding clamps play a pivotal role in the process of replication by increasing the processivity of the replicative polymerase. They also serve as an interacting platform for a plethora of other proteins, which have an important role in other DNA metabolic processes, including DNA repair. In other words, clamps have evolved, as has been correctly referred to, into a mobile "tool-belt" on the DNA, and provide a platform for several proteins that are involved in maintaining genome integrity. Because of the central role played by the sliding clamp in various processes, its study becomes essential and relevant in understanding these processes and exploring the protein as an important drug target. In this review, we provide an updated report on the functioning, interactions, and moonlighting roles of the sliding clamps in various organisms and its utilization as a drug target.
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Affiliation(s)
- Meenakshi Mulye
- Correspondence: (M.M.); (V.J.); Tel.: +91-755-269-1425 (V.J.); Fax: +91-755-269-2392 (V.J.)
| | | | - Vikas Jain
- Correspondence: (M.M.); (V.J.); Tel.: +91-755-269-1425 (V.J.); Fax: +91-755-269-2392 (V.J.)
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14
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MutS recognition of mismatches within primed DNA replication intermediates. DNA Repair (Amst) 2022; 119:103392. [PMID: 36095926 DOI: 10.1016/j.dnarep.2022.103392] [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: 02/17/2022] [Revised: 08/23/2022] [Accepted: 08/25/2022] [Indexed: 11/24/2022]
Abstract
MutS initiates mismatch repair by recognizing mismatches in newly replicated DNA. Specific interactions between MutS and mismatches within double-stranded DNA promote ADP-ATP exchange and a conformational change into a sliding clamp. Here, we demonstrated that MutS from Pseudomonas aeruginosa associates with primed DNA replication intermediates. The predicted structure of this MutS-DNA complex revealed a new DNA binding site, in which Asn 279 and Arg 272 appeared to directly interact with the 3'-OH terminus of primed DNA. Mutation of these residues resulted in a noticeable defect in the interaction of MutS with primed DNA substrates. Remarkably, MutS interaction with a mismatch within primed DNA induced a compaction of the protein structure and impaired the formation of an ATP-bound sliding clamp. Our findings reveal a novel DNA binding mode, conformational change and intramolecular signaling for MutS recognition of mismatches within primed DNA structures.
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15
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Chang S, Thrall ES, Laureti L, Piatt SC, Pagès V, Loparo JJ. Compartmentalization of the replication fork by single-stranded DNA-binding protein regulates translesion synthesis. Nat Struct Mol Biol 2022; 29:932-941. [PMID: 36127468 PMCID: PMC9509481 DOI: 10.1038/s41594-022-00827-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 07/28/2022] [Indexed: 11/09/2022]
Abstract
Processivity clamps tether DNA polymerases to DNA, allowing their access to the primer-template junction. In addition to DNA replication, DNA polymerases also participate in various genome maintenance activities, including translesion synthesis (TLS). However, owing to the error-prone nature of TLS polymerases, their association with clamps must be tightly regulated. Here we show that fork-associated ssDNA-binding protein (SSB) selectively enriches the bacterial TLS polymerase Pol IV at stalled replication forks. This enrichment enables Pol IV to associate with the processivity clamp and is required for TLS on both the leading and lagging strands. In contrast, clamp-interacting proteins (CLIPs) lacking SSB binding are spatially segregated from the replication fork, minimally interfering with Pol IV-mediated TLS. We propose that stalling-dependent structural changes within clusters of fork-associated SSB establish hierarchical access to the processivity clamp. This mechanism prioritizes a subset of CLIPs with SSB-binding activity and facilitates their exchange at the replication fork.
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Affiliation(s)
- Seungwoo Chang
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Elizabeth S Thrall
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
- Department of Chemistry, Fordham University, New York City, NY, USA
| | - Luisa Laureti
- CRCM (Cancer Research Center of Marseille): Team DNA Damage and Genome Instability, Aix-Marseille University, CNRS, INSERM, Institut Paoli-Calmettes, Marseille, France
| | - Sadie C Piatt
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
- Harvard Graduate Program in Biophysics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Vincent Pagès
- CRCM (Cancer Research Center of Marseille): Team DNA Damage and Genome Instability, Aix-Marseille University, CNRS, INSERM, Institut Paoli-Calmettes, Marseille, France
| | - Joseph J Loparo
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
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16
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Mazal H, Wieser FF, Sandoghdar V. Deciphering a hexameric protein complex with Angstrom optical resolution. eLife 2022; 11:76308. [PMID: 35616526 PMCID: PMC9142145 DOI: 10.7554/elife.76308] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 05/12/2022] [Indexed: 12/24/2022] Open
Abstract
Cryogenic optical localization in three dimensions (COLD) was recently shown to resolve up to four binding sites on a single protein. However, because COLD relies on intensity fluctuations that result from the blinking behavior of fluorophores, it is limited to cases where individual emitters show different brightness. This significantly lowers the measurement yield. To extend the number of resolved sites as well as the measurement yield, we employ partial labeling and combine it with polarization encoding in order to identify single fluorophores during their stochastic blinking. We then use a particle classification scheme to identify and resolve heterogenous subsets and combine them to reconstruct the three-dimensional arrangement of large molecular complexes. We showcase this method (polarCOLD) by resolving the trimer arrangement of proliferating cell nuclear antigen (PCNA) and six different sites of the hexamer protein Caseinolytic Peptidase B (ClpB) of Thermus thermophilus in its quaternary structure, both with Angstrom resolution. The combination of polarCOLD and single-particle cryogenic electron microscopy (cryoEM) promises to provide crucial insight into intrinsic heterogeneities of biomolecular structures. Furthermore, our approach is fully compatible with fluorescent protein labeling and can, thus, be used in a wide range of studies in cell and membrane biology.
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Affiliation(s)
- Hisham Mazal
- Max Planck Institute for the Science of Light, Erlangen, Germany.,Max-Planck-Zentrum für Physik und Medizin, Erlangen, Germany
| | - Franz-Ferdinand Wieser
- Max Planck Institute for the Science of Light, Erlangen, Germany.,Max-Planck-Zentrum für Physik und Medizin, Erlangen, Germany.,Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
| | - Vahid Sandoghdar
- Max Planck Institute for the Science of Light, Erlangen, Germany.,Max-Planck-Zentrum für Physik und Medizin, Erlangen, Germany.,Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
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17
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Monsarrat C, Compain G, André C, Engilberge S, Martiel I, Oliéric V, Wolff P, Brillet K, Landolfo M, Silva da Veiga C, Wagner J, Guichard G, Burnouf DY. Iterative Structure-Based Optimization of Short Peptides Targeting the Bacterial Sliding Clamp. J Med Chem 2021; 64:17063-17078. [PMID: 34806883 DOI: 10.1021/acs.jmedchem.1c00918] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The bacterial DNA sliding clamp (SC), or replication processivity factor, is a promising target for the development of novel antibiotics. We report a structure-activity relationship study of a new series of peptides interacting within the Escherichia coli SC (EcSC) binding pocket. Various modifications were explored including N-alkylation of the peptide bonds, extension of the N-terminal moiety, and introduction of hydrophobic and constrained residues at the C-terminus. In each category, single modifications were identified that increased affinity to EcSC. A combination of such modifications yielded in several cases to a substantially increased affinity compared to the parent peptides with Kd in the range of 30-80 nM. X-ray structure analysis of 11 peptide/EcSC co-crystals revealed new interactions at the peptide-protein interface (i.e., stacking interactions, hydrogen bonds, and hydrophobic contacts) that can account for the improved binding. Several compounds among the best binders were also found to be more effective in inhibiting SC-dependent DNA synthesis.
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Affiliation(s)
- Clément Monsarrat
- Université de Bordeaux, CNRS, Bordeaux INP, CBMN, UMR 5248, Institut Européen de Chimie et Biologie, 2 rue Robert Escarpit, F-33607 Pessac, France
| | - Guillaume Compain
- Université de Bordeaux, CNRS, Bordeaux INP, CBMN, UMR 5248, Institut Européen de Chimie et Biologie, 2 rue Robert Escarpit, F-33607 Pessac, France
| | - Christophe André
- Université de Bordeaux, CNRS, Bordeaux INP, CBMN, UMR 5248, Institut Européen de Chimie et Biologie, 2 rue Robert Escarpit, F-33607 Pessac, France
| | - Sylvain Engilberge
- Swiss Light Source (SLS), Paul Scherrer Institute (PSI), Forschungstrasse 111, 5232 Villigen-PSI, Switzerland
| | - Isabelle Martiel
- Swiss Light Source (SLS), Paul Scherrer Institute (PSI), Forschungstrasse 111, 5232 Villigen-PSI, Switzerland
| | - Vincent Oliéric
- Swiss Light Source (SLS), Paul Scherrer Institute (PSI), Forschungstrasse 111, 5232 Villigen-PSI, Switzerland
| | - Philippe Wolff
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, Institut de Biologie Moléculaire et Cellulaire du CNRS, 2 rue Conrad Roentgen, F-67000 Strasbourg, France
| | - Karl Brillet
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, Institut de Biologie Moléculaire et Cellulaire du CNRS, 2 rue Conrad Roentgen, F-67000 Strasbourg, France
| | - Marie Landolfo
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, Institut de Biologie Moléculaire et Cellulaire du CNRS, 2 rue Conrad Roentgen, F-67000 Strasbourg, France
| | - Cyrielle Silva da Veiga
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, Institut de Biologie Moléculaire et Cellulaire du CNRS, 2 rue Conrad Roentgen, F-67000 Strasbourg, France
| | - Jérôme Wagner
- Biotechnologie et Signalisation Cellulaire, UMR 7242 CNRS/Université de Strasbourg, ESBS, 300 Boulevard Sébastien Brant, 67412 Illkirch, France
| | - Gilles Guichard
- Université de Bordeaux, CNRS, Bordeaux INP, CBMN, UMR 5248, Institut Européen de Chimie et Biologie, 2 rue Robert Escarpit, F-33607 Pessac, France
| | - Dominique Y Burnouf
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, Institut de Biologie Moléculaire et Cellulaire du CNRS, 2 rue Conrad Roentgen, F-67000 Strasbourg, France
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18
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Abstract
Herpesviruses comprise a family of DNA viruses that cause a variety of human and veterinary diseases. During productive infection, mammalian, avian, and reptilian herpesviruses replicate their genomes using a set of conserved viral proteins that include a two subunit DNA polymerase. This enzyme is both a model system for family B DNA polymerases and a target for inhibition by antiviral drugs. This chapter reviews the structure, function, and mechanisms of the polymerase of herpes simplex viruses 1 and 2 (HSV), with only occasional mention of polymerases of other herpesviruses such as human cytomegalovirus (HCMV). Antiviral polymerase inhibitors have had the most success against HSV and HCMV. Detailed structural information regarding HSV DNA polymerase is available, as is much functional information regarding the activities of the catalytic subunit (Pol), which include a DNA polymerization activity that can utilize both DNA and RNA primers, a 3'-5' exonuclease activity, and other activities in DNA synthesis and repair and in pathogenesis, including some remaining to be biochemically defined. Similarly, much is known regarding the accessory subunit, which both resembles and differs from sliding clamp processivity factors such as PCNA, and the interactions of this subunit with Pol and DNA. Both subunits contribute to replication fidelity (or lack thereof). The availability of both pharmacologic and genetic tools not only enabled the initial identification of Pol and the pol gene, but has also helped dissect their functions. Nevertheless, important questions remain for this long-studied enzyme, which is still an attractive target for new drug discovery.
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19
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Lata K, Vishwakarma J, Kumar S, Khanam T, Ramachandran R. Mycobacterium tuberculosis Endonuclease VIII 2 (Nei2) forms a prereplicative BER complex with DnaN: Identification, characterization, and disruption of complex formation. Mol Microbiol 2021; 117:320-333. [PMID: 34820919 DOI: 10.1111/mmi.14848] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 11/18/2021] [Accepted: 11/19/2021] [Indexed: 12/12/2022]
Abstract
Mycobacterium tuberculosis Nei2 (Rv3297) is a BER glycosylase that removes oxidized base lesions from ssDNA and replication fork-mimicking substrates. We show that Endonuclease VIII 2 (Nei2) forms a BER complex with the β-clamp (DnaN, Rv0002) with a KD of 170 nM. The Nei2-β-clamp interactions enhance Nei2's activities up to several folds. SEC analysis shows that one molecule of Nei2 binds to a single β-clamp dimer. Nei2 interacts with subsites I and II of the β-clamp via a noncanonical 223 QGCRRCGTLIAY239 Clamp Interacting Protein (CIP) motif in the C-terminal zinc-finger domain, which was previously shown by us to be dispensable for intrinsic Nei2 activity. The 12-mer peptide alone exhibited a KD of 10.28 nM, suggesting that the motif is a key mediator of Nei2-β-clamp interactions. Finally, we identified inhibitors of Nei2-β-clamp interactions using rational methods, in vitro disruption, and SPR assays after querying a database of natural products. We found that Tubulosine, Fumitremorgin C, Toyocamycin, and Aleuritic acid exhibit IC50 values of 94.47, 83.49, 109.7, and 71.49 µM, respectively. They act by disrupting Nei2-β-clamp interactions and do not affect intrinsic Nei2 activity. Among other things, the present study gives insights into the role of Nei2 in bacterial prereplicative BER.
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Affiliation(s)
- Kiran Lata
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Lucknow, India
| | - Jyoti Vishwakarma
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Lucknow, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Sanjay Kumar
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Lucknow, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Taran Khanam
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Lucknow, India
| | - Ravishankar Ramachandran
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Lucknow, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
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20
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Liu B, Li S, Liu Y, Chen H, Hu Z, Wang Z, Zhao Y, Zhang L, Ma B, Wang H, Matthews S, Wang Y, Zhang K. Bacteriophage Twort protein Gp168 is a β-clamp inhibitor by occupying the DNA sliding channel. Nucleic Acids Res 2021; 49:11367-11378. [PMID: 34614154 PMCID: PMC8565349 DOI: 10.1093/nar/gkab875] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 09/13/2021] [Accepted: 09/16/2021] [Indexed: 11/22/2022] Open
Abstract
Bacterial chromosome replication is mainly catalyzed by DNA polymerase III, whose beta subunits enable rapid processive DNA replication. Enabled by the clamp-loading complex, the two beta subunits form a ring-like clamp around DNA and keep the polymerase sliding along. Given the essential role of β-clamp, its inhibitors have been explored for antibacterial purposes. Similarly, β-clamp is an ideal target for bacteriophages to shut off host DNA synthesis during host takeover. The Gp168 protein of phage Twort is such an example, which binds to the β-clamp of Staphylococcus aureus and prevents it from loading onto DNA causing replication arrest. Here, we report a cryo-EM structure of the clamp–Gp168 complex at 3.2-Å resolution. In the structure of the complex, the Gp168 dimer occupies the DNA sliding channel of β-clamp and blocks its loading onto DNA, which represents a new inhibitory mechanism against β-clamp function. Interestingly, the key residues responsible for this interaction on the β-clamp are well conserved among bacteria. We therefore demonstrate that Gp168 is potentially a cross-species β-clamp inhibitor, as it forms complex with the Bacillus subtilis β-clamp. Our findings reveal an alternative mechanism for bacteriophages to inhibit β-clamp and provide a new strategy to combat bacterial drug resistance.
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Affiliation(s)
- Bing Liu
- BioBank, The First Affiliated Hospital of Xi'an Jiaotong University, Shaanxi 710061, China.,Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Shanshan Li
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale and Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China
| | - Yang Liu
- BioBank, The First Affiliated Hospital of Xi'an Jiaotong University, Shaanxi 710061, China
| | - Huan Chen
- BioBank, The First Affiliated Hospital of Xi'an Jiaotong University, Shaanxi 710061, China
| | - Zhenyue Hu
- BioBank, The First Affiliated Hospital of Xi'an Jiaotong University, Shaanxi 710061, China
| | - Zhihao Wang
- BioBank, The First Affiliated Hospital of Xi'an Jiaotong University, Shaanxi 710061, China.,Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Yimin Zhao
- MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an 710049, China
| | - Lei Zhang
- MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an 710049, China
| | - Biyun Ma
- BioBank, The First Affiliated Hospital of Xi'an Jiaotong University, Shaanxi 710061, China
| | - Hongliang Wang
- Department of Pathogen Biology and Immunology, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, China
| | - Steve Matthews
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Yawen Wang
- BioBank, The First Affiliated Hospital of Xi'an Jiaotong University, Shaanxi 710061, China
| | - Kaiming Zhang
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale and Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China
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21
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Elevated Levels of the Escherichia coli nrdAB-Encoded Ribonucleotide Reductase Counteract the Toxicity Caused by an Increased Abundance of the β Clamp. J Bacteriol 2021; 203:e0030421. [PMID: 34543109 DOI: 10.1128/jb.00304-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] 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. A mutant clamp (βE202K bearing a glutamic acid-to-lysine substitution at residue 202) binds to DNA polymerase III (Pol III) with higher affinity than the wild-type clamp, suggesting that its failure to impede growth is independent of its ability to sequester Pol III away from the replication fork. Our results demonstrate that the dnaNE202K strain underinitiates DNA replication due to insufficient levels of DnaA-ATP and expresses several DnaA-regulated genes at altered levels, including nrdAB, that encode the class 1a ribonucleotide reductase (RNR). Elevated expression of nrdAB was dependent on hda function. As the β clamp-Hda complex regulates the activity of DnaA by stimulating its intrinsic ATPase activity, this finding suggests that the dnaNE202K allele supports an elevated level of Hda activity in vivo compared with the wild-type strain. In contrast, using an in vitro assay reconstituted with purified components the βE202K and wild-type clamp proteins supported comparable levels of Hda activity. Nevertheless, co-overexpression of the nrdAB-encoded RNR relieved the growth defect caused by elevated levels of the β clamp. These results support a model in which increased cellular levels of DNA precursors relieve the ability of elevated β clamp levels to impede growth and suggest either that multiple effects stemming from the dnaNE202K mutation contribute to elevated nrdAB levels or that Hda plays a noncatalytic role in regulating DnaA-ATP by sequestering it to reduce its availability. IMPORTANCE DnaA bound to ATP acts in initiation of DNA replication and regulates the expression of several genes whose products act in DNA metabolism. The state of the ATP bound to DnaA is regulated in part by the β clamp-Hda complex. The dnaNE202K allele was identified by virtue of its inability to impede growth when expressed ≥10-fold higher than chromosomally expressed levels. While the dnaNE202K strain exhibits several phenotypes consistent with heightened Hda activity, the wild-type and βE202K clamp proteins support equivalent levels of Hda activity in vitro. Taken together, these results suggest that βE202K-Hda plays a noncatalytic role in regulating DnaA-ATP. This, as well as alternative models, is discussed.
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22
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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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23
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Strand discrimination in DNA mismatch repair. DNA Repair (Amst) 2021; 105:103161. [PMID: 34171627 DOI: 10.1016/j.dnarep.2021.103161] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 06/15/2021] [Accepted: 06/16/2021] [Indexed: 11/24/2022]
Abstract
DNA mismatch repair (MMR) corrects non-Watson-Crick basepairs generated by replication errors, recombination intermediates, and some forms of chemical damage to DNA. In MutS and MutL homolog-dependent MMR, damaged bases do not identify the error-containing daughter strand that must be excised and resynthesized. In organisms like Escherichia coli that use methyl-directed MMR, transient undermethylation identifies the daughter strand. For other organisms, growing in vitro and in vivo evidence suggest that strand discrimination is mediated by DNA replication-associated daughter strand nicks that direct asymmetric loading of the replicative clamp (the β-clamp in bacteria and the proliferating cell nuclear antigen, PCNA, in eukaryotes). Structural modeling suggests that replicative clamps mediate strand specificity either through the ability of MutL homologs to recognize the fixed orientation of the daughter strand relative to one face of the replicative clamps or through parental strand-specific diffusion of replicative clamps on DNA, which places the daughter strand in the MutL homolog endonuclease active site. Finally, identification of bacteria that appear to lack strand discrimination mediated by a replicative clamp and a pre-existing nick suggest that other strand discrimination mechanisms exist or that these organisms perform MMR by generating a double-stranded DNA break intermediate, which may be analogous to NucS-mediated MMR.
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24
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Nobile MS, Fontana F, Manzoni L, Cazzaniga P, Mauri G, Saracino GAA, Besozzi D, Gelain F. HyperBeta: characterizing the structural dynamics of proteins and self-assembling peptides. Sci Rep 2021; 11:7783. [PMID: 33833280 PMCID: PMC8032683 DOI: 10.1038/s41598-021-87087-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 03/17/2021] [Indexed: 11/10/2022] Open
Abstract
Self-assembling processes are ubiquitous phenomena that drive the organization and the hierarchical formation of complex molecular systems. The investigation of assembling dynamics, emerging from the interactions among biomolecules like amino-acids and polypeptides, is fundamental to determine how a mixture of simple objects can yield a complex structure at the nano-scale level. In this paper we present HyperBeta, a novel open-source software that exploits an innovative algorithm based on hyper-graphs to efficiently identify and graphically represent the dynamics of \documentclass[12pt]{minimal}
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\begin{document}$$\beta$$\end{document}β-sheets formation. Differently from the existing tools, HyperBeta directly manipulates data generated by means of coarse-grained molecular dynamics simulation tools (GROMACS), performed using the MARTINI force field. Coarse-grained molecular structures are visualized using HyperBeta ’s proprietary real-time high-quality 3D engine, which provides a plethora of analysis tools and statistical information, controlled by means of an intuitive event-based graphical user interface. The high-quality renderer relies on a variety of visual cues to improve the readability and interpretability of distance and depth relationships between peptides. We show that HyperBeta is able to track the \documentclass[12pt]{minimal}
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\begin{document}$$\beta$$\end{document}β-sheets formation in coarse-grained molecular dynamics simulations, and provides a completely new and efficient mean for the investigation of the kinetics of these nano-structures. HyperBeta will therefore facilitate biotechnological and medical research where these structural elements play a crucial role, such as the development of novel high-performance biomaterials in tissue engineering, or a better comprehension of the molecular mechanisms at the basis of complex pathologies like Alzheimer’s disease.
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Affiliation(s)
- Marco S Nobile
- Department of Industrial Engineering and Innovation Sciences, Eindhoven University of Technology, Eindhoven, The Netherlands.,Department of Informatics, Systems and Communication, University of Milano-Bicocca, Milan, Italy.,SYSBIO/ISBE.IT Centre of Systems Biology, Milan, Italy.,Bicocca Bioinformatics, Biostatistics and Bioimaging Centre (B4), Monza, Italy
| | - Federico Fontana
- Fondazione IRCCS Casa Sollievo della Sofferenza, Unità Ingegneria Tissutale, Viale Cappuccini 1, San Giovanni Rotondo, 71013, Foggia, Italy
| | - Luca Manzoni
- Department of Mathematics and Geosciences, University of Trieste, Trieste, Italy
| | - Paolo Cazzaniga
- SYSBIO/ISBE.IT Centre of Systems Biology, Milan, Italy.,Bicocca Bioinformatics, Biostatistics and Bioimaging Centre (B4), Monza, Italy.,Department of Human and Social Sciences, University of Bergamo, Bergamo, Italy
| | - Giancarlo Mauri
- Department of Informatics, Systems and Communication, University of Milano-Bicocca, Milan, Italy.,SYSBIO/ISBE.IT Centre of Systems Biology, Milan, Italy.,Bicocca Bioinformatics, Biostatistics and Bioimaging Centre (B4), Monza, Italy
| | - Gloria A A Saracino
- Center for Nanomedicine and Tissue Engineering (CNTE), A.S.S.T. Grande Ospedale Metropolitano Niguarda, Piazza dell'Ospedale Maggiore 3, 20162, Milan, Italy
| | - Daniela Besozzi
- Department of Informatics, Systems and Communication, University of Milano-Bicocca, Milan, Italy. .,SYSBIO/ISBE.IT Centre of Systems Biology, Milan, Italy. .,Bicocca Bioinformatics, Biostatistics and Bioimaging Centre (B4), Monza, Italy.
| | - Fabrizio Gelain
- Fondazione IRCCS Casa Sollievo della Sofferenza, Unità Ingegneria Tissutale, Viale Cappuccini 1, San Giovanni Rotondo, 71013, Foggia, Italy. .,Center for Nanomedicine and Tissue Engineering (CNTE), A.S.S.T. Grande Ospedale Metropolitano Niguarda, Piazza dell'Ospedale Maggiore 3, 20162, Milan, Italy.
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25
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Li H, Zheng F, O'Donnell M. Water skating: How polymerase sliding clamps move on DNA. FEBS J 2021; 288:7256-7262. [PMID: 33523561 DOI: 10.1111/febs.15740] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 01/19/2021] [Accepted: 01/24/2021] [Indexed: 11/30/2022]
Abstract
Polymerase sliding clamps are ring-shaped proteins that encircle duplex DNA and hold polymerases to DNA for high processivity during synthesis. The crystal structure of clamp-DNA complex reveals that the DNA is highly tilted through the clamp with extensive interaction with the clamp inner surface. In contrast to the tilted clamp-DNA interaction without DNA polymerases, recent structures of replicative polymerases of bacteria, eukaryotes, and archaea that are bound to the clamp and DNA show that the polymerase positions DNA straight through the clamp without direct protein-DNA contacts. Instead, the clamp-to-DNA interaction is mediated by one or two layers of water. Hence, clamps 'water skate' on DNA during function with replicative polymerases from all domains of life, providing a nearly frictionless bearing for fast and processive DNA synthesis.
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Affiliation(s)
- Huilin Li
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, USA
| | - Fengwei Zheng
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, USA
| | - Mike O'Donnell
- DNA Replication Laboratory, The Rockefeller University, New York, NY, USA.,HHMI, The Rockefeller University, New York, NY, USA
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26
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Structure of eukaryotic DNA polymerase δ bound to the PCNA clamp while encircling DNA. Proc Natl Acad Sci U S A 2020; 117:30344-30353. [PMID: 33203675 PMCID: PMC7720213 DOI: 10.1073/pnas.2017637117] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The structure of the eukaryotic chromosomal replicase, DNA polymerase (Pol) δ, was determined in complex with its cognate proliferating cell nuclear antigen (PCNA) sliding clamp on primed DNA. The results show that the Pol3 catalytic subunit binds atop the PCNA ring, and the two regulatory subunits of Pol δ, Pol31, and Pol32, are positioned off to the side of the Pol3 clamp. The catalytic Pol3 binds DNA and PCNA such as to thread the DNA straight through the circular PCNA clamp. Considering the large diameter of the PCNA clamp, there is room for water between DNA and the inner walls of PCNA, indicating the clamp “waterskates” on DNA during function with polymerase. The DNA polymerase (Pol) δ of Saccharomyces cerevisiae (S.c.) is composed of the catalytic subunit Pol3 along with two regulatory subunits, Pol31 and Pol32. Pol δ binds to proliferating cell nuclear antigen (PCNA) and functions in genome replication, repair, and recombination. Unique among DNA polymerases, the Pol3 catalytic subunit contains a 4Fe-4S cluster that may sense the cellular redox state. Here we report the 3.2-Å cryo-EM structure of S.c. Pol δ in complex with primed DNA, an incoming ddTTP, and the PCNA clamp. Unexpectedly, Pol δ binds only one subunit of the PCNA trimer. This singular yet extensive interaction holds DNA such that the 2-nm-wide DNA threads through the center of the 3-nm interior channel of the clamp without directly contacting the protein. Thus, a water-mediated clamp and DNA interface enables the PCNA clamp to “waterskate” along the duplex with minimum drag. Pol31 and Pol32 are positioned off to the side of the catalytic Pol3-PCNA-DNA axis. We show here that Pol31-Pol32 binds single-stranded DNA that we propose underlies polymerase recycling during lagging strand synthesis, in analogy to Escherichia coli replicase. Interestingly, the 4Fe-4S cluster in the C-terminal CysB domain of Pol3 forms the central interface to Pol31-Pol32, and this strategic location may explain the regulation of the oxidation state on Pol δ activity, possibly useful during cellular oxidative stress. Importantly, human cancer and other disease mutations map to nearly every domain of Pol3, suggesting that all aspects of Pol δ replication are important to human health and disease.
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27
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Dodd T, Botto M, Paul F, Fernandez-Leiro R, Lamers MH, Ivanov I. Polymerization and editing modes of a high-fidelity DNA polymerase are linked by a well-defined path. Nat Commun 2020; 11:5379. [PMID: 33097731 PMCID: PMC7584608 DOI: 10.1038/s41467-020-19165-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Accepted: 10/02/2020] [Indexed: 12/27/2022] Open
Abstract
Proofreading by replicative DNA polymerases is a fundamental mechanism ensuring DNA replication fidelity. In proofreading, mis-incorporated nucleotides are excised through the 3'-5' exonuclease activity of the DNA polymerase holoenzyme. The exonuclease site is distal from the polymerization site, imposing stringent structural and kinetic requirements for efficient primer strand transfer. Yet, the molecular mechanism of this transfer is not known. Here we employ molecular simulations using recent cryo-EM structures and biochemical analyses to delineate an optimal free energy path connecting the polymerization and exonuclease states of E. coli replicative DNA polymerase Pol III. We identify structures for all intermediates, in which the transitioning primer strand is stabilized by conserved Pol III residues along the fingers, thumb and exonuclease domains. We demonstrate switching kinetics on a tens of milliseconds timescale and unveil a complete pol-to-exo switching mechanism, validated by targeted mutational experiments.
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Affiliation(s)
- Thomas Dodd
- Department of Chemistry, Georgia State University, Atlanta, GA, USA
- Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, USA
| | - Margherita Botto
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Fabian Paul
- Department of Biochemistry & Molecular Biology, University of Chicago, Chicago, IL, USA
| | | | - Meindert H Lamers
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, The Netherlands.
| | - Ivaylo Ivanov
- Department of Chemistry, Georgia State University, Atlanta, GA, USA.
- Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, USA.
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28
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Reply to: "Does PCNA diffusion on DNA follow a rotation-coupled translation mechanism?". Nat Commun 2020; 11:4999. [PMID: 33020489 PMCID: PMC7536410 DOI: 10.1038/s41467-020-18856-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 09/17/2020] [Indexed: 11/08/2022] Open
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29
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Does PCNA diffusion on DNA follow a rotation-coupled translation mechanism? Nat Commun 2020; 11:5000. [PMID: 33020481 PMCID: PMC7536400 DOI: 10.1038/s41467-020-18855-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 06/29/2020] [Indexed: 01/25/2023] Open
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30
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Wu Y, Jaremko WJ, Wilson RC, Pata JD. Heterotrimeric PCNA increases the activity and fidelity of Dbh, a Y-family translesion DNA polymerase prone to creating single-base deletion mutations. DNA Repair (Amst) 2020; 96:102967. [PMID: 32961405 DOI: 10.1016/j.dnarep.2020.102967] [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: 06/10/2020] [Revised: 08/18/2020] [Accepted: 08/31/2020] [Indexed: 11/15/2022]
Abstract
Dbh is a Y-family translesion DNA polymerase from Sulfolobus acidocaldarius, an archaeal species that grows in harsh environmental conditions. Biochemically, Dbh displays a distinctive mutational profile, creating single-base deletion mutations at extraordinarily high frequencies (up to 50 %) in specific repeat sequences. In cells, however, Dbh does not appear to contribute significantly to spontaneous frameshifts in these same sequence contexts. This suggests that either the error-prone DNA synthesis activity of Dbh is reduced in vivo and/or Dbh is restricted from replicating these sequences. Here, we test the hypothesis that the propensity for Dbh to make single base deletion mutations is reduced through interaction with the S. acidocaldarius heterotrimeric sliding clamp processivity factor, PCNA-123. We first confirm that Dbh physically interacts with PCNA-123, with the interaction requiring both the PCNA-1 subunit and the C-terminal 10 amino acids of Dbh, which contain a predicted PCNA-interaction peptide (PIP) motif. This interaction stimulates the polymerase activity of Dbh, even on short, linear primer-template DNA, by increasing the rate of nucleotide incorporation. This stimulation requires an intact PCNA-123 heterotrimer and a DNA duplex length of at least 18 basepairs, the minimal length predicted from structural data to bind to both the polymerase and the clamp. Finally, we find that PCNA-123 increases the fidelity of Dbh on a single-base deletion hotspot sequence 3-fold by promoting an increase in the rate of correct, but not incorrect, nucleotide addition and propose that PCNA-123 induces Dbh to adopt a more active conformation that is less prone to creating deletions during DNA synthesis.
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Affiliation(s)
- Yifeng Wu
- Wadsworth Center, New York State Department of Health, Albany, NY, United States; Department of Biomedical Sciences, University at Albany, Albany, NY, United States
| | - William J Jaremko
- Wadsworth Center, New York State Department of Health, Albany, NY, United States
| | - Ryan C Wilson
- Wadsworth Center, New York State Department of Health, Albany, NY, United States
| | - Janice D Pata
- Wadsworth Center, New York State Department of Health, Albany, NY, United States; Department of Biomedical Sciences, University at Albany, Albany, NY, United States.
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31
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You S, Lee HG, Kim K, Yoo J. Improved Parameterization of Protein-DNA Interactions for Molecular Dynamics Simulations of PCNA Diffusion on DNA. J Chem Theory Comput 2020; 16:4006-4013. [PMID: 32543861 DOI: 10.1021/acs.jctc.0c00241] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
As the field of molecular dynamics simulation utilizing the force fields is moving toward more complex systems, the accuracy of intermolecular interactions has become a central issue of the field. Here, we quantitatively evaluate the accuracy of the protein-DNA interactions in AMBER and CHARMM force fields by comparing experimental and simulated diffusion coefficients of proliferating cell nuclear antigen. We find that both force fields underestimate diffusion coefficients by at least an order of magnitude because the interactions between basic amino acids and DNA phosphate groups are too attractive. Then, we propose Lennard-Jones parameters optimized using the experimental osmotic pressure data of model chemicals, by using which one can reproduce the experimental diffusion coefficients. Newly optimized parameters will have a broad impact on general protein-DNA interactions.
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Affiliation(s)
- Seonju You
- Department of Chemistry, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Hong-Guen Lee
- Division of Advanced Materials Science, Pohang University of Science and Technology, Pohang 37673, Republic of Korea.,Center for Self-Assembly and Complexity, Institute for Basic Science, Pohang 37673, Republic of Korea
| | - Kimoon Kim
- Department of Chemistry, Pohang University of Science and Technology, Pohang 37673, Republic of Korea.,Center for Self-Assembly and Complexity, Institute for Basic Science, Pohang 37673, Republic of Korea
| | - Jejoong Yoo
- Center for Self-Assembly and Complexity, Institute for Basic Science, Pohang 37673, Republic of Korea.,Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
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32
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Structure of the polymerase ε holoenzyme and atomic model of the leading strand replisome. Nat Commun 2020; 11:3156. [PMID: 32572031 PMCID: PMC7308368 DOI: 10.1038/s41467-020-16910-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 06/02/2020] [Indexed: 01/01/2023] Open
Abstract
The eukaryotic leading strand DNA polymerase (Pol) ε contains 4 subunits, Pol2, Dpb2, Dpb3 and Dpb4. Pol2 is a fusion of two B-family Pols; the N-terminal Pol module is catalytic and the C-terminal Pol module is non-catalytic. Despite extensive efforts, there is no atomic structure for Pol ε holoenzyme, critical to understanding how DNA synthesis is coordinated with unwinding and the DNA path through the CMG helicase-Pol ε-PCNA clamp. We show here a 3.5-Å cryo-EM structure of yeast Pol ε revealing that the Dpb3–Dpb4 subunits bridge the two DNA Pol modules of Pol2, holding them rigid. This information enabled an atomic model of the leading strand replisome. Interestingly, the model suggests that an OB fold in Dbp2 directs leading ssDNA from CMG to the Pol ε active site. These results complete the DNA path from entry of parental DNA into CMG to exit of daughter DNA from PCNA. DNA polymerase epsilon (Pol ε) is responsible for leading strand synthesis during DNA replication. Here the authors use Cryo-EM to describe the architecture of the Pol ε holoenzyme and to provide an atomic model for the leading strand replisome.
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33
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Binding-Induced Conformational Changes Involved in Sliding Clamp PCNA and DNA Polymerase DPO4. iScience 2020; 23:101117. [PMID: 32422591 PMCID: PMC7229285 DOI: 10.1016/j.isci.2020.101117] [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: 12/26/2019] [Revised: 03/22/2020] [Accepted: 04/26/2020] [Indexed: 11/29/2022] Open
Abstract
Cooperation between DNA polymerases and DNA sliding clamp proteins is essential for DNA replication and repair. However, it is still challenging to clarify the binding mechanism and the movements of Y-family DNA polymerase IV (DPO4) on the proliferating cell nuclear antigen (PCNA) ring. Here we develop the simulation models of DPO4–PCNA123 and DPO4–PCNA12 complexes and uncover the underlying dynamics of DPO4 during binding and the binding order of the DPO4 domains. Two important intermediate states are found on the free energy surface before reaching the final bound state. Our results suggest that both PCNA3 and DPO4 can influence the PCNA12 planar conformation, whereas the impact of PCNA3 on PCNA12 is more significant than DPO4. These findings provide the crucial information of the conformational dynamics of DPO4 and PCNA, as well as the clue of the underlying mechanism of the cooperation between DPO4 and PCNA during DNA replication. The mechanism of DPO4 binding to PCNA ring and PCNA dimer is investigated Two important intermediate states are found before reaching the final bound state Both PCNA3 and DPO4 can influence the PCNA12 planar conformation
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34
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González-Magaña A, Blanco FJ. Human PCNA Structure, Function and Interactions. Biomolecules 2020; 10:biom10040570. [PMID: 32276417 PMCID: PMC7225939 DOI: 10.3390/biom10040570] [Citation(s) in RCA: 148] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 04/01/2020] [Accepted: 04/03/2020] [Indexed: 12/13/2022] Open
Abstract
Proliferating cell nuclear antigen (PCNA) is an essential factor in DNA replication and repair. It forms a homotrimeric ring that embraces the DNA and slides along it, anchoring DNA polymerases and other DNA editing enzymes. It also interacts with regulatory proteins through a sequence motif known as PCNA Interacting Protein box (PIP-box). We here review the latest contributions to knowledge regarding the structure-function relationships in human PCNA, particularly the mechanism of sliding, and of the molecular recognition of canonical and non-canonical PIP motifs. The unique binding mode of the oncogene p15 is described in detail, and the implications of the recently discovered structure of PCNA bound to polymerase δ are discussed. The study of the post-translational modifications of PCNA and its partners may yield therapeutic opportunities in cancer treatment, in addition to illuminating the way PCNA coordinates the dynamic exchange of its many partners in DNA replication and repair.
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Affiliation(s)
- Amaia González-Magaña
- CIC bioGUNE, Bizkaia Science and Technology Park, bld 800, 48160 Derio, Bizkaia, Spain;
| | - Francisco J. Blanco
- CIC bioGUNE, Bizkaia Science and Technology Park, bld 800, 48160 Derio, Bizkaia, Spain;
- IKERBASQUE, Basque Foundation for Science, Maria Diaz de Haro 3, 6 solairua, 48013 Bilbao, Bizkaia, Spain
- Correspondence:
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35
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Madru C, Henneke G, Raia P, Hugonneau-Beaufet I, Pehau-Arnaudet G, England P, Lindahl E, Delarue M, Carroni M, Sauguet L. Structural basis for the increased processivity of D-family DNA polymerases in complex with PCNA. Nat Commun 2020; 11:1591. [PMID: 32221299 PMCID: PMC7101311 DOI: 10.1038/s41467-020-15392-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 03/05/2020] [Indexed: 11/09/2022] Open
Abstract
Replicative DNA polymerases (DNAPs) have evolved the ability to copy the genome with high processivity and fidelity. In Eukarya and Archaea, the processivity of replicative DNAPs is greatly enhanced by its binding to the proliferative cell nuclear antigen (PCNA) that encircles the DNA. We determined the cryo-EM structure of the DNA-bound PolD–PCNA complex from Pyrococcus abyssi at 3.77 Å. Using an integrative structural biology approach — combining cryo-EM, X-ray crystallography, protein–protein interaction measurements, and activity assays — we describe the molecular basis for the interaction and cooperativity between a replicative DNAP and PCNA. PolD recruits PCNA via a complex mechanism, which requires two different PIP-boxes. We infer that the second PIP-box, which is shared with the eukaryotic Polα replicative DNAP, plays a dual role in binding either PCNA or primase, and could be a master switch between an initiation and a processive phase during replication. Replicative DNA polymerases (DNAPs) have evolved the ability to copy the genome with high processivity and fidelity. Here, the authors present a cryo-EM structure of the DNA-bound PolD–PCNA complex from Pyrococcus abyssi to reveal the molecular basis for the interaction and cooperativity between a replicative DNAP and PCNA.
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Affiliation(s)
- Clément Madru
- Unit of Structural Dynamics of Macromolecules, Institut Pasteur and CNRS UMR 3528, Paris, France
| | - Ghislaine Henneke
- CNRS, Ifremer, Université de Brest, Laboratoire de Microbiologie des Environnements Extrêmes, Plouzané, France
| | - Pierre Raia
- Unit of Structural Dynamics of Macromolecules, Institut Pasteur and CNRS UMR 3528, Paris, France.,Sorbonne Université, École Doctorale Complexité du Vivant (ED515), Paris, France
| | - Inès Hugonneau-Beaufet
- Unit of Structural Dynamics of Macromolecules, Institut Pasteur and CNRS UMR 3528, Paris, France
| | | | - Patrick England
- Molecular Biophysics Platform, C2RT, Institut Pasteur, CNRS UMR 3528, Paris, France
| | - Erik Lindahl
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, Stockholm, Sweden.,Department of Applied Physics, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Marc Delarue
- Unit of Structural Dynamics of Macromolecules, Institut Pasteur and CNRS UMR 3528, Paris, France
| | - Marta Carroni
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, Stockholm, Sweden.
| | - Ludovic Sauguet
- Unit of Structural Dynamics of Macromolecules, Institut Pasteur and CNRS UMR 3528, Paris, France.
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36
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Hayes JA, Hilbert BJ, Gaubitz C, Stone NP, Kelch BA. A thermophilic phage uses a small terminase protein with a fixed helix-turn-helix geometry. J Biol Chem 2020; 295:3783-3793. [PMID: 32014998 DOI: 10.1074/jbc.ra119.012224] [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: 12/16/2019] [Revised: 01/30/2020] [Indexed: 11/06/2022] Open
Abstract
Tailed bacteriophages use a DNA-packaging motor to encapsulate their genome during viral particle assembly. The small terminase (TerS) component of this DNA-packaging machinery acts as a molecular matchmaker that recognizes both the viral genome and the main motor component, the large terminase (TerL). However, how TerS binds DNA and the TerL protein remains unclear. Here we identified gp83 of the thermophilic bacteriophage P74-26 as the TerS protein. We found that TerSP76-26 oligomerizes into a nonamer that binds DNA, stimulates TerL ATPase activity, and inhibits TerL nuclease activity. A cryo-EM structure of TerSP76-26 revealed that it forms a ring with a wide central pore and radially arrayed helix-turn-helix domains. The structure further showed that these helix-turn-helix domains, which are thought to bind DNA by wrapping the double helix around the ring, are rigidly held in an orientation distinct from that seen in other TerS proteins. This rigid arrangement of the putative DNA-binding domain imposed strong constraints on how TerSP76-26 can bind DNA. Finally, the TerSP76-26 structure lacked the conserved C-terminal β-barrel domain used by other TerS proteins for binding TerL. This suggests that a well-ordered C-terminal β-barrel domain is not required for TerSP76-26 to carry out its matchmaking function. Our work highlights a thermophilic system for studying the role of small terminase proteins in viral maturation and presents the structure of TerSP76-26, revealing key differences between this thermophilic phage and its mesophilic counterparts.
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Affiliation(s)
- Janelle A Hayes
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01655
| | - Brendan J Hilbert
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01655
| | - Christl Gaubitz
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01655
| | - Nicholas P Stone
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01655
| | - Brian A Kelch
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01655
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37
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Nowakowska K, Giebułtowicz J, Kamaszewski M, Adamski A, Szudrowicz H, Ostaszewska T, Solarska-Dzięciołowska U, Nałęcz-Jawecki G, Wroczyński P, Drobniewska A. Acute exposure of zebrafish (Danio rerio) larvae to environmental concentrations of selected antidepressants: Bioaccumulation, physiological and histological changes. Comp Biochem Physiol C Toxicol Pharmacol 2020; 229:108670. [PMID: 31733407 DOI: 10.1016/j.cbpc.2019.108670] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 10/09/2019] [Accepted: 11/12/2019] [Indexed: 12/13/2022]
Abstract
Antidepressants have been detected in surface waters worldwide at ng-μg/L concentration. These compounds can exert adverse effects on fish even at low levels. But, all previous analyses have concentrated on adult fish. The aim of the study was to assess the effect of environmental concentrations of sertraline, paroxetine, fluoxetine and mianserin, and their mixtures on such unusual endpoints as physiological and histological changes of zebrafish (Danio rerio) larvae. We also determined the bioconcentration of the pharmaceuticals. Fish Embryo Toxicity test was used to analyze the influence on developmental progression. Histological sections were stained with hematoxylin and eosin. Proliferating cells in liver were determined immunohistochemically by detection of Proliferating Cell Nuclear Antigens. The bioconcentration factor was measured by liquid chromatography coupled to mass spectrometry. Pharmaceuticals were used at low, medium and high concentrations in mixtures and at medium concentration as single compound. Exposure to the analyzed pharmaceuticals increased the rate of abnormal embryo and larvae development, accelerated the hatching time and affected the total hatching rate. Three-times lower proliferation of hepatocytes was observed in larvae exposed to paroxetine, mianserin, sertraline and the mixture of the pharmaceuticals at the highest concentrations. The highest bioaccumulation factor (BCF) was obtained for sertraline. The BCF of the analyzed compounds was higher if the organisms were exposed to the mixtures than to single pharmaceuticals. To conclude, the exposure of zebrafish larvae to selected antidepressants and their mixtures may cause disturbances in the organogenesis of fish even at environmental concentrations.
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Affiliation(s)
- Karolina Nowakowska
- Department of Bioanalysis and Drugs Analysis, Faculty of Pharmacy, Medical University of Warsaw, 1 Banacha Street, Warsaw PL-02097, Poland; Department of Environmental Health Sciences, Faculty of Pharmacy, Medical University of Warsaw, 1 Banacha Street, Warsaw PL-02097, Poland
| | - Joanna Giebułtowicz
- Department of Bioanalysis and Drugs Analysis, Faculty of Pharmacy, Medical University of Warsaw, 1 Banacha Street, Warsaw PL-02097, Poland.
| | - Maciej Kamaszewski
- Department of Ichthyology and Biotechnology in Aquaculture, Warsaw University of Life Sciences-SGGW, 8 Ciszewskiego Street, Warsaw PL-02-786, Poland
| | - Antoni Adamski
- Department of Ichthyology and Biotechnology in Aquaculture, Warsaw University of Life Sciences-SGGW, 8 Ciszewskiego Street, Warsaw PL-02-786, Poland; Institute of Biochemistry and Biophysics, Polish Academy of Science, 5a Pawinskiego Street, Warsaw PL-02106, Poland
| | - Hubert Szudrowicz
- Department of Ichthyology and Biotechnology in Aquaculture, Warsaw University of Life Sciences-SGGW, 8 Ciszewskiego Street, Warsaw PL-02-786, Poland
| | - Teresa Ostaszewska
- Department of Ichthyology and Biotechnology in Aquaculture, Warsaw University of Life Sciences-SGGW, 8 Ciszewskiego Street, Warsaw PL-02-786, Poland
| | - Urszula Solarska-Dzięciołowska
- Department of Bioanalysis and Drugs Analysis, Faculty of Pharmacy, Medical University of Warsaw, 1 Banacha Street, Warsaw PL-02097, Poland
| | - Grzegorz Nałęcz-Jawecki
- Department of Environmental Health Sciences, Faculty of Pharmacy, Medical University of Warsaw, 1 Banacha Street, Warsaw PL-02097, Poland
| | - Piotr Wroczyński
- Department of Bioanalysis and Drugs Analysis, Faculty of Pharmacy, Medical University of Warsaw, 1 Banacha Street, Warsaw PL-02097, Poland
| | - Agata Drobniewska
- Department of Environmental Health Sciences, Faculty of Pharmacy, Medical University of Warsaw, 1 Banacha Street, Warsaw PL-02097, Poland
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38
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Li H, Doruker P, Hu G, Bahar I. Modulation of Toroidal Proteins Dynamics in Favor of Functional Mechanisms upon Ligand Binding. Biophys J 2020; 118:1782-1794. [PMID: 32130874 DOI: 10.1016/j.bpj.2020.01.046] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 01/05/2020] [Accepted: 01/27/2020] [Indexed: 12/16/2022] Open
Abstract
Toroidal proteins serve as molecular machines and play crucial roles in biological processes such as DNA replication and RNA transcription. Despite progress in the structural characterization of several toroidal proteins, we still lack a mechanistic understanding of the significance of their architecture, oligomerization states, and intermolecular interactions in defining their biological function. In this work, we analyze the collective dynamics of toroidal proteins with different oligomerization states, namely, dimeric and trimeric DNA sliding clamps, nucleocapsid proteins (4-, 5-, and 6-mers) and Trp RNA-binding attenuation proteins (11- and 12-mers). We observe common global modes, among which cooperative rolling stands out as a mechanism enabling DNA processivity, and clamshell motions as those underlying the opening/closure of the sliding clamps. Alterations in global dynamics due to complexation with DNA or the clamp loader are shown to assist in enhancing motions to enable robust function. The analysis provides new insights into the differentiation and enhancement of functional motions upon intersubunit and intermolecular interactions.
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Affiliation(s)
- Hongchun Li
- Center for Systems Biology, School of Biology and Basic Medical Sciences, Soochow University, Suzhou, China; Department of Computational and Systems Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania; Research Center for Computer-Aided Drug Discovery, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Pemra Doruker
- Department of Computational and Systems Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Guang Hu
- Center for Systems Biology, School of Biology and Basic Medical Sciences, Soochow University, Suzhou, China.
| | - Ivet Bahar
- Department of Computational and Systems Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania.
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39
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Jiang X, Zhang L, An J, Wang M, Teng M, Guo Q, Li X. Caulobacter crescentus β sliding clamp employs a noncanonical regulatory model of DNA replication. FEBS J 2019; 287:2292-2311. [PMID: 31725950 DOI: 10.1111/febs.15138] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 08/23/2019] [Accepted: 11/12/2019] [Indexed: 01/19/2023]
Abstract
The eubacterial β sliding clamp (DnaN) plays a crucial role in DNA metabolism through direct interactions with DNA, polymerases, and a variety of protein factors. A canonical protein-DnaN interaction has been identified in Escherichia coli and some other species, during which protein partners are tethered into the conserved canonical hydrophobic crevice of DnaN via the consensus β-binding motif. Caulobacter crescentus is an excellent research model for use in the investigation of DNA replication and cell-cycle regulation due to its unique asymmetric cell division pattern with restricted replication initiation; however, little is known about the specific features of C. crescentus DnaN (CcDnaN). Here, we report a significant divergence in the association of CcDnaN with proteins based on docking analysis and crystal structures that show that the β-binding motifs of its protein partners bind a novel pocket instead of the canonical site. Pull-down and isothermal titration calorimetry results revealed that mutations within the novel pocket disrupt protein-CcDnaN interactions. It was also shown by replication and regulatory inactivation of DnaA assays that mediation of protein interaction by the novel pocket is closely related to the performance of CcDnaN during replication and the DnaN-mediated regulation process. Moreover, assessments of clamp competition showed that DNA does not compete with protein partners when binding to the novel pocket. Overall, our structural and biochemical analyses provide strong evidence that CcDnaN employs a noncanonical protein association pattern.
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Affiliation(s)
- Xuguang Jiang
- Hefei National Laboratory for Physical Sciences at Microscale, School of Life Sciences, National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, China.,Key Laboratory of Structural Biology, Chinese Academy of Sciences, Hefei, China
| | - Linjuan Zhang
- Hefei National Laboratory for Physical Sciences at Microscale, School of Life Sciences, National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, China.,Key Laboratory of Structural Biology, Chinese Academy of Sciences, Hefei, China
| | - Jiancheng An
- Hefei National Laboratory for Physical Sciences at Microscale, School of Life Sciences, National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, China
| | - Mingxing Wang
- Hefei National Laboratory for Physical Sciences at Microscale, School of Life Sciences, National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, China.,Key Laboratory of Structural Biology, Chinese Academy of Sciences, Hefei, China
| | - Maikun Teng
- Hefei National Laboratory for Physical Sciences at Microscale, School of Life Sciences, National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, China.,Key Laboratory of Structural Biology, Chinese Academy of Sciences, Hefei, China
| | - Qiong Guo
- Hefei National Laboratory for Physical Sciences at Microscale, School of Life Sciences, National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, China.,Key Laboratory of Structural Biology, Chinese Academy of Sciences, Hefei, China
| | - Xu Li
- Hefei National Laboratory for Physical Sciences at Microscale, School of Life Sciences, National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, China.,Key Laboratory of Structural Biology, Chinese Academy of Sciences, Hefei, China
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40
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Almawi AW, Scotland MK, Randall JR, Liu L, Martin HK, Sacre L, Shen Y, Pillon MC, Simmons LA, Sutton MD, Guarné A. Binding of the regulatory domain of MutL to the sliding β-clamp is species specific. Nucleic Acids Res 2019; 47:4831-4842. [PMID: 30916336 PMCID: PMC6511837 DOI: 10.1093/nar/gkz115] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 01/21/2019] [Accepted: 02/18/2019] [Indexed: 11/15/2022] Open
Abstract
The β-clamp is a protein hub central to DNA replication and fork management. Proteins interacting with the β-clamp harbor a conserved clamp-binding motif that is often found in extended regions. Therefore, clamp interactions have -almost exclusively- been studied using short peptides recapitulating the binding motif. This approach has revealed the molecular determinants that mediate the binding but cannot describe how proteins with clamp-binding motifs embedded in structured domains are recognized. The mismatch repair protein MutL has an internal clamp-binding motif, but its interaction with the β-clamp has different roles depending on the organism. In Bacillus subtilis, the interaction stimulates the endonuclease activity of MutL and it is critical for DNA mismatch repair. Conversely, disrupting the interaction between Escherichia coli MutL and the β-clamp only causes a mild mutator phenotype. Here, we determined the structures of the regulatory domains of E. coli and B. subtilis MutL bound to their respective β-clamps. The structures reveal different binding modes consistent with the binding to the β-clamp being a two-step process. Functional characterization indicates that, within the regulatory domain, only the clamp binding motif is required for the interaction between the two proteins. However, additional motifs beyond the regulatory domain may stabilize the interaction. We propose a model for the activation of the endonuclease activity of MutL in organisms lacking methyl-directed mismatch repair.
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Affiliation(s)
- Ahmad W Almawi
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
| | - Michelle K Scotland
- Department of Biochemistry, The Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA.,Witebsky Center for Microbial Pathogenesis and Immunology, The Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
| | - Justin R Randall
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Linda Liu
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
| | - Heather K Martin
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Lauralicia Sacre
- Department of Biochemistry, McGill University, Montreal, QC, Canada
| | - Yao Shen
- Department of Biochemistry, McGill University, Montreal, QC, Canada
| | - Monica C Pillon
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
| | - Lyle A Simmons
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Mark D Sutton
- Department of Biochemistry, The Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA.,Witebsky Center for Microbial Pathogenesis and Immunology, The Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA.,Genetics, Genomics and Bioinformatics Program, The Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
| | - Alba Guarné
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada.,Department of Biochemistry, McGill University, Montreal, QC, Canada
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41
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Daitchman D, Greenblatt HM, Levy Y. Diffusion of ring-shaped proteins along DNA: case study of sliding clamps. Nucleic Acids Res 2019; 46:5935-5949. [PMID: 29860305 PMCID: PMC6158715 DOI: 10.1093/nar/gky436] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 05/08/2018] [Indexed: 12/13/2022] Open
Abstract
Several DNA-binding proteins, such as topoisomerases, helicases and sliding clamps, have a toroidal (i.e. ring) shape that topologically traps DNA, with this quality being essential to their function. Many DNA-binding proteins that function, for example, as transcription factors or enzymes were shown to be able to diffuse linearly (i.e. slide) along DNA during the search for their target binding sites. The protein's sliding properties and ability to search DNA, which often also involves hopping and dissociation, are expected to be different when it encircles the DNA. In this study, we explored the linear diffusion of four ring-shaped proteins of very similar structure: three sliding clamps (PCNA, β-clamp, and the gp45) and the 9-1-1 protein, with a particular focus on PCNA. Coarse-grained molecular dynamics simulations were performed to decipher the sliding mechanism adopted by these ring-shaped proteins and to determine how the molecular properties of the inner and outer ring govern its search speed. We designed in silico variants to dissect the contributions of ring geometry and electrostatics to the sliding speed of ring-shaped proteins along DNA. We found that the toroidal proteins diffuse when they are tilted relative to the DNA axis and able to rotate during translocation, but that coupling between rotation and translocation is quite weak. Their diffusion speed is affected by the shape of the inner ring and, to a lesser extent, by its electrostatic properties. However, breaking the symmetry of the electrostatic potential can result in deviation of the DNA from the center of the ring and cause slower linear diffusion. The findings are discussed in light of earlier computational and experimental studies on the sliding of clamps.
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Affiliation(s)
- Dina Daitchman
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Harry M Greenblatt
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Yaakov Levy
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
- To whom correspondence should be addressed. Tel: +972 8 9344587;
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42
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Dynamics of the E. coli β-Clamp Dimer Interface and Its Influence on DNA Loading. Biophys J 2019; 117:587-601. [PMID: 31349986 DOI: 10.1016/j.bpj.2019.06.035] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 06/21/2019] [Accepted: 06/27/2019] [Indexed: 01/17/2023] Open
Abstract
The ring-shaped sliding clamp proteins have crucial roles in the regulation of DNA replication, recombination, and repair in all organisms. We previously showed that the Escherichia coli β-clamp is dynamic in solution, transiently visiting conformational states in which Domain 1 at the dimer interface is more flexible and prone to unfolding. This work aims to understand how the stability of the dimer interface influences clamp-opening dynamics and clamp loading by designing and characterizing stabilizing and destabilizing mutations in the clamp. The variants with stabilizing mutations conferred similar or increased thermostability and had similar quaternary structure as compared to the wild type. These variants stimulated the ATPase function of the clamp loader, complemented cell growth of a temperature-sensitive strain, and were successfully loaded onto a DNA substrate. The L82D and L82E I272A variants with purported destabilizing mutations had decreased thermostability, did not complement the growth of a temperature-sensitive strain, and had weakened dimerization as determined by native trapped ion mobility spectrometry-mass spectrometry. The β L82E variant had a reduced melting temperature but dimerized and complemented growth of a temperature-sensitive strain. All three clamps with destabilizing mutations had perturbed loading on DNA. Molecular dynamics simulations indicate altered hydrogen-bonding patterns at the dimer interface, and cross-correlation analysis showed the largest perturbations in the destabilized variants, consistent with the observed change in the conformations and functions of these clamps.
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43
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De March M, Barrera-Vilarmau S, Crespan E, Mentegari E, Merino N, Gonzalez-Magaña A, Romano-Moreno M, Maga G, Crehuet R, Onesti S, Blanco FJ, De Biasio A. p15PAF binding to PCNA modulates the DNA sliding surface. Nucleic Acids Res 2019; 46:9816-9828. [PMID: 30102405 PMCID: PMC6182140 DOI: 10.1093/nar/gky723] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 07/31/2018] [Indexed: 12/15/2022] Open
Abstract
p15PAF is an oncogenic intrinsically disordered protein that regulates DNA replication and lesion bypass by interacting with the human sliding clamp PCNA. In the absence of DNA, p15PAF traverses the PCNA ring via an extended PIP-box that contacts the sliding surface. Here, we probed the atomic-scale structure of p15PAF–PCNA–DNA ternary complexes. Crystallography and MD simulations show that, when p15PAF occupies two subunits of the PCNA homotrimer, DNA within the ring channel binds the unoccupied subunit. The structure of PCNA-bound p15PAF in the absence and presence of DNA is invariant, and solution NMR confirms that DNA does not displace p15PAF from the ring wall. Thus, p15PAF reduces the available sliding surfaces of PCNA, and may function as a belt that fastens the DNA to the clamp during synthesis by the replicative polymerase (pol δ). This constraint, however, may need to be released for efficient DNA lesion bypass by the translesion synthesis polymerase (pol η). Accordingly, our biochemical data show that p15PAF impairs primer synthesis by pol η–PCNA holoenzyme against both damaged and normal DNA templates. In light of our findings, we discuss the possible mechanistic roles of p15PAF in DNA replication and suppression of DNA lesion bypass.
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Affiliation(s)
- Matteo De March
- Structural Biology Laboratory, Elettra-Sincrotrone Trieste S.C.p.A., Trieste 34149, Italy
| | - Susana Barrera-Vilarmau
- Institute of Advanced Chemistry of Catalonia (IQAC), CSIC, Jordi Girona 18-26, 08034, Barcelona, Spain
| | - Emmanuele Crespan
- Institute of Molecular Genetics, IGM-CNR, via Abbiategrasso 207, 27100 Pavia, Italy
| | - Elisa Mentegari
- Institute of Molecular Genetics, IGM-CNR, via Abbiategrasso 207, 27100 Pavia, Italy
| | - Nekane Merino
- CIC bioGUNE, Parque Tecnológico de Bizkaia Edificio 800, 48160 Derio, Spain
| | | | | | - Giovanni Maga
- Institute of Molecular Genetics, IGM-CNR, via Abbiategrasso 207, 27100 Pavia, Italy
| | - Ramon Crehuet
- Institute of Advanced Chemistry of Catalonia (IQAC), CSIC, Jordi Girona 18-26, 08034, Barcelona, Spain
| | - Silvia Onesti
- Structural Biology Laboratory, Elettra-Sincrotrone Trieste S.C.p.A., Trieste 34149, Italy
| | - Francisco J Blanco
- CIC bioGUNE, Parque Tecnológico de Bizkaia Edificio 800, 48160 Derio, Spain.,IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - Alfredo De Biasio
- Structural Biology Laboratory, Elettra-Sincrotrone Trieste S.C.p.A., Trieste 34149, Italy.,Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell Biology, University of Leicester, Lancaster Rd, Leicester LE1 7HB, UK
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44
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Abstract
DNA sliding clamps are rings that tether certain enzymes to DNA. How clamp proteins slide on DNA has remained a mystery. A new crystal structure, together with molecular dynamics and NMR studies, has revealed how the human PCNA clamp slides on DNA.
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Affiliation(s)
- Nina Y Yao
- The Rockefeller University, 1230 York Avenue, New York City, NY 10065, USA
| | - Mike O'Donnell
- The Rockefeller University, 1230 York Avenue, New York City, NY 10065, USA; Howard Hughes Medical Institute, 1230 York Avenue, New York City, NY 10065, USA.
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45
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Qian J, Chen Y, Xu Y, Zhang X, Kang Z, Jiao J, Zhao J. Interactional similarities and differences in the protein complex of PCNA and DNA replication factor C between rice and Arabidopsis. BMC PLANT BIOLOGY 2019; 19:257. [PMID: 31200645 PMCID: PMC6570896 DOI: 10.1186/s12870-019-1874-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Accepted: 06/06/2019] [Indexed: 05/30/2023]
Abstract
BACKGROUND Proliferating cell nuclear antigen (PCNA), a conserved trimeric ring complex, is loaded onto replication fork through a hetero-pentameric AAA+ ATPase complex termed replication factor C (RFC) to maintain genome stability. Although architectures of PCNA-RFC complex in yeast have been revealed, the functions of PCNA and protein-protein interactions of PCNA-RFC complex in higher plants are not very clear. Here, essential regions mediating interactions between PCNA and RFC subunits in Arabidopsis and rice were investigated via yeast-two-hybrid method and bimolecular fluorescence complementation techniques. RESULTS We observed that OsPCNA could interact with all OsRFC subunits, while protein-protein interactions only exist between Arabidopsis RFC2/3/4/5 and AtPCNA1/2. The truncated analyses indicated that the C-terminal of Arabidopsis RFC2/3/4/5 and rice RFC1/2 is essential for binding PCNA while the region of rice RFC3/4/5 mediating interaction with PCNA distributed both at the N- and C-terminal. On the other hand, we found that the C- and N-terminal of Arabidopsis and rice PCNA contribute equally to PCNA-PCNA interaction, and the interdomain connecting loop (IDCL) domain and C-terminal of PCNAs are indispensable for interacting RFC subunits. CONCLUSIONS These results indicated that Arabidopsis and rice PCNAs are highly conserved in sequence, structure and pattern of interacting with other PCNA monomer. Nevertheless, there are also significant differences between the Arabidopsis and rice RFC subunits in binding PCNA. Taken together, our results could be helpful for revealing the biological functions of plant RFC-PCNA complex.
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Affiliation(s)
- Jie Qian
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Yueyue Chen
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Yaxing Xu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Xiufeng Zhang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Zhuang Kang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Jinxia Jiao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Jie Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China.
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46
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Oakley AJ. A structural view of bacterial DNA replication. Protein Sci 2019; 28:990-1004. [PMID: 30945375 DOI: 10.1002/pro.3615] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 04/03/2019] [Indexed: 11/11/2022]
Abstract
DNA replication mechanisms are conserved across all organisms. The proteins required to initiate, coordinate, and complete the replication process are best characterized in model organisms such as Escherichia coli. These include nucleotide triphosphate-driven nanomachines such as the DNA-unwinding helicase DnaB and the clamp loader complex that loads DNA-clamps onto primer-template junctions. DNA-clamps are required for the processivity of the DNA polymerase III core, a heterotrimer of α, ε, and θ, required for leading- and lagging-strand synthesis. DnaB binds the DnaG primase that synthesizes RNA primers on both strands. Representative structures are available for most classes of DNA replication proteins, although there are gaps in our understanding of their interactions and the structural transitions that occur in nanomachines such as the helicase, clamp loader, and replicase core as they function. Reviewed here is the structural biology of these bacterial DNA replication proteins and prospects for future research.
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Affiliation(s)
- Aaron J Oakley
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, and Illawarra Health and Medical Research Institute, Wollongong, New South Wales, Australia
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47
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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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48
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Patoli AA, Patoli BB. The N-Terminal 6×His Tag on β-Clamp Processivity Factor Occludes Gly66 and Affects the Growth of Escherichia coli B834 (DE3) Cells. Mol Biol 2019. [DOI: 10.1134/s0026893319010126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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49
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McGrath AE, Martyn AP, Whittell LR, Dawes FE, Beck JL, Dixon NE, Kelso MJ, Oakley AJ. Crystal structures and biochemical characterization of DNA sliding clamps from three Gram-negative bacterial pathogens. J Struct Biol 2018; 204:396-405. [DOI: 10.1016/j.jsb.2018.10.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 10/20/2018] [Accepted: 10/22/2018] [Indexed: 12/19/2022]
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50
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Xu ZQ, Dixon NE. Bacterial replisomes. Curr Opin Struct Biol 2018; 53:159-168. [PMID: 30292863 DOI: 10.1016/j.sbi.2018.09.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 09/07/2018] [Accepted: 09/17/2018] [Indexed: 01/18/2023]
Abstract
Bacterial replisomes are dynamic multiprotein DNA replication machines that are inherently difficult for structural studies. However, breakthroughs continue to come. The structures of Escherichia coli DNA polymerase III (core)-clamp-DNA subcomplexes solved by single-particle cryo-electron microscopy in both polymerization and proofreading modes and the discovery of the stochastic nature of the bacterial replisomes represent notable progress. The structures reveal an intricate interaction network in the polymerase-clamp subassembly, providing insights on how replisomes may work. Meantime, ensemble and single-molecule functional assays and fluorescence microscopy show that the bacterial replisomes can work in a decoupled and uncoordinated way, with polymerases quickly exchanging and both leading-strand and lagging-strand polymerases and the helicase working independently, contradictory to the elegant textbook view of a highly coordinated machine.
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Affiliation(s)
- Zhi-Qiang Xu
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, and Illawarra Health and Medical Research Institute, Wollongong, New South Wales 2522, Australia
| | - Nicholas E Dixon
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, and Illawarra Health and Medical Research Institute, Wollongong, New South Wales 2522, Australia.
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