1
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Inoue S, Ikeda Y, Fujiyama S, Ueda T, Abe Y. Oligomeric state of the N-terminal domain of DnaT for replication restart in Escherichia coli. BIOCHIMICA ET BIOPHYSICA ACTA. PROTEINS AND PROTEOMICS 2023:140929. [PMID: 37328019 DOI: 10.1016/j.bbapap.2023.140929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 06/09/2023] [Accepted: 06/12/2023] [Indexed: 06/18/2023]
Abstract
DNA replication stops when chemical or physical damage occurs to the DNA. Repairing genomic DNA and reloading the replication helicase are crucial steps for restarting DNA replication. The Escherichia coli primosome is a complex of proteins and DNA responsible for reloading the replication helicase DnaB. DnaT, a protein found in the primosome complex, contains two functional domains. The C-terminal domain (89-179) forms an oligomeric complex with single-stranded DNA. Although the N-terminal domain (1-88) forms an oligomer, the specific residues responsible for this oligomeric structure have not yet been identified. In this study, we proposed that the N-terminal domain of DnaT has a dimeric antitoxin structure based on its primary sequence. Based on the proposed model, we confirmed the site of oligomerization in the N-terminal domain of DnaT through site-directed mutagenesis. The molecular masses and thermodynamic stabilities of the site-directed mutants located at the dimer interface, namely Phe42, Tyr43, Leu50, Leu53, and Leu54, were found to be lower than those of the wild-type. Moreover, we observed a decrease in the molecular masses of the V10S and F35S mutants compared to the wild-type DnaT. NMR analysis of the V10S mutant revealed that the secondary structure of the N-terminal domain of DnaT was consistent with the proposed model. Additionally, we have demonstrated that the stability of the oligomer formed by the N-terminal domain of DnaT is crucial for its function. Based on these findings, we propose that the DnaT oligomer plays a role in replication restart in Escherichia coli.
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Affiliation(s)
- Shogo Inoue
- Department of Protein Structure, Function and Design, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Yohei Ikeda
- Department of Protein Structure, Function and Design, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Saki Fujiyama
- Department of Protein Structure, Function and Design, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Tadashi Ueda
- Department of Protein Structure, Function and Design, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Yoshito Abe
- Department of Protein Structure, Function and Design, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan; Department of Pharmaceutical Sciences, School of Pharmacy at Fukuoka, International University of Health and Welfare, Okawa 831-8501, Japan.
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2
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Duckworth AT, Ducos PL, McMillan SD, Satyshur KA, Blumenthal KH, Deorio HR, Larson JA, Sandler SJ, Grant T, Keck JL. Replication fork binding triggers structural changes in the PriA helicase that govern DNA replication restart in E. coli. Nat Commun 2023; 14:2725. [PMID: 37169801 PMCID: PMC10175261 DOI: 10.1038/s41467-023-38144-x] [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: 01/06/2023] [Accepted: 04/18/2023] [Indexed: 05/13/2023] Open
Abstract
Bacterial replisomes often dissociate from replication forks before chromosomal replication is complete. To avoid the lethal consequences of such situations, bacteria have evolved replication restart pathways that reload replisomes onto prematurely terminated replication forks. To understand how the primary replication restart pathway in E. coli (PriA-PriB) selectively acts on replication forks, we determined the cryogenic-electron microscopy structure of a PriA/PriB/replication fork complex. Replication fork specificity arises from extensive PriA interactions with each arm of the branched DNA. These interactions reshape the PriA protein to create a pore encircling single-stranded lagging-strand DNA while also exposing a surface of PriA onto which PriB docks. Together with supporting biochemical and genetic studies, the structure reveals a switch-like mechanism for replication restart initiation in which restructuring of PriA directly couples replication fork recognition to PriA/PriB complex formation to ensure robust and high-fidelity replication re-initiation.
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Affiliation(s)
- Alexander T Duckworth
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Peter L Ducos
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
- John and Jeanne Rowe Center for Research in Virology, Morgridge Institute for Research, Madison, WI, 53715, USA
| | - Sarah D McMillan
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Kenneth A Satyshur
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Katelien H Blumenthal
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Haley R Deorio
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Joseph A Larson
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Steven J Sandler
- Department of Microbiology, University of Massachusetts at Amherst, Amherst, MA, 01003, USA.
| | - Timothy Grant
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA.
- John and Jeanne Rowe Center for Research in Virology, Morgridge Institute for Research, Madison, WI, 53715, USA.
| | - James L Keck
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA.
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3
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McKenzie AM, Henry C, Myers KS, Place MM, Keck JL. Identification of genetic interactions with priB links the PriA/PriB DNA replication restart pathway to double-strand DNA break repair in Escherichia coli. G3 (BETHESDA, MD.) 2022; 12:jkac295. [PMID: 36326440 PMCID: PMC9713433 DOI: 10.1093/g3journal/jkac295] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 10/20/2022] [Indexed: 11/30/2023]
Abstract
Collisions between DNA replication complexes (replisomes) and impediments such as damaged DNA or proteins tightly bound to the chromosome lead to premature dissociation of replisomes at least once per cell cycle in Escherichia coli. Left unrepaired, these events produce incompletely replicated chromosomes that cannot be properly partitioned into daughter cells. DNA replication restart, the process that reloads replisomes at prematurely terminated sites, is therefore essential in E. coli and other bacteria. Three replication restart pathways have been identified in E. coli: PriA/PriB, PriA/PriC, and PriC/Rep. A limited number of genetic interactions between replication restart and other genome maintenance pathways have been defined, but a systematic study placing replication restart reactions in a broader cellular context has not been performed. We have utilized transposon-insertion sequencing to identify new genetic interactions between DNA replication restart pathways and other cellular systems. Known genetic interactors with the priB replication restart gene (uniquely involved in the PriA/PriB pathway) were confirmed and several novel priB interactions were discovered. Targeted genetic and imaging-based experiments with priB and its genetic partners revealed significant double-strand DNA break accumulation in strains with mutations in dam, rep, rdgC, lexA, or polA. Modulating the activity of the RecA recombinase partially suppressed the detrimental effects of rdgC or lexA mutations in ΔpriB cells. Taken together, our results highlight roles for several genes in double-strand DNA break homeostasis and define a genetic network that facilitates DNA repair/processing upstream of PriA/PriB-mediated DNA replication restart in E. coli.
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Affiliation(s)
- Aidan M McKenzie
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA
| | - Camille Henry
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Kevin S Myers
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI 53726, USA
| | - Michael M Place
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI 53726, USA
| | - James L Keck
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA
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4
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Masai H. TT-pocket/HIRAN: binding to 3'-terminus of DNA for recognition and processing of stalled replication forks. J Biochem 2022; 172:57-60. [PMID: 35662338 DOI: 10.1093/jb/mvac042] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Accepted: 03/06/2022] [Indexed: 11/13/2022] Open
Abstract
Stalled replication forks need to be swiftly detected, protected from collapse, and the cause for fork stall be removed to restore the active replication fork. In bacteria, stalled forks are recognized and stabilized by PriA, a DEXH-type helicase, which also facilitates reassembly of an active replication fork. A TT-pocket (three-prime terminus binding pocket) present in the N-terminal segment of PriA plays a crucial role in stabilization of the stalled forks by specifically binding to the 3'-terminus of the nascent leading strand. Eukaryotic proteins, Rad5/HLTF, contain a TT-pocket related domain, HIRAN, that specifically binds to 3'-terminus of DNA, and play a role in stalled fork processing. While the TT-pocket of PriA facilitates the formation of an apparently stable and immobile complex on a fork with a 3'-terminus at the fork junction, HIRAN of Rad5/HLTF facilitates fork regression by itself. A recent report shows that HIRAN can displace 3 nucleotides at the end of the duplex DNA, providing mechanistic insight into how stalled forks are reversed in eukaryotes. In this article, I will compare the roles of 3'-terminus binding domains in stalled fork processing in prokaryotes and in eukaryotes.
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Affiliation(s)
- Hisao Masai
- Department of Basic Medical Sciences, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan
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5
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Bianco PR. OB-fold Families of Genome Guardians: A Universal Theme Constructed From the Small β-barrel Building Block. Front Mol Biosci 2022; 9:784451. [PMID: 35223988 PMCID: PMC8881015 DOI: 10.3389/fmolb.2022.784451] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 01/19/2022] [Indexed: 11/13/2022] Open
Abstract
The maintenance of genome stability requires the coordinated actions of multiple proteins and protein complexes, that are collectively known as genome guardians. Within this broadly defined family is a subset of proteins that contain oligonucleotide/oligosaccharide-binding folds (OB-fold). While OB-folds are widely associated with binding to single-stranded DNA this view is no longer an accurate depiction of how these domains are utilized. Instead, the core of the OB-fold is modified and adapted to facilitate binding to a variety of DNA substrates (both single- and double-stranded), phospholipids, and proteins, as well as enabling catalytic function to a multi-subunit complex. The flexibility accompanied by distinctive oligomerization states and quaternary structures enables OB-fold genome guardians to maintain the integrity of the genome via a myriad of complex and dynamic, protein-protein; protein-DNA, and protein-lipid interactions in both prokaryotes and eukaryotes.
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Affiliation(s)
- Piero R. Bianco
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE, United States
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6
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Bianco PR. Insight into the biochemical mechanism of DNA helicases provided by bulk-phase and single-molecule assays. Methods 2021; 204:348-360. [PMID: 34896247 PMCID: PMC9534331 DOI: 10.1016/j.ymeth.2021.12.002] [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: 10/18/2021] [Revised: 12/01/2021] [Accepted: 12/03/2021] [Indexed: 10/19/2022] Open
Abstract
There are multiple assays available that can provide insight into the biochemical mechanism of DNA helicases. For the first 22 years since their discovery, bulk-phase assays were used. These include gel-based, spectrophotometric, and spectrofluorometric assays that revealed many facets of these enzymes. From 2001, single-molecule studies have contributed additional insight into these DNA nanomachines to reveal details on energy coupling, step size, processivity as well as unique aspects of individual enzyme behavior that were masked in the averaging inherent in ensemble studies. In this review, important aspects of the study of helicases are discussed including beginning with active, nuclease-free enzyme, followed by several bulk-phase approaches that have been developed and still find widespread use today. Finally, two single-molecule approaches are discussed, and the resulting findings are related to the results obtained in bulk-phase studies.
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Affiliation(s)
- Piero R Bianco
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE 68198-6025, USA.
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7
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Duckworth AT, Windgassen TA, Keck JL. Examination of the roles of a conserved motif in the PriA helicase in structure-specific DNA unwinding and processivity. PLoS One 2021; 16:e0255409. [PMID: 34329356 PMCID: PMC8323898 DOI: 10.1371/journal.pone.0255409] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 07/15/2021] [Indexed: 11/24/2022] Open
Abstract
DNA replication complexes (replisomes) frequently encounter barriers that can eject them prematurely from the genome. To avoid the lethality of incomplete DNA replication that arises from these events, bacteria have evolved “DNA replication restart” mechanisms to reload replisomes onto abandoned replication forks. The Escherichia coli PriA DNA helicase orchestrates this process by recognizing and remodeling replication forks and recruiting additional proteins that help to drive replisome reloading. We have identified a conserved sequence motif within a linker region of PriA that docks into a groove on the exterior of the PriA helicase domain. Alterations to the motif reduce the apparent processivity and attenuate structure-specific helicase activity in PriA, implicating the motif as a potential autoregulatory element in replication fork processing. The study also suggests that multiple PriA molecules may function in tandem to enhance DNA unwinding processivity, highlighting an unexpected similarity between PriA and other DNA helicases.
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Affiliation(s)
- Alexander T. Duckworth
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Tricia A. Windgassen
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, United States of America
- Codexis Inc, Redwood City, CA, United States of America
| | - James L. Keck
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, United States of America
- * E-mail:
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8
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Tan HY, Bianco PR. SSB Facilitates Fork-Substrate Discrimination by the PriA DNA Helicase. ACS OMEGA 2021; 6:16324-16335. [PMID: 34235303 PMCID: PMC8246471 DOI: 10.1021/acsomega.1c00722] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 05/19/2021] [Indexed: 06/13/2023]
Abstract
Primosomal protein A (PriA) is a member of helicase SuperFamily 2. Its role in vivo is to reload the primosome onto resurrected replication forks resulting in the restart of the previously stalled DNA replication process. Single-stranded DNA-binding protein (SSB) plays a key role in mediating activities at replication forks and interacts both physically and functionally with PriA. To gain a mechanistic insight into the PriA-SSB interaction, a coupled spectrophotometric assay was utilized to characterize the ATPase activity of PriA in vitro in the presence of fork substrates. The results demonstrate that SSB enhances the ability of PriA to discriminate between fork substrates as much as 140-fold. This is due to a significant increase in the catalytic efficiency of the helicase induced by SSB. This interaction is species-specific as bacteriophage gene 32 protein cannot substitute for the Escherichia coli protein. SSB, while enhancing the activity of PriA on its preferred fork decreases both the affinity of the helicase for other forks and the catalytic efficiency. Central to the stimulation afforded by SSB is the unique ability of PriA to bind with high affinity to the 3'-OH placed at the end of the nascent leading strand at the fork. When both the 3'-OH and SSB are present, the maximum effect on the ATPase activity of the helicase is observed. This ensures that PriA will load onto the correct fork, in the right orientation, thereby ensuring that replication restart is directed to only the template lagging strand.
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Affiliation(s)
| | - Piero R. Bianco
- Department of Pharmaceutical Sciences,
College of Pharmacy, University of Nebraska
Medical Center, Omaha, Nebraska 68198-6025, United States
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9
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Lee TY, Li YC, Lin MG, Hsiao CD, Li HW. Single-molecule binding characterization of primosomal protein PriA involved in replication restart. Phys Chem Chem Phys 2021; 23:13745-13751. [PMID: 34159970 DOI: 10.1039/d1cp00638j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
DNA damage leads to stalled or collapsed replication forks. Replication restart primosomes re-initiate DNA synthesis at these stalled or collapsed DNA replication forks, which is important for bacterial survival. Primosomal protein PriA specifically recognizes the DNA fork structure and recruits other primosomal proteins to load the replicative helicase, in order to re-establish the replication fork. PriA binding on DNA is the first step to restart replication forks for proper DNA repair. Using a single-molecule fluorescence colocalization experiment, we measured the thermodynamic and real-time kinetic properties of fluorescence-labeled Gram-positive bacteria Geobacillus stearothermophilus PriA binding on DNA forks. We showed that PriA preferentially binds to a DNA fork structure with a fully duplexed leading strand at sub-nanomolar affinity (Kd = 268 ± 99 pM). PriA binds dynamically, and its association and dissociation rate constants can be determined using the appearance and disappearance of the fluorescence signal. In addition, we showed that PriA binds to DNA forks as a monomer using photobleaching step counting. This information offers a molecular basis essential for understanding the mechanism of replication restart.
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Affiliation(s)
- Tzu-Yu Lee
- Department of Chemistry, National Taiwan University, Taiwan.
| | - Yi-Ching Li
- Institute of Molecular Biology, Academia Sinica, Taiwan.
| | - Min-Guan Lin
- Institute of Molecular Biology, Academia Sinica, Taiwan.
| | | | - Hung-Wen Li
- Department of Chemistry, National Taiwan University, Taiwan.
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10
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Characterization of Streptococcus pneumoniae PriA helicase and its ATPase and unwinding activities in DNA replication restart. Biochem J 2021; 477:3911-3922. [PMID: 32985663 DOI: 10.1042/bcj20200269] [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] [Received: 04/14/2020] [Revised: 09/24/2020] [Accepted: 09/25/2020] [Indexed: 11/17/2022]
Abstract
DNA replication forks often encounter template DNA lesions that can stall their progression. The PriA-dependent pathway is the major replication restart mechanism in Gram-positive bacteria, and it requires several primosome proteins. Among them, PriA protein - a 3' to 5' superfamily-2 DNA helicase - is the key factor in recognizing DNA lesions and it also recruits other proteins. Here, we investigated the ATPase and helicase activities of Streptococcus pneumoniae PriA (SpPriA) through biochemical and kinetic analyses. By comparing various DNA substrates, we observed that SpPriA is unable to unwind duplex DNA with high GC content. We constructed a deletion mutant protein (SpPriAdeloop) from which the loop area of the DNA-binding domain of PriA had been removed. Functional assays on SpPriAdeloop revealed that the loop area is important in endowing DNA-binding properties on the helicase. We also show that the presence of DnaD loader protein is important for enhancing SpPriA ATPase and DNA unwinding activities.
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11
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Hishiki A, Sato M, Hashimoto H. Structure of HIRAN domain of human HLTF bound to duplex DNA provides structural basis for DNA unwinding to initiate replication fork regression. J Biochem 2021; 167:597-602. [PMID: 31960921 DOI: 10.1093/jb/mvaa008] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 01/13/2020] [Indexed: 01/06/2023] Open
Abstract
Replication fork regression is a mechanism to rescue a stalled fork by various replication stresses, such as DNA lesions. Helicase-like transcription factor, a SNF2 translocase, plays a central role in the fork regression and its N-terminal domain, HIRAN (HIP116 and Rad5 N-terminal), binds the 3'-hydroxy group of single-stranded DNA. Furthermore, HIRAN is supposed to bind double-stranded DNA (dsDNA) and involved in strand separation in the fork regression, whereas structural basis for mechanisms underlying dsDNA binding and strand separation by HIRAN are still unclear. Here, we report the crystal structure of HIRAN bound to duplex DNA. The structure reveals that HIRAN binds the 3'-hydroxy group of DNA and unexpectedly unwinds three nucleobases of the duplex. Phe-142 is involved in the dsDNA binding and the strand separation. In addition, the structure unravels the mechanism underlying sequence-independent recognition for purine bases by HIRAN, where the N-glycosidic bond adopts syn conformation. Our findings indicate direct involvement of HIRAN in the fork regression by separating of the daughter strand from the parental template.
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Affiliation(s)
- Asami Hishiki
- School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8002, Japan
| | - Mamoru Sato
- Graduate School of Medical Life Sciences, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Hiroshi Hashimoto
- School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8002, Japan
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12
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Abe Y, Ikeda Y, Fujiyama S, Kini RM, Ueda T. A structural model of the PriB-DnaT complex in Escherichia coli replication restart. FEBS Lett 2020; 595:341-350. [PMID: 33275781 DOI: 10.1002/1873-3468.14020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 11/05/2020] [Accepted: 11/30/2020] [Indexed: 12/18/2022]
Abstract
In Escherichia coli, DNA replication is restarted following DNA repair by the PriA-dependent pathway, in which the binding and dissociation of proteins such as PriA, PriB, and DnaT on ssDNA lead to the formation of a protein-DNA complex for recruiting the DnaB-DnaC replication protein complex. However, the structure of the PriB-DnaT complex, which is an essential step in the PriA-dependent pathway, remains elusive. In this study, the importance of His26 in PriB for replication restart was reconfirmed using plasmid complementation. Furthermore, we used NMR to examine the DnaT interaction sites on PriB. We also evaluated the PriB-DnaT peptide complex model, which was prepared by in silico docking, using molecular dynamic simulation. From these data, we propose a structural model that provides insight into the PriB-DnaT interaction.
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Affiliation(s)
- Yoshito Abe
- Department of Protein Structure, Function and Design, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.,Department of Pharmaceutical Sciences, School of Pharmacy at Fukuoka, International University of Health and Welfare, Okawa, Japan
| | - Yohei Ikeda
- Department of Protein Structure, Function and Design, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Saki Fujiyama
- Department of Protein Structure, Function and Design, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - R Manjunatha Kini
- Protein Science Laboratory, Department of Biological Sciences, National University of Singapore, Singapore.,Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Tadashi Ueda
- Department of Protein Structure, Function and Design, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
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13
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Hishiki A, Sato M, Hashimoto H. Structure of the HLTF HIRAN domain and its functional implications in regression of a stalled replication fork. Acta Crystallogr D Struct Biol 2020; 76:729-735. [PMID: 32744255 DOI: 10.1107/s2059798320008074] [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: 03/10/2020] [Accepted: 06/16/2020] [Indexed: 11/10/2022] Open
Abstract
HLTF (helicase-like transcription factor) is a yeast RAD5 homolog that is found in mammals. HLTF has E3 ubiquitin ligase and DNA helicase activities, and is a pivotal protein in template-switched DNA synthesis that allows DNA replication to continue even in the presence of DNA damage by utilizing a newly synthesized undamaged strand as a template. In addition, HLTF has a DNA-binding domain termed HIRAN (HIP116 and RAD5 N-terminal). HIRAN has been hypothesized to play a role in DNA binding; however, the structural basis of its role in DNA binding has remained unclear. In the past five years, several crystal structures of HIRAN have been reported. These structures revealed new insights into the molecular mechanism underlying DNA binding by HIRAN. Here, the structural information on HIRAN is summarized and the function of HIRAN in recognizing the 3'-terminus of the daughter strand at a stalled replication fork and the implications for its involvement in fork regression are discussed.
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Affiliation(s)
- Asami Hishiki
- School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8002, Japan
| | - Mamoru Sato
- Graduate School of Medical Life Sciences, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Hiroshi Hashimoto
- School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8002, Japan
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14
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Ding W, Tan HY, Zhang JX, Wilczek LA, Hsieh KR, Mulkin JA, Bianco PR. The mechanism of Single strand binding protein-RecG binding: Implications for SSB interactome function. Protein Sci 2020; 29:1211-1227. [PMID: 32196797 PMCID: PMC7184773 DOI: 10.1002/pro.3855] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 03/11/2020] [Accepted: 03/13/2020] [Indexed: 01/10/2023]
Abstract
The Escherichia coli single-strand DNA binding protein (SSB) is essential to viability where it functions to regulate SSB interactome function. Here it binds to single-stranded DNA and to target proteins that comprise the interactome. The region of SSB that links these two essential protein functions is the intrinsically disordered linker. Key to linker function is the presence of three, conserved PXXP motifs that mediate binding to oligosaccharide-oligonucleotide binding folds (OB-fold) present in SSB and its interactome partners. Not surprisingly, partner OB-fold deletions eliminate SSB binding. Furthermore, single point mutations in either the PXXP motifs or, in the RecG OB-fold, obliterate SSB binding. The data also demonstrate that, and in contrast to the view currently held in the field, the C-terminal acidic tip of SSB is not required for interactome partner binding. Instead, we propose the tip has two roles. First, and consistent with the proposal of Dixon, to regulate the structure of the C-terminal domain in a biologically active conformation that prevents linkers from binding to SSB OB-folds until this interaction is required. Second, as a secondary binding domain. Finally, as OB-folds are present in SSB and many of its partners, we present the SSB interactome as the first family of OB-fold genome guardians identified in prokaryotes.
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Affiliation(s)
- Wenfei Ding
- Center for Single Molecule BiophysicsUniversity at BuffaloBuffaloNew YorkUnited States
- Department of BiochemistryUniversity at BuffaloBuffaloNew YorkUnited States
| | - Hui Yin Tan
- Center for Single Molecule BiophysicsUniversity at BuffaloBuffaloNew YorkUnited States
- Present address:
Department of Chemistry and BiochemistryUniversity of Notre DameSouth BendIndianaUnited States
| | - Jia Xiang Zhang
- Department of BiochemistryUniversity at BuffaloBuffaloNew YorkUnited States
| | - Luke A. Wilczek
- Center for Single Molecule BiophysicsUniversity at BuffaloBuffaloNew YorkUnited States
- Department of BiochemistryUniversity at BuffaloBuffaloNew YorkUnited States
- Present address:
Department of ChemistryBrown UniversityProvidenceRhode IslandUnited States
| | - Karin R. Hsieh
- Center for Single Molecule BiophysicsUniversity at BuffaloBuffaloNew YorkUnited States
| | - Jeffrey A. Mulkin
- Center for Single Molecule BiophysicsUniversity at BuffaloBuffaloNew YorkUnited States
| | - Piero R. Bianco
- Center for Single Molecule BiophysicsUniversity at BuffaloBuffaloNew YorkUnited States
- Department of BiochemistryUniversity at BuffaloBuffaloNew YorkUnited States
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15
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Bianco PR. DNA Helicase-SSB Interactions Critical to the Regression and Restart of Stalled DNA Replication forks in Escherichia coli. Genes (Basel) 2020; 11:E471. [PMID: 32357475 PMCID: PMC7290993 DOI: 10.3390/genes11050471] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 04/21/2020] [Accepted: 04/23/2020] [Indexed: 01/25/2023] Open
Abstract
In Escherichia coli, DNA replication forks stall on average once per cell cycle. When this occurs, replisome components disengage from the DNA, exposing an intact, or nearly intact fork. Consequently, the fork structure must be regressed away from the initial impediment so that repair can occur. Regression is catalyzed by the powerful, monomeric DNA helicase, RecG. During this reaction, the enzyme couples unwinding of fork arms to rewinding of duplex DNA resulting in the formation of a Holliday junction. RecG works against large opposing forces enabling it to clear the fork of bound proteins. Following subsequent processing of the extruded junction, the PriA helicase mediates reloading of the replicative helicase DnaB leading to the resumption of DNA replication. The single-strand binding protein (SSB) plays a key role in mediating PriA and RecG functions at forks. It binds to each enzyme via linker/OB-fold interactions and controls helicase-fork loading sites in a substrate-dependent manner that involves helicase remodeling. Finally, it is displaced by RecG during fork regression. The intimate and dynamic SSB-helicase interactions play key roles in ensuring fork regression and DNA replication restart.
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Affiliation(s)
- Piero R Bianco
- Center for Single Molecule Biophysics, University at Buffalo, SUNY, Buffalo, NY 14221, USA
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16
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Wang Y, Sun Z, Bianco PR, Lyubchenko YL. Atomic force microscopy-based characterization of the interaction of PriA helicase with stalled DNA replication forks. J Biol Chem 2020; 295:6043-6052. [PMID: 32209655 DOI: 10.1074/jbc.ra120.013013] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 03/21/2020] [Indexed: 01/31/2023] Open
Abstract
In bacteria, the restart of stalled DNA replication forks requires the DNA helicase PriA. PriA can recognize and remodel abandoned DNA replication forks, unwind DNA in the 3'-to-5' direction, and facilitate the loading of the helicase DnaB onto the DNA to restart replication. Single-stranded DNA-binding protein (SSB) is typically present at the abandoned forks, but it is unclear how SSB and PriA interact, although it has been shown that the two proteins interact both physically and functionally. Here, we used atomic force microscopy to visualize the interaction of PriA with DNA substrates with or without SSB. These experiments were done in the absence of ATP to delineate the substrate recognition pattern of PriA before its ATP-catalyzed DNA-unwinding reaction. These analyses revealed that in the absence of SSB, PriA binds preferentially to a fork substrate with a gap in the leading strand. Such a preference has not been observed for 5'- and 3'-tailed duplexes, suggesting that it is the fork structure that plays an essential role in PriA's selection of DNA substrates. Furthermore, we found that in the absence of SSB, PriA binds exclusively to the fork regions of the DNA substrates. In contrast, fork-bound SSB loads PriA onto the duplex DNA arms of forks, suggesting a remodeling of PriA by SSB. We also demonstrate that the remodeling of PriA requires a functional C-terminal domain of SSB. In summary, our atomic force microscopy analyses reveal key details in the interactions between PriA and stalled DNA replication forks with or without SSB.
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Affiliation(s)
- Yaqing Wang
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, Nebraska 68198-6025
| | - Zhiqiang Sun
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, Nebraska 68198-6025
| | - Piero R Bianco
- Center for Single Molecule Biophysics, University at Buffalo, SUNY, Buffalo, New York 14214
| | - Yuri L Lyubchenko
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, Nebraska 68198-6025.
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17
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Fujiyama S, Abe Y, Shiroishi M, Ikeda Y, Ueda T. Insight into the interaction between PriB and DnaT on bacterial DNA replication restart: Significance of the residues on PriB dimer interface and highly acidic region on DnaT. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2019; 1867:367-375. [DOI: 10.1016/j.bbapap.2019.01.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 01/04/2019] [Accepted: 01/13/2019] [Indexed: 10/27/2022]
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18
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Crystal structure of the C-terminal domain of the primosomal DnaT protein: Insights into a new oligomerization mechanism. Biochem Biophys Res Commun 2019; 511:1-6. [DOI: 10.1016/j.bbrc.2019.02.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 02/03/2019] [Accepted: 02/05/2019] [Indexed: 11/18/2022]
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19
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Structure-specific DNA replication-fork recognition directs helicase and replication restart activities of the PriA helicase. Proc Natl Acad Sci U S A 2018; 115:E9075-E9084. [PMID: 30201718 DOI: 10.1073/pnas.1809842115] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
DNA replication restart, the essential process that reinitiates prematurely terminated genome replication reactions, relies on exquisitely specific recognition of abandoned DNA replication-fork structures. The PriA DNA helicase mediates this process in bacteria through mechanisms that remain poorly defined. We report the crystal structure of a PriA/replication-fork complex, which resolves leading-strand duplex DNA bound to the protein. Interaction with PriA unpairs one end of the DNA and sequesters the 3'-most nucleotide from the nascent leading strand into a conserved protein pocket. Cross-linking studies reveal a surface on the winged-helix domain of PriA that binds to parental duplex DNA. Deleting the winged-helix domain alters PriA's structure-specific DNA unwinding properties and impairs its activity in vivo. Our observations lead to a model in which coordinated parental-, leading-, and lagging-strand DNA binding provide PriA with the structural specificity needed to act on abandoned DNA replication forks.
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20
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Windgassen TA, Wessel SR, Bhattacharyya B, Keck JL. Mechanisms of bacterial DNA replication restart. Nucleic Acids Res 2018; 46:504-519. [PMID: 29202195 PMCID: PMC5778457 DOI: 10.1093/nar/gkx1203] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 11/15/2017] [Accepted: 11/20/2017] [Indexed: 12/21/2022] Open
Abstract
Multi-protein DNA replication complexes called replisomes perform the essential process of copying cellular genetic information prior to cell division. Under ideal conditions, replisomes dissociate only after the entire genome has been duplicated. However, DNA replication rarely occurs without interruptions that can dislodge replisomes from DNA. Such events produce incompletely replicated chromosomes that, if left unrepaired, prevent the segregation of full genomes to daughter cells. To mitigate this threat, cells have evolved 'DNA replication restart' pathways that have been best defined in bacteria. Replication restart requires recognition and remodeling of abandoned replication forks by DNA replication restart proteins followed by reloading of the replicative DNA helicase, which subsequently directs assembly of the remaining replisome subunits. This review summarizes our current understanding of the mechanisms underlying replication restart and the proteins that drive the process in Escherichia coli (PriA, PriB, PriC and DnaT).
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Affiliation(s)
- Tricia A Windgassen
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA
| | - Sarah R Wessel
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA
- Department of Biochemistry, Vanderbilt School of Medicine, Nashville, TN 37205, USA
| | - Basudeb Bhattacharyya
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA
- Department of Chemistry and Biochemistry, University of Wisconsin-La Crosse, La Crosse, WI 54601, USA
| | - James L Keck
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA
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21
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A priA Mutant Expressed in Two Pieces Has Almost Full Activity in Escherichia coli K-12. J Bacteriol 2017; 199:JB.00267-17. [PMID: 28607160 DOI: 10.1128/jb.00267-17] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 06/07/2017] [Indexed: 11/20/2022] Open
Abstract
The ability to restart broken DNA replication forks is essential across all domains of life. In Escherichia coli, the priA, priB, priC, and dnaT genes encode the replication restart proteins (RRPs) to accomplish this task. PriA plays a critical role in replication restart such that its absence reveals a dramatic phenotype: poor growth, high basal levels of SOS expression, poorly partitioned nucleoids (Par-), UV sensitivity, and recombination deficiency (Rec-). PriA has 733 amino acids, and its structure is composed of six domains that enable it to bind to DNA replication fork-like structures, remodel the strands of DNA, interact with SSB (single-stranded DNA binding protein), PriB, and DnaT, and display ATPase, helicase, and translocase activities. We have characterized a new priA mutation called priA316::cat It is a composite mutation involving an insertion that truncates the protein within the winged-helix domain (at the 154th codon) and an ACG (Thr)-to-ATG (Met) mutation that allows reinitiation of translation at the 157th codon such that PriA is expressed in two pieces. priA316::cat phenotypes are like those of the wild type for growth, recombination, and UV resistance, revealing only a slightly increased level of SOS expression and defects in nucleoid partitioning in the mutant. Both parts of PriA are required for activity, and the N-terminal fragment can be optimized to yield wild-type activity. A deletion of the lon protease suppresses priA316::cat phenotypes. We hypothesize the two parts of PriA form a complex that supplies most of the PriA activity needed in the cell.IMPORTANCE PriA is a highly conserved multifunctional protein that plays a crucial role in the essential process of replication restart. Here we characterize an insertion mutation of priA with an intragenic suppressor such that it is now made in two parts. These two pieces split the winged-helix domain to separate the N-terminal 3' DNA-binding domain from the C-terminal domain of PriA. It is hypothesized that the two pieces form a complex that is capable of almost wild type priA function. The composite mutation leads to a moderate level of SOS expression and defects in partitioning of the chromosomes. Full function is restored by deletion of lon, suggesting that stability of this complex may be a reason for the partial phenotypes seen.
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Abstract
In bacteria, replication forks assembled at a replication origin travel to the terminus, often a few megabases away. They may encounter obstacles that trigger replisome disassembly, rendering replication restart from abandoned forks crucial for cell viability. During the past 25 years, the genes that encode replication restart proteins have been identified and genetically characterized. In parallel, the enzymes were purified and analyzed in vitro, where they can catalyze replication initiation in a sequence-independent manner from fork-like DNA structures. This work also revealed a close link between replication and homologous recombination, as replication restart from recombination intermediates is an essential step of DNA double-strand break repair in bacteria and, conversely, arrested replication forks can be acted upon by recombination proteins and converted into various recombination substrates. In this review, we summarize this intense period of research that led to the characterization of the ubiquitous replication restart protein PriA and its partners, to the definition of several replication restart pathways in vivo, and to the description of tight links between replication and homologous recombination, responsible for the importance of replication restart in the maintenance of genome stability.
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Remodeling and Control of Homologous Recombination by DNA Helicases and Translocases that Target Recombinases and Synapsis. Genes (Basel) 2016; 7:genes7080052. [PMID: 27548227 PMCID: PMC4999840 DOI: 10.3390/genes7080052] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 07/24/2016] [Accepted: 08/12/2016] [Indexed: 11/16/2022] Open
Abstract
Recombinase enzymes catalyse invasion of single-stranded DNA (ssDNA) into homologous duplex DNA forming "Displacement loops" (D-loops), a process called synapsis. This triggers homologous recombination (HR), which can follow several possible paths to underpin DNA repair and restart of blocked and collapsed DNA replication forks. Therefore, synapsis can be a checkpoint for controlling whether or not, how far, and by which pathway, HR proceeds to overcome an obstacle or break in a replication fork. Synapsis can be antagonized by limiting access of a recombinase to ssDNA and by dissociation of D-loops or heteroduplex formed by synapsis. Antagonists include DNA helicases and translocases that are identifiable in eukaryotes, bacteria and archaea, and which target synaptic and pre-synaptic DNA structures thereby controlling HR at early stages. Here we survey these events with emphasis on enabling DNA replication to be resumed from sites of blockage or collapse. We also note how knowledge of anti-recombination activities could be useful to improve efficiency of CRISPR-based genome editing.
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Windgassen TA, Keck JL. An aromatic-rich loop couples DNA binding and ATP hydrolysis in the PriA DNA helicase. Nucleic Acids Res 2016; 44:9745-9757. [PMID: 27484483 PMCID: PMC5175346 DOI: 10.1093/nar/gkw690] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 07/25/2016] [Accepted: 07/26/2016] [Indexed: 11/13/2022] Open
Abstract
Helicases couple ATP hydrolysis to nucleic acid binding and unwinding via molecular mechanisms that remain poorly defined for most enzyme subfamilies within the superfamily 2 (SF2) helicase group. A crystal structure of the PriA SF2 DNA helicase, which governs restart of prematurely terminated replication processes in bacteria, revealed the presence of an aromatic-rich loop (ARL) on the presumptive DNA-binding surface of the enzyme. The position and sequence of the ARL was similar to loops known to couple ATP hydrolysis with DNA binding in a subset of other SF2 enzymes, however, the roles of the ARL in PriA had not been investigated. Here, we show that changes within the ARL sequence uncouple PriA ATPase activity from DNA binding. In vitro protein-DNA crosslinking experiments define a residue- and nucleotide-specific interaction map for PriA, showing that the ARL binds replication fork junctions whereas other sites bind the leading or lagging strands. We propose that DNA binding to the ARL allosterically triggers ATP hydrolysis in PriA. Additional SF2 helicases with similarly positioned loops may also couple DNA binding to ATP hydrolysis using related mechanisms.
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Affiliation(s)
- Tricia A Windgassen
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA
| | - James L Keck
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA
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25
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Huang YH, Lien Y, Huang CC, Huang CY. Characterization of Staphylococcus aureus Primosomal DnaD Protein: Highly Conserved C-Terminal Region Is Crucial for ssDNA and PriA Helicase Binding but Not for DnaA Protein-Binding and Self-Tetramerization. PLoS One 2016; 11:e0157593. [PMID: 27304067 PMCID: PMC4909229 DOI: 10.1371/journal.pone.0157593] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 06/01/2016] [Indexed: 11/18/2022] Open
Abstract
The role of DnaD in the recruitment of replicative helicase has been identified. However, knowledge of the DNA, PriA, and DnaA binding mechanism of this protein for the DnaA- and PriA-directed replication primosome assemblies is limited. We characterized the DNA-binding properties of DnaD from Staphylococcus aureus (SaDnaD) and analyzed its interactions with SaPriA and SaDnaA. The gel filtration chromatography analysis of purified SaDnaD and its deletion mutant proteins (SaDnaD1-195, SaDnaD1-200 and SaDnaD1-204) showed a stable tetramer in solution. This finding indicates that the C-terminal region aa 196-228 is not crucial for SaDnaD oligomerization. SaDnaD forms distinct complexes with ssDNA of different lengths. In fluorescence titrations, SaDnaD bound to ssDNA with a binding-site size of approximately 32 nt. A stable complex of SaDnaD1-195, SaDnaD1-200, and SaDnaD1-204 with ssDNA dT40 was undetectable, indicating that the C-terminal region of SaDnaD (particularly aa 205-228) is crucial for ssDNA binding. The SPR results revealed that SaDnaD1-195 can interact with SaDnaA but not with SaPriA, which may indicate that DnaD has different binding sites for PriA and DnaA. Both SaDnaD and SaDnaDY176A mutant proteins, but not SaDnaD1-195, can significantly stimulate the ATPase activity of SaPriA. Hence, the stimulation effect mainly resulted from direct contact within the protein-protein interaction, not via the DNA-protein interaction. Kinetic studies revealed that the SaDnaD-SaPriA interaction increases the Vmax of the SaPriA ATPase fivefold without significantly affecting the Km. These results indicate that the conserved C-terminal region is crucial for ssDNA and PriA helicase binding, but not for DnaA protein-binding and self-tetramerization.
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Affiliation(s)
- Yen-Hua Huang
- School of Biomedical Sciences, Chung Shan Medical University, No.110, Sec.1, Chien-Kuo N. Rd., Taichung City, Taiwan
| | - Yi Lien
- School of Biomedical Sciences, Chung Shan Medical University, No.110, Sec.1, Chien-Kuo N. Rd., Taichung City, Taiwan
| | - Chien-Chih Huang
- School of Biomedical Sciences, Chung Shan Medical University, No.110, Sec.1, Chien-Kuo N. Rd., Taichung City, Taiwan
| | - Cheng-Yang Huang
- School of Biomedical Sciences, Chung Shan Medical University, No.110, Sec.1, Chien-Kuo N. Rd., Taichung City, Taiwan
- Department of Medical Research, Chung Shan Medical University Hospital, No.110, Sec.1, Chien-Kuo N. Rd., Taichung City, Taiwan
- * E-mail:
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26
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Tanaka T, Nishito Y, Masai H. Fork restart protein, PriA, binds around oriC after depletion of nucleotide precursors: Replication fork arrest near the replication origin. Biochem Biophys Res Commun 2016; 470:546-551. [PMID: 26801562 DOI: 10.1016/j.bbrc.2016.01.108] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Accepted: 01/17/2016] [Indexed: 11/19/2022]
Abstract
Arrest of replication fork progression is one of the most common causes for increasing the genomic instability. In bacteria, PriA, a conserved DEXH-type helicase, plays a major role in recognition of the stalled forks and restart of DNA replication. We took advantage of PriA's ability to specifically recognize stalled replication forks to determine the genomic loci where replication forks are prone to stall on the Escherichia coli genome. We found that PriA binds around oriC upon thymine starvation which reduces the nucleotide supply and causes replication fork stalling. PriA binding quickly disappeared upon readdition of thymine. Furthermore, BrdU was incorporated at around oriC upon release from thymine starvation. Our results indicate that reduced supply of DNA replication precursors causes replication fork stalling preferentially in the 600 kb segment centered at oriC. This suggests that replication of the vicinity of oriC requires higher level of nucleotide precursors. The results also point to a possibility of slow fork movement and/or the presence of multiple fork arrest signals within this segment. Indeed, we have identified rather strong fork stall/pausing signals symmetrically located at ∼50 kb away from oriC. We speculate that replication pausing and fork-slow-down shortly after initiation may represent a novel checkpoint that ensures the presence of sufficient nucleotide supply prior to commitment to duplication of the entire genome.
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Affiliation(s)
- Taku Tanaka
- Department of Genome Medicine, Tokyo Metropolitan Institute of Medical Science, 4-6-1 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan
| | - Yasumasa Nishito
- Basic Technology Research Center, Tokyo Metropolitan Institute of Medical Science, 4-6-1 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan
| | - Hisao Masai
- Department of Genome Medicine, Tokyo Metropolitan Institute of Medical Science, 4-6-1 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
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27
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Ivančić-Baće I, Cass SD, Wearne SJ, Bolt EL. Different genome stability proteins underpin primed and naïve adaptation in E. coli CRISPR-Cas immunity. Nucleic Acids Res 2015; 43:10821-30. [PMID: 26578567 PMCID: PMC4678826 DOI: 10.1093/nar/gkv1213] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Accepted: 10/28/2015] [Indexed: 12/18/2022] Open
Abstract
CRISPR-Cas is a prokaryotic immune system built from capture and integration of invader DNA into CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) loci, termed 'Adaptation', which is dependent on Cas1 and Cas2 proteins. In Escherichia coli, Cascade-Cas3 degrades invader DNA to effect immunity, termed 'Interference'. Adaptation can interact with interference ('primed'), or is independent of it ('naïve'). We demonstrate that primed adaptation requires the RecG helicase and PriA protein to be present. Genetic analysis of mutant phenotypes suggests that RecG is needed to dissipate R-loops at blocked replication forks. Additionally, we identify that DNA polymerase I is important for both primed and naive adaptation, and that RecB is needed for naïve adaptation. Purified Cas1-Cas2 protein shows specificity for binding to and nicking forked DNA within single strand gaps, and collapsing forks into DNA duplexes. The data suggest that different genome stability systems interact with primed or naïve adaptation when responding to blocked or collapsed invader DNA replication. In this model, RecG and Cas3 proteins respond to invader DNA replication forks that are blocked by Cascade interference, enabling DNA capture. RecBCD targets DNA ends at collapsed forks, enabling DNA capture without interference. DNA polymerase I is proposed to fill DNA gaps during spacer integration.
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Affiliation(s)
- Ivana Ivančić-Baće
- Faculty of Science, Department of Molecular Biology, University of Zagreb, Horvatovac 102a, Zagreb, Croatia
| | - Simon D Cass
- School of Life Sciences, Queen's Medical Centre, University of Nottingham, NG72UH, UK
| | - Stephen J Wearne
- School of Life Sciences, Queen's Medical Centre, University of Nottingham, NG72UH, UK
| | - Edward L Bolt
- School of Life Sciences, Queen's Medical Centre, University of Nottingham, NG72UH, UK
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28
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Kile AC, Chavez DA, Bacal J, Eldirany S, Korzhnev DM, Bezsonova I, Eichman BF, Cimprich KA. HLTF's Ancient HIRAN Domain Binds 3' DNA Ends to Drive Replication Fork Reversal. Mol Cell 2015; 58:1090-100. [PMID: 26051180 DOI: 10.1016/j.molcel.2015.05.013] [Citation(s) in RCA: 151] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 04/29/2015] [Accepted: 05/01/2015] [Indexed: 12/20/2022]
Abstract
Stalled replication forks are a critical problem for the cell because they can lead to complex genome rearrangements that underlie cell death and disease. Processes such as DNA damage tolerance and replication fork reversal protect stalled forks from these events. A central mediator of these DNA damage responses in humans is the Rad5-related DNA translocase, HLTF. Here, we present biochemical and structural evidence that the HIRAN domain, an ancient and conserved domain found in HLTF and other DNA processing proteins, is a modified oligonucleotide/oligosaccharide (OB) fold that binds to 3' ssDNA ends. We demonstrate that the HIRAN domain promotes HLTF-dependent fork reversal in vitro through its interaction with 3' ssDNA ends found at forks. Finally, we show that HLTF restrains replication fork progression in cells in a HIRAN-dependent manner. These findings establish a mechanism of HLTF-mediated fork reversal and provide insight into the requirement for distinct fork remodeling activities in the cell.
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Affiliation(s)
- Andrew C Kile
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Diana A Chavez
- Department of Biological Sciences and Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Julien Bacal
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Sherif Eldirany
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT 06032, USA
| | - Dmitry M Korzhnev
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT 06032, USA
| | - Irina Bezsonova
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT 06032, USA
| | - Brandt F Eichman
- Department of Biological Sciences and Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA.
| | - Karlene A Cimprich
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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29
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Manhart CM, McHenry CS. Identification of Subunit Binding Positions on a Model Fork and Displacements That Occur during Sequential Assembly of the Escherichia coli Primosome. J Biol Chem 2015; 290:10828-39. [PMID: 25745110 DOI: 10.1074/jbc.m115.642066] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Indexed: 11/06/2022] Open
Abstract
When replication stalls and forks disassemble, the restart primosome is required to reload the replicative helicase so that chromosomal replication can be reinitiated. We have taken a photo-cross-linking approach, using model replication forks containing a phenyl diazirine placed at single locations, to determine the positions of primosomal protein binding and changes in interactions that occur during the assembly reaction. This approach revealed a novel mode for single-stranded DNA-binding protein (SSB)-DNA binding, in which SSB interacts with both the leading and lagging single-strand segments and the parental duplex of the fork. Cross-linking to a novel region within SSB is observed only when it is bound to forked structures. This binding mode is also followed by PriB. PriA binds to the fork, excluding SSB and PriB, interacting with the primer terminus, single-stranded leading and lagging strands and duplex in immediate proximity of the fork. SSB binds to flanking single-stranded segments distal to the fork in the presence of PriA. The addition of PriB or DnaT to a PriA-SSB-fork complex does not lead to cross-linking or displacement, suggesting that their association is through protein-protein interactions at early stages of the reaction. Upon addition of DnaC and the DnaB helicase in the presence of ATPγS, helicase is assembled, leading to contacts within the duplex region on the tracking (lagging) strand and strong contacts with the displaced leading single strand near the fork. PriA is displaced from DNA upon helicase assembly.
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Affiliation(s)
- Carol M Manhart
- From the Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80303
| | - Charles S McHenry
- From the Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80303
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30
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Aramaki T, Abe Y, Furutani K, Katayama T, Ueda T. Basic and aromatic residues in the C-terminal domain of PriC are involved in ssDNA and SSB binding. ACTA ACUST UNITED AC 2015; 157:529-37. [DOI: 10.1093/jb/mvv014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 12/30/2014] [Indexed: 11/12/2022]
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Fujiyama S, Abe Y, Tani J, Urabe M, Sato K, Aramaki T, Katayama T, Ueda T. Structure and mechanism of the primosome protein DnaT- functional structures for homotrimerization, dissociation of ssDNA from the PriB·ssDNA complex, and formation of the DnaT·ssDNA complex. FEBS J 2014; 281:5356-70. [DOI: 10.1111/febs.13080] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 09/20/2014] [Accepted: 09/24/2014] [Indexed: 12/31/2022]
Affiliation(s)
- Saki Fujiyama
- Department of Protein Structure, Function and Design; Graduate School of Pharmaceutical Sciences; Kyushu University; Fukuoka Japan
| | - Yoshito Abe
- Department of Protein Structure, Function and Design; Graduate School of Pharmaceutical Sciences; Kyushu University; Fukuoka Japan
| | - Junya Tani
- Department of Protein Structure, Function and Design; Graduate School of Pharmaceutical Sciences; Kyushu University; Fukuoka Japan
| | - Masashi Urabe
- Department of Protein Structure, Function and Design; Graduate School of Pharmaceutical Sciences; Kyushu University; Fukuoka Japan
| | - Kenji Sato
- Department of Protein Structure, Function and Design; Graduate School of Pharmaceutical Sciences; Kyushu University; Fukuoka Japan
| | - Takahiko Aramaki
- Department of Protein Structure, Function and Design; Graduate School of Pharmaceutical Sciences; Kyushu University; Fukuoka Japan
| | - Tsutomu Katayama
- Department of Molecular Biology; Graduate School of Pharmaceutical Sciences; Kyushu University; Fukuoka Japan
| | - Tadashi Ueda
- Department of Protein Structure, Function and Design; Graduate School of Pharmaceutical Sciences; Kyushu University; Fukuoka Japan
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32
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Soultanas P. The replication-transcription conflict. Transcription 2014; 2:140-144. [PMID: 21826285 DOI: 10.4161/trns.2.3.15908] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Accepted: 04/24/2011] [Indexed: 01/21/2023] Open
Abstract
In response to environmental and nutritional stimuli, a whole array of proteins remodel genome architecture, activate or transcribe genes, suppress genes, repair lesions and base-modifications, faithfully replicate and safely separate the parental and daughter genomes during cell division. Negotiating and resolving conflicts of genome trafficking is essential for genome stability.
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Affiliation(s)
- Panos Soultanas
- Centre for Biomolecular Sciences; School of Chemistry; University Park; University of Nottingham; Nottingham, UK
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Liu Z, Chen P, Wang X, Cai G, Niu L, Teng M, Li X. Crystal structure of DnaT84-153-dT10 ssDNA complex reveals a novel single-stranded DNA binding mode. Nucleic Acids Res 2014; 42:9470-83. [PMID: 25053836 PMCID: PMC4132743 DOI: 10.1093/nar/gku633] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
DnaT is a primosomal protein that is required for the stalled replication fork restart in Escherichia coli. As an adapter, DnaT mediates the PriA-PriB-ssDNA ternary complex and the DnaB/C complex. However, the fundamental function of DnaT during PriA-dependent primosome assembly is still a black box. Here, we report the 2.83 Å DnaT84–153-dT10 ssDNA complex structure, which reveals a novel three-helix bundle single-stranded DNA binding mode. Based on binding assays and negative-staining electron microscopy results, we found that DnaT can bind to phiX 174 ssDNA to form nucleoprotein filaments for the first time, which indicates that DnaT might function as a scaffold protein during the PriA-dependent primosome assembly. In combination with biochemical analysis, we propose a cooperative mechanism for the binding of DnaT to ssDNA and a possible model for the assembly of PriA-PriB-ssDNA-DnaT complex that sheds light on the function of DnaT during the primosome assembly and stalled replication fork restart. This report presents the first structure of the DnaT C-terminal complex with ssDNA and a novel model that explains the interactions between the three-helix bundle and ssDNA.
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Affiliation(s)
- Zheng Liu
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China Key Laboratory of Structural Biology, Chinese Academy of Sciences, Hefei, Anhui 230026, People's Republic of China
| | - Peng Chen
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China Key Laboratory of Structural Biology, Chinese Academy of Sciences, Hefei, Anhui 230026, People's Republic of China
| | - Xuejuan Wang
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China Key Laboratory of Structural Biology, Chinese Academy of Sciences, Hefei, Anhui 230026, People's Republic of China
| | - Gang Cai
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China Key Laboratory of Structural Biology, Chinese Academy of Sciences, Hefei, Anhui 230026, People's Republic of China
| | - Liwen Niu
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China Key Laboratory of Structural Biology, Chinese Academy of Sciences, Hefei, Anhui 230026, People's Republic of China
| | - Maikun Teng
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China Key Laboratory of Structural Biology, Chinese Academy of Sciences, Hefei, Anhui 230026, People's Republic of China
| | - Xu Li
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China Key Laboratory of Structural Biology, Chinese Academy of Sciences, Hefei, Anhui 230026, People's Republic of China
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Structural insight into the DNA-binding mode of the primosomal proteins PriA, PriB, and DnaT. BIOMED RESEARCH INTERNATIONAL 2014; 2014:195162. [PMID: 25136561 PMCID: PMC4129139 DOI: 10.1155/2014/195162] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 06/20/2014] [Accepted: 07/01/2014] [Indexed: 01/31/2023]
Abstract
Replication restart primosome is a complex dynamic system that is essential for bacterial survival. This system uses various proteins to reinitiate chromosomal DNA replication to maintain genetic integrity after DNA damage. The replication restart primosome in Escherichia coli is composed of PriA helicase, PriB, PriC, DnaT, DnaC, DnaB helicase, and DnaG primase. The assembly of the protein complexes within the forked DNA responsible for reloading the replicative DnaB helicase anywhere on the chromosome for genome duplication requires the coordination of transient biomolecular interactions. Over the last decade, investigations on the structure and mechanism of these nucleoproteins have provided considerable insight into primosome assembly. In this review, we summarize and discuss our current knowledge and recent advances on the DNA-binding mode of the primosomal proteins PriA, PriB, and DnaT.
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35
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Abstract
Collisions between cellular DNA replication machinery (replisomes) and damaged DNA or immovable protein complexes can dissociate replisomes before the completion of replication. This potentially lethal problem is resolved by cellular "replication restart" reactions that recognize the structures of prematurely abandoned replication forks and mediate replisomal reloading. In bacteria, this essential activity is orchestrated by the PriA DNA helicase, which identifies replication forks via structure-specific DNA binding and interactions with fork-associated ssDNA-binding proteins (SSBs). However, the mechanisms by which PriA binds replication fork DNA and coordinates subsequent replication restart reactions have remained unclear due to the dearth of high-resolution structural information available for the protein. Here, we describe the crystal structures of full-length PriA and PriA bound to SSB. The structures reveal a modular arrangement for PriA in which several DNA-binding domains surround its helicase core in a manner that appears to be poised for binding to branched replication fork DNA structures while simultaneously allowing complex formation with SSB. PriA interaction with SSB is shown to modulate SSB/DNA complexes in a manner that exposes a potential replication initiation site. From these observations, a model emerges to explain how PriA links recognition of diverse replication forks to replication restart.
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36
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Masai H. A personal reflection on the replicon theory: from R1 plasmid to replication timing regulation in human cells. J Mol Biol 2013; 425:4663-72. [PMID: 23579064 DOI: 10.1016/j.jmb.2013.03.039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 03/15/2013] [Accepted: 03/21/2013] [Indexed: 01/09/2023]
Abstract
Fifty years after the Replicon Theory was originally presented, detailed mechanistic insight into prokaryotic replicons has been obtained and rapid progress is being made to elucidate the more complex regulatory mechanisms of replicon regulation in eukaryotic cells. Here, I present my personal perspectives on how studies of model replicons have contributed to our understanding of the basic mechanisms of DNA replication as well as the evolution of replication regulation in human cells. I will also discuss how replication regulation contributes to the stable maintenance of the genome and how disruption of replication regulation leads to human diseases.
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Affiliation(s)
- Hisao Masai
- Department of Genome Medicine, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamkitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
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37
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Huang YH, Huang CY. The N-terminal domain of DnaT, a primosomal DNA replication protein, is crucial for PriB binding and self-trimerization. Biochem Biophys Res Commun 2013; 442:147-52. [PMID: 24280305 DOI: 10.1016/j.bbrc.2013.11.069] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 11/16/2013] [Indexed: 10/26/2022]
Abstract
DnaT and PriB are replication restart primosomal proteins required for re-initiating chromosomal DNA replication in bacteria. Although the interaction of DnaT with PriB has been proposed, which region of DnaT is involved in PriB binding and self-trimerization remains unknown. In this study, we identified the N-terminal domain in DnaT (aa 1-83) that is important in PriB binding and self-trimerization but not in single-stranded DNA (ssDNA) binding. DnaT and the deletion mutant DnaT42-179 protein can bind to PriB according to native polyacrylamide gel electrophoresis, Western blot analysis, and pull-down assay, whereas DnaT84-179 cannot bind to PriB. In contrast to DnaT, DnaT26-179, and DnaT42-179 proteins, which form distinct complexes with ssDNA of different lengths, DnaT84-179 forms only a single complex with ssDNA. Analysis of DnaT84-179 protein by gel filtration chromatography showed a stable monomer in solution rather than a trimer, such as DnaT, DnaT26-179, and DnaT42-179 proteins. These results constitute a pioneering study of the domain definition of DnaT. Further research can directly focus on determining how DnaT binds to the PriA-PriB-DNA tricomplex in replication restart by the hand-off mechanism.
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Affiliation(s)
- Yen-Hua Huang
- School of Biomedical Sciences, Chung Shan Medical University, No. 110, Sec. 1, Chien-Kuo N. Rd., Taichung City, Taiwan
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38
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Fujiyama S, Abe Y, Takenawa T, Aramaki T, Shioi S, Katayama T, Ueda T. Involvement of histidine in complex formation of PriB and single-stranded DNA. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2013; 1844:299-307. [PMID: 24200676 DOI: 10.1016/j.bbapap.2013.10.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 10/26/2013] [Accepted: 10/28/2013] [Indexed: 10/26/2022]
Abstract
PriB is a basic 10-kDa protein that acts as a facilitator in PriA-dependent replication restart in Escherichia coli. PriB has an OB-fold dimer structure and exhibits single-stranded DNA (ssDNA)-binding activities similar to single-stranded binding protein (SSB). In this study, we examined PriB's interaction with ssDNA (oligo-dT35, -dT15, and -dT7) using heteronuclear NMR analysis. Interestingly, (1)H or (15)N chemical shift changes of the PriB main-chain showed two distinct modes using oligo-dT35. The chemical shift perturbation sites in the primary mode were consistent with the main contact site in PriB-ssDNA, which was previously determined by crystal structure analysis. The results also suggested that approximately 8nt in ssDNA was the main contact site to PriB. In the secondary mode, residues in the α-helix region (His57-Ser65) and in β4-loop3-β5 were mainly perturbed. On the other hand, we examined the state of ssDNA by FRET using 5'-Cy3- and 3'-Cy5-modified oligo-dT35. As the PriB concentration increased, two-step saturation curves were observed in the FRET assay, suggesting a compact structure of ssDNA. Moreover, we confirmed two-step PriB binding to oligo-dT35 using EMSA. The pH dependence of FRET suggested contribution of the His residues. Therefore, we prepared His mutants of PriB and found that His64 in the α-helix region contributed to the second interaction between PriB and ssDNA using FRET and EMSA. Thus, from a structural standpoint, we suggested the role of His64 on the compactness of the PriB-ssDNA complex and on the positive cooperativity of PriB.
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Affiliation(s)
- Saki Fujiyama
- Laboratory of Protein Structure, Function and Design, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Yoshito Abe
- Laboratory of Protein Structure, Function and Design, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Taichi Takenawa
- Laboratory of Protein Structure, Function and Design, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Takahiko Aramaki
- Laboratory of Protein Structure, Function and Design, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Seijiro Shioi
- Radioisotope Center, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Tadashi Ueda
- Laboratory of Protein Structure, Function and Design, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
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39
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Huang YH, Lin MJ, Huang CY. DnaT is a single-stranded DNA binding protein. Genes Cells 2013; 18:1007-19. [PMID: 24118681 DOI: 10.1111/gtc.12095] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 08/11/2013] [Indexed: 01/26/2023]
Abstract
DnaT is one of the replication restart primosomal proteins required for reinitiating chromosomal DNA replication in bacteria. In this study, we identified and characterized the single-stranded DNA (ssDNA)-binding properties of DnaT using electrophoretic mobility shift analysis (EMSA), bioinformatic tools and two deletion mutant proteins, namely, DnaT26-179 and DnaT42-179. ConSurf analysis indicated that the N-terminal region of DnaT is highly variable. The analysis of purified DnaT and the deletion mutant protein DnaT42-179 by gel filtration chromatography showed a stable trimer in solution, indicating that the N-terminal region, amino acid 1-41, is not crucial for the oligomerization of DnaT. Contrary to PriB, which forms a single complex with a series of ssDNA homopolymers, DnaT, DnaT26-179 and DnaT42-179 form distinct complexes with ssDNA of different lengths and the size of binding site of 26 ± 2 nucleotides (nt). Using bioinformatic programs (ps)(2) and the analysis of the positively charged/hydrophobic residue distribution, as well as the biophysical results in this study, we propose a binding model for the DnaT trimer-ssDNA complex, in which 25-nt-long ssDNA is tethered on the surface groove located in the highly conserved C-terminal domain of DnaT. These results constitute the first study regarding ssDNA-binding activity of DnaT. Consequently, a hand-off mechanism for primosome assembly was modified.
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Affiliation(s)
- Yen-Hua Huang
- School of Biomedical Sciences, Chung Shan Medical University, No. 110, Sec. 1, Chien-Kuo N. Rd, Taichung, Taiwan
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40
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Yeast Two-Hybrid Analysis of PriB-Interacting Proteins in Replication Restart Primosome: A Proposed PriB–SSB Interaction Model. Protein J 2013; 32:477-83. [DOI: 10.1007/s10930-013-9509-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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41
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Abd Wahab S, Choi M, Bianco PR. Characterization of the ATPase activity of RecG and RuvAB proteins on model fork structures reveals insight into stalled DNA replication fork repair. J Biol Chem 2013; 288:26397-409. [PMID: 23893472 DOI: 10.1074/jbc.m113.500223] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
RecG and RuvAB are proposed to act at stalled DNA replication forks to facilitate replication restart. To clarify the roles of these proteins in fork regression, we used a coupled spectrophotometric ATPase assay to determine how these helicases act on two groups of model fork substrates: the first group mimics nascent stalled forks, whereas the second mimics regressed fork structures. The results show that RecG is active on the substrates in group 1, whereas these are poor substrates for RuvAB. In addition, in the presence of group 1 forks, the single-stranded DNA-binding protein (SSB) enhances the activity of RecG and enables it to compete with excess RuvA. In contrast, SSB inhibits the activity of RuvAB on these substrates. Results also show that the preferred regressed fork substrate for RuvAB is a Holliday junction, not a forked DNA. The active form of the enzyme on the Holliday junction contains a single RuvA tetramer. In contrast, although the enzyme is active on a regressed fork structure, RuvB loading by a single RuvA tetramer is impaired, and full activity requires the cooperative binding of two forked DNA substrate molecules. Collectively, the data support a model where RecG is responsible for stalled DNA replication fork regression. SSB ensures that if the nascent fork has single-stranded DNA character RuvAB is inhibited, whereas the activity of RecG is preferentially enhanced. Only once the fork has been regressed and the DNA is relaxed can RuvAB bind to a RecG-extruded Holliday junction.
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42
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Aramaki T, Abe Y, Ohkuri T, Mishima T, Yamashita S, Katayama T, Ueda T. Domain separation and characterization of PriC, a replication restart primosome factor in Escherichia coli. Genes Cells 2013; 18:723-32. [PMID: 23819889 DOI: 10.1111/gtc.12069] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Accepted: 05/02/2013] [Indexed: 01/09/2023]
Abstract
In Escherichia coli the oriC-independent primosome plays an essential role in replication restart after dissociation of the replication DNA-protein complex by DNA damage. Primosome is thought to form via two pathways: one PriA dependent and the other PriA independent. PriC is a key protein in the replication restart of the PriA-independent pathway. In this study, we determined that PriC was divided into two domains. Then, we obtained information that: (i) the C-terminal domain preferentially binds to single-stranded DNA (ssDNA); (ii) the binding of PriC to ssDNA depends on salt concentration; and (iii) the binding site size of PriC is approximately 7-9 nucleotides. The protease digestion of PriC suggested that a possible DNA-binding site is the N-terminus of the C-terminal domain where basic amino acid residues are concentrated. Interestingly, α-helical induction of the C-terminal domain of PriC occurred after the addition of DNAs. Also, we examined the role of heptad repeat of leucine or valine residues in the C-terminal domain and PriC oligomerization. This study describes the structure and function analysis of PriC which forms the primosome complex in replication restart.
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Affiliation(s)
- Takahiko Aramaki
- Department of Protein Structure, Function and Design, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
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43
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Wessel SR, Marceau AH, Massoni SC, Zhou R, Ha T, Sandler SJ, Keck JL. PriC-mediated DNA replication restart requires PriC complex formation with the single-stranded DNA-binding protein. J Biol Chem 2013; 288:17569-78. [PMID: 23629733 DOI: 10.1074/jbc.m113.478156] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Frequent collisions between cellular DNA replication complexes (replisomes) and obstacles such as damaged DNA or frozen protein complexes make DNA replication fork progression surprisingly sporadic. These collisions can lead to the ejection of replisomes prior to completion of replication, which, if left unrepaired, results in bacterial cell death. As such, bacteria have evolved DNA replication restart mechanisms that function to reload replisomes onto abandoned DNA replication forks. Here, we define a direct interaction between PriC, a key Escherichia coli DNA replication restart protein, and the single-stranded DNA-binding protein (SSB), a protein that is ubiquitously associated with DNA replication forks. PriC/SSB complex formation requires evolutionarily conserved residues from both proteins, including a pair of Arg residues from PriC and the C terminus of SSB. In vitro, disruption of the PriC/SSB interface by sequence changes in either protein blocks the first step of DNA replication restart, reloading of the replicative DnaB helicase onto an abandoned replication fork. Consistent with the critical role of PriC/SSB complex formation in DNA replication restart, PriC variants that cannot bind SSB are non-functional in vivo. Single-molecule experiments demonstrate that PriC binding to SSB alters SSB/DNA complexes, exposing single-stranded DNA and creating a platform for other proteins to bind. These data lead to a model in which PriC interaction with SSB remodels SSB/DNA structures at abandoned DNA replication forks to create a DNA structure that is competent for DnaB loading.
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Affiliation(s)
- Sarah R Wessel
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706, USA
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44
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Abstract
Helicases are fundamental components of all replication complexes since unwinding of the double-stranded template to generate single-stranded DNA is essential to direct DNA synthesis by polymerases. However, helicases are also required in many other steps of DNA replication. Replicative helicases not only unwind the template DNA but also play key roles in regulating priming of DNA synthesis and coordination of leading and lagging strand DNA polymerases. Accessory helicases also aid replicative helicases in unwinding of the template strands in the presence of proteins bound to the DNA, minimising the risks posed by nucleoprotein complexes to continued fork movement. Helicases also play critical roles in Okazaki fragment processing in eukaryotes and may also be needed to minimise topological problems when replication forks converge. Thus fork movement, coordination of DNA synthesis, lagging strand maturation and termination of replication all depend on helicases. Moreover, if disaster strikes and a replication fork breaks down then reloading of the replication machinery is effected by helicases, at least in bacteria. This chapter describes how helicases function in these multiple steps at the fork and how DNA unwinding is coordinated with other catalytic processes to ensure efficient, high fidelity duplication of the genetic material in all organisms.
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Affiliation(s)
- Peter McGlynn
- Department of Biology, University of York, York, Yorkshire, UK,
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45
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Szymanski MR, Bujalowski PJ, Jezewska MJ, Gmyrek AM, Bujalowski W. The N-terminal domain of the Escherichia coli PriA helicase contains both the DNA- and nucleotide-binding sites. Energetics of domain--DNA interactions and allosteric effect of the nucleotide cofactors. Biochemistry 2011; 50:9167-83. [PMID: 21888358 DOI: 10.1021/bi201100k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Functional interactions of the Escherichia coli PriA helicase 181N-terminal domain with the DNA and nucleotide cofactors have been quantitatively examined. The isolated 181N-terminal domain forms a stable dimer in solution, most probably reflecting the involvement of the domain in specific cooperative interactions of the intact PriA protein--double-stranded DNA (dsDNA) complex. Only one monomer of the domain dimer binds the DNA; i.e., the dimer has one effective DNA-binding site. Although the total site size of the dimer--single-stranded DNA (ssDNA) complex is ~13 nucleotides, the DNA-binding subsite engages in direct interactions with approximately five nucleotides. A small number of interacting nucleotides indicates that the DNA-binding subsites of the PriA helicase, i.e., the strong subsite on the helicase domain and the weak subsite on the N-terminal domain, are spatially separated in the intact enzyme. Contrary to current views, the subsite has an only slight preference for the 3'-end OH group of the ssDNA and lacks any significant base specificity, although it has a significant dsDNA affinity. Unlike the intact helicase, the DNA-binding subsite of the isolated domain is in an open conformation, indicating the presence of the direct helicase domain--N-terminal domain interactions. The discovery that the 181N-terminal domain possesses a nucleotide-binding site places the allosteric, weak nucleotide-binding site of the intact PriA on the N-terminal domain. The specific effect of ADP on the domain DNA-binding subsite indicates that in the intact helicase, the bound ADP not only opens the DNA-binding subsite but also increases its intrinsic DNA affinity.
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Affiliation(s)
- Michal R Szymanski
- Department of Biochemistry and Molecular Biology, Department of Obstetrics and Gynecology, The Sealy Center for Structural Biology, and The Sealy Center for Cancer Cell Biology, The University of Texas Medical Branch at Galveston, Galveston, Texas 77555-1053, United States
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46
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Feng C, Sunchu B, Greenwood ME, Lopper ME. A bacterial PriB with weak single-stranded DNA binding activity can stimulate the DNA unwinding activity of its cognate PriA helicase. BMC Microbiol 2011; 11:189. [PMID: 21861872 PMCID: PMC3179954 DOI: 10.1186/1471-2180-11-189] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Accepted: 08/23/2011] [Indexed: 12/05/2022] Open
Abstract
Background Bacterial DNA replication restart pathways facilitate reinitiation of DNA replication following disruptive encounters of a replisome with DNA damage, thereby allowing complete and faithful duplication of the genome. In Neisseria gonorrhoeae, the primosome proteins that catalyze DNA replication restart differ from the well-studied primosome proteins of E. coli with respect to the number of proteins involved and the affinities of their physical interactions: the PriA:PriB interaction is weak in E. coli, but strong in N. gonorrhoeae, and the PriB:DNA interaction is strong in E. coli, but weak in N. gonorrhoeae. In this study, we investigated the functional consequences of this affinity reversal. Results We report that N. gonorrhoeae PriA's DNA binding and unwinding activities are similar to those of E. coli PriA, and N. gonorrhoeae PriA's helicase activity is stimulated by its cognate PriB, as it is in E. coli. This finding is significant because N. gonorrhoeae PriB's single-stranded DNA binding activity is weak relative to that of E. coli PriB, and in E. coli, PriB's single-stranded DNA binding activity is important for PriB stimulation of PriA helicase. Furthermore, a N. gonorrhoeae PriB variant defective for binding single-stranded DNA can stimulate PriA's helicase activity, suggesting that DNA binding by PriB might not be important for PriB stimulation of PriA helicase in N. gonorrhoeae. We also demonstrate that N. gonorrhoeae PriB stimulates ATP hydrolysis catalyzed by its cognate PriA. This activity of PriB has not been observed in E. coli, and could be important for PriB stimulation of PriA helicase in N. gonorrhoeae. Conclusions The results of this study demonstrate that a bacterial PriB homolog with weak single-stranded DNA binding activity can stimulate the DNA unwinding activity of its cognate PriA helicase. While it remains unclear if N. gonorrhoeae PriB's weak DNA binding activity is required for PriB stimulation of PriA helicase, the ability of PriB to stimulate PriA-catalyzed ATP hydrolysis could play an important role. Thus, the weak interaction between N. gonorrhoeae PriB and DNA might be compensated for by the strong interaction between PriB and PriA, which could result in allosteric activation of PriA's ATPase activity.
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Affiliation(s)
- Cui Feng
- Department of Chemistry, University of Dayton, 300 College Park, Dayton, OH 45469, USA
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Masai H, Tanaka T, Kohda D. Stalled replication forks: Making ends meet for recognition and stabilization. Bioessays 2010; 32:687-97. [DOI: 10.1002/bies.200900196] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Gabbai CB, Marians KJ. Recruitment to stalled replication forks of the PriA DNA helicase and replisome-loading activities is essential for survival. DNA Repair (Amst) 2010; 9:202-9. [PMID: 20097140 DOI: 10.1016/j.dnarep.2009.12.009] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
PriA, a 3'-->5' superfamily 2 DNA helicase, acts to remodel stalled replication forks and as a specificity factor for origin-independent assembly of a new replisome at the stalled fork. The ability of PriA to initiate replication at stalled forked structures ensures complete genome replication and helps to protect the cell from illegitimate recombination events. This review focuses on the activities of PriA and its role in replication fork assembly and maintaining genomic integrity.
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Affiliation(s)
- Carolina B Gabbai
- Molecular Biology Program, Weill-Cornell Graduate School of Medical Sciences, New York, NY, USA.
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Szymanski MR, Jezewska MJ, Bujalowski W. The Escherichia coli PriA helicase specifically recognizes gapped DNA substrates: effect of the two nucleotide-binding sites of the enzyme on the recognition process. J Biol Chem 2010; 285:9683-9696. [PMID: 20089865 DOI: 10.1074/jbc.m109.094789] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Energetics and specificity of interactions between the Escherichia coli PriA helicase and the gapped DNAs have been studied, using the quantitative fluorescence titration and analytical ultracentrifugation methods. The gap complex has a surprisingly low minimum total site size, corresponding to approximately 7 nucleotides of the single-stranded DNA (ssDNA), as compared with the site size of approximately 20 nucleotides of the enzyme-ssDNA complex. The dramatic difference in stoichiometries indicates that the enzyme predominantly engages the strong DNA-binding subsite in interactions with the gap and assumes a very different orientation in the gap complex, as compared with the complex with the ssDNA. The helicase binds the ssDNA gaps with 4-5 nucleotides with the highest affinity, which is approximately 3 and approximately 2 orders of magnitude larger than the affinities for the ssDNA and double-stranded DNA, respectively. In the gap complex, the protein does not engage in cooperative interactions with the enzyme predominantly associated with the surrounding dsDNA. Binding of nucleoside triphosphate to the strong and weak nucleotide-binding sites of the helicase eliminates the selectivity of the enzyme for the size of the gap, whereas saturation of both sites with ADP leads to amplified affinity for the ssDNA gap containing 5 nucleotides and engagement of an additional protein area in interactions with the nucleic acid.
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Affiliation(s)
- Michal R Szymanski
- Department of Biochemistry and Molecular Biology, Department of Obstetrics and Gynecology, the Sealy Center for Structural Biology and the Sealy Center for Cancer Cell Biology, The University of Texas Medical Branch, Galveston, Texas 77555-1053
| | - Maria J Jezewska
- Department of Biochemistry and Molecular Biology, Department of Obstetrics and Gynecology, the Sealy Center for Structural Biology and the Sealy Center for Cancer Cell Biology, The University of Texas Medical Branch, Galveston, Texas 77555-1053
| | - Wlodzimierz Bujalowski
- Department of Biochemistry and Molecular Biology, Department of Obstetrics and Gynecology, the Sealy Center for Structural Biology and the Sealy Center for Cancer Cell Biology, The University of Texas Medical Branch, Galveston, Texas 77555-1053.
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