1
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Pelliciari S, Bodet-Lefèvre S, Fenyk S, Stevens D, Winterhalter C, Schramm FD, Pintar S, Burnham DR, Merces G, Richardson TT, Tashiro Y, Hubbard J, Yardimci H, Ilangovan A, Murray H. The bacterial replication origin BUS promotes nucleobase capture. Nat Commun 2023; 14:8339. [PMID: 38097584 PMCID: PMC10721633 DOI: 10.1038/s41467-023-43823-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 11/21/2023] [Indexed: 12/17/2023] Open
Abstract
Genome duplication is essential for the proliferation of cellular life and this process is generally initiated by dedicated replication proteins at chromosome origins. In bacteria, DNA replication is initiated by the ubiquitous DnaA protein, which assembles into an oligomeric complex at the chromosome origin (oriC) that engages both double-stranded DNA (dsDNA) and single-stranded DNA (ssDNA) to promote DNA duplex opening. However, the mechanism of DnaA specifically opening a replication origin was unknown. Here we show that Bacillus subtilis DnaAATP assembles into a continuous oligomer at the site of DNA melting, extending from a dsDNA anchor to engage a single DNA strand. Within this complex, two nucleobases of each ssDNA binding motif (DnaA-trio) are captured within a dinucleotide binding pocket created by adjacent DnaA proteins. These results provide a molecular basis for DnaA specifically engaging the conserved sequence elements within the bacterial chromosome origin basal unwinding system (BUS).
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Affiliation(s)
- Simone Pelliciari
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne, NE2 4AX, UK
| | - Salomé Bodet-Lefèvre
- Centre for Molecular Cell Biology, School of Biological and Behavioural Sciences, Queen Mary University of London, Newark Street, London, E1 2AT, UK
| | - Stepan Fenyk
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne, NE2 4AX, UK
| | - Daniel Stevens
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne, NE2 4AX, UK
| | - Charles Winterhalter
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne, NE2 4AX, UK
| | - Frederic D Schramm
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne, NE2 4AX, UK
| | - Sara Pintar
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne, NE2 4AX, UK
| | - Daniel R Burnham
- The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - George Merces
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne, NE2 4AX, UK
| | - Tomas T Richardson
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne, NE2 4AX, UK
| | - Yumiko Tashiro
- Centre for Molecular Cell Biology, School of Biological and Behavioural Sciences, Queen Mary University of London, Newark Street, London, E1 2AT, UK
| | - Julia Hubbard
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne, NE2 4AX, UK
| | - Hasan Yardimci
- The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Aravindan Ilangovan
- Centre for Molecular Cell Biology, School of Biological and Behavioural Sciences, Queen Mary University of London, Newark Street, London, E1 2AT, UK.
| | - Heath Murray
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne, NE2 4AX, UK.
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2
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Kasho K, Ozaki S, Katayama T. IHF and Fis as Escherichia coli Cell Cycle Regulators: Activation of the Replication Origin oriC and the Regulatory Cycle of the DnaA Initiator. Int J Mol Sci 2023; 24:11572. [PMID: 37511331 PMCID: PMC10380432 DOI: 10.3390/ijms241411572] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 07/14/2023] [Accepted: 07/16/2023] [Indexed: 07/30/2023] Open
Abstract
This review summarizes current knowledge about the mechanisms of timely binding and dissociation of two nucleoid proteins, IHF and Fis, which play fundamental roles in the initiation of chromosomal DNA replication in Escherichia coli. Replication is initiated from a unique replication origin called oriC and is tightly regulated so that it occurs only once per cell cycle. The timing of replication initiation at oriC is rigidly controlled by the timely binding of the initiator protein DnaA and IHF to oriC. The first part of this review presents up-to-date knowledge about the timely stabilization of oriC-IHF binding at oriC during replication initiation. Recent advances in our understanding of the genome-wide profile of cell cycle-coordinated IHF binding have revealed the oriC-specific stabilization of IHF binding by ATP-DnaA oligomers at oriC and by an initiation-specific IHF binding consensus sequence at oriC. The second part of this review summarizes the mechanism of the timely regulation of DnaA activity via the chromosomal loci DARS2 (DnaA-reactivating sequence 2) and datA. The timing of replication initiation at oriC is controlled predominantly by the phosphorylated form of the adenosine nucleotide bound to DnaA, i.e., ATP-DnaA, but not ADP-ADP, is competent for initiation. Before initiation, DARS2 increases the level of ATP-DnaA by stimulating the exchange of ADP for ATP on DnaA. This DARS2 function is activated by the site-specific and timely binding of both IHF and Fis within DARS2. After initiation, another chromosomal locus, datA, which inactivates ATP-DnaA by stimulating ATP hydrolysis, is activated by the timely binding of IHF. A recent study has shown that ATP-DnaA oligomers formed at DARS2-Fis binding sites competitively dissociate Fis via negative feedback, whereas IHF regulation at DARS2 and datA still remains to be investigated. This review summarizes the current knowledge about the specific role of IHF and Fis in the regulation of replication initiation and proposes a mechanism for the regulation of timely IHF binding and dissociation at DARS2 and datA.
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Affiliation(s)
- Kazutoshi Kasho
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Shogo Ozaki
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
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3
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Yoshida R, Ozaki S, Kawakami H, Katayama T. Single-stranded DNA recruitment mechanism in replication origin unwinding by DnaA initiator protein and HU, an evolutionary ubiquitous nucleoid protein. Nucleic Acids Res 2023; 51:6286-6306. [PMID: 37178000 PMCID: PMC10325909 DOI: 10.1093/nar/gkad389] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 04/18/2023] [Accepted: 05/02/2023] [Indexed: 05/15/2023] Open
Abstract
The Escherichia coli replication origin oriC contains the initiator ATP-DnaA-Oligomerization Region (DOR) and its flanking duplex unwinding element (DUE). In the Left-DOR subregion, ATP-DnaA forms a pentamer by binding to R1, R5M and three other DnaA boxes. The DNA-bending protein IHF binds sequence-specifically to the interspace between R1 and R5M boxes, promoting DUE unwinding, which is sustained predominantly by binding of R1/R5M-bound DnaAs to the single-stranded DUE (ssDUE). The present study describes DUE unwinding mechanisms promoted by DnaA and IHF-structural homolog HU, a ubiquitous protein in eubacterial species that binds DNA sequence-non-specifically, preferring bent DNA. Similar to IHF, HU promoted DUE unwinding dependent on ssDUE binding of R1/R5M-bound DnaAs. Unlike IHF, HU strictly required R1/R5M-bound DnaAs and interactions between the two DnaAs. Notably, HU site-specifically bound the R1-R5M interspace in a manner stimulated by ATP-DnaA and ssDUE. These findings suggest a model that interactions between the two DnaAs trigger DNA bending within the R1/R5M-interspace and initial DUE unwinding, which promotes site-specific HU binding that stabilizes the overall complex and DUE unwinding. Moreover, HU site-specifically bound the replication origin of the ancestral bacterium Thermotoga maritima depending on the cognate ATP-DnaA. The ssDUE recruitment mechanism could be evolutionarily conserved in eubacteria.
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Affiliation(s)
- Ryusei Yoshida
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Shogo Ozaki
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Hironori Kawakami
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
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4
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Lu C, Yoshida R, Katayama T, Ozaki S. Thermotoga maritima oriC involves a DNA unwinding element with distinct modules and a DnaA-oligomerizing region with a novel directional binding mode. J Biol Chem 2023:104888. [PMID: 37276959 PMCID: PMC10316083 DOI: 10.1016/j.jbc.2023.104888] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 05/23/2023] [Accepted: 05/30/2023] [Indexed: 06/07/2023] Open
Abstract
Initiation of chromosomal replication requires dynamic nucleoprotein complexes. In most eubacteria, the origin oriC contains multiple DnaA box sequences to which the ubiquitous DnaA initiators bind. In Escherichia coli oriC, DnaA boxes sustain construction of higher-order complexes via DnaA-DnaA interactions, promoting the unwinding of the DNA unwinding element (DUE) within oriC and concomitantly binding the single-stranded DUE to install replication machinery. Despite the significant sequence homologies among DnaA proteins, bacterial oriC sequences are highly diverse. The present study investigated the design of oriC (tma-oriC) from Thermotoga maritima, an evolutionarily ancient eubacterium. The minimal tma-oriC sequence includes a DUE and a flanking region containing five DnaA boxes recognized by the cognate DnaA initiator (tmaDnaA). This DUE was comprised of two distinct functional modules, an unwinding module and a tmaDnaA-binding module. Three direct repeats of the trinucleotide TAG within DUE were essential for both unwinding and single-stranded DUE binding by tmaDnaA complexes constructed on the DnaA boxes. Its surrounding AT-rich sequences stimulated only duplex unwinding. Moreover, head-to-tail oligomers of ATP-bound tmaDnaA were constructed within tma-oriC, irrespective of the directions of the DnaA boxes. This binding mode was considered to be induced by flexible swiveling of DnaA domains III and IV, which were responsible for DnaA-DnaA interactions and DnaA box binding, respectively. Phasing of specific tmaDnaA boxes in tma-oriC DNA was also responsible for unwinding. These findings indicate that a single-stranded DUE recruitment mechanism was responsible for unwinding, and would enhance understanding of the fundamental molecular nature of the origin sequences present in evolutionarily divergent bacteria.
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Affiliation(s)
- Chuyuan Lu
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan
| | - Ryusei Yoshida
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan
| | - Shogo Ozaki
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan.
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5
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Sakiyama Y, Nagata M, Yoshida R, Kasho K, Ozaki S, Katayama T. Concerted actions of DnaA complexes with DNA-unwinding sequences within and flanking replication origin oriC promote DnaB helicase loading. J Biol Chem 2022; 298:102051. [PMID: 35598828 PMCID: PMC9198467 DOI: 10.1016/j.jbc.2022.102051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 05/11/2022] [Accepted: 05/13/2022] [Indexed: 12/01/2022] Open
Abstract
Unwinding of the replication origin and loading of DNA helicases underlie the initiation of chromosomal replication. In Escherichia coli, the minimal origin oriC contains a duplex unwinding element (DUE) region and three (Left, Middle, and Right) regions that bind the initiator protein DnaA. The Left/Right regions bear a set of DnaA-binding sequences, constituting the Left/Right-DnaA subcomplexes, while the Middle region has a single DnaA-binding site, which stimulates formation of the Left/Right-DnaA subcomplexes. In addition, a DUE-flanking AT-cluster element (TATTAAAAAGAA) is located just outside of the minimal oriC region. The Left-DnaA subcomplex promotes unwinding of the flanking DUE exposing TT[A/G]T(T) sequences that then bind to the Left-DnaA subcomplex, stabilizing the unwound state required for DnaB helicase loading. However, the role of the Right-DnaA subcomplex is largely unclear. Here, we show that DUE unwinding by both the Left/Right-DnaA subcomplexes, but not the Left-DnaA subcomplex only, was stimulated by a DUE-terminal subregion flanking the AT-cluster. Consistently, we found the Right-DnaA subcomplex–bound single-stranded DUE and AT-cluster regions. In addition, the Left/Right-DnaA subcomplexes bound DnaB helicase independently. For only the Left-DnaA subcomplex, we show the AT-cluster was crucial for DnaB loading. The role of unwound DNA binding of the Right-DnaA subcomplex was further supported by in vivo data. Taken together, we propose a model in which the Right-DnaA subcomplex dynamically interacts with the unwound DUE, assisting in DUE unwinding and efficient loading of DnaB helicases, while in the absence of the Right-DnaA subcomplex, the AT-cluster assists in those processes, supporting robustness of replication initiation.
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Affiliation(s)
- Yukari Sakiyama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Mariko Nagata
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Ryusei Yoshida
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Kazutoshi Kasho
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Shogo Ozaki
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.
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6
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Miyoshi K, Tatsumoto Y, Ozaki S, Katayama T. Negative feedback for DARS2-Fis complex by ATP-DnaA supports the cell cycle-coordinated regulation for chromosome replication. Nucleic Acids Res 2021; 49:12820-12835. [PMID: 34871419 PMCID: PMC8682772 DOI: 10.1093/nar/gkab1171] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 11/05/2021] [Accepted: 11/11/2021] [Indexed: 11/13/2022] Open
Abstract
In Escherichia coli, the replication initiator DnaA oscillates between an ATP- and an ADP-bound state in a cell cycle-dependent manner, supporting regulation for chromosome replication. ATP-DnaA cooperatively assembles on the replication origin using clusters of low-affinity DnaA-binding sites. After initiation, DnaA-bound ATP is hydrolyzed, producing initiation-inactive ADP-DnaA. For the next round of initiation, ADP-DnaA binds to the chromosomal locus DARS2, which promotes the release of ADP, yielding the apo-DnaA to regain the initiation activity through ATP binding. This DnaA reactivation by DARS2 depends on site-specific binding of IHF (integration host factor) and Fis proteins and IHF binding to DARS2 occurs specifically during pre-initiation. Here, we reveal that Fis binds to an essential region in DARS2 specifically during pre-initiation. Further analyses demonstrate that ATP-DnaA, but not ADP-DnaA, oligomerizes on a cluster of low-affinity DnaA-binding sites overlapping the Fis-binding region, which competitively inhibits Fis binding and hence the DARS2 activity. DiaA (DnaA initiator-associating protein) stimulating ATP-DnaA assembly enhances the dissociation of Fis. These observations lead to a negative feedback model where the activity of DARS2 is repressed around the time of initiation by the elevated ATP-DnaA level and is stimulated following initiation when the ATP-DnaA level is reduced.
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Affiliation(s)
- Kenya Miyoshi
- Department of Molecular Biology, Kyushu University Graduate School of Pharmaceutical Sciences, Fukuoka 812-8582, Japan
| | - Yuka Tatsumoto
- Department of Molecular Biology, Kyushu University Graduate School of Pharmaceutical Sciences, Fukuoka 812-8582, Japan
| | - Shogo Ozaki
- Department of Molecular Biology, Kyushu University Graduate School of Pharmaceutical Sciences, Fukuoka 812-8582, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Kyushu University Graduate School of Pharmaceutical Sciences, Fukuoka 812-8582, Japan
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7
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Grimwade JE, Leonard AC. Blocking, Bending, and Binding: Regulation of Initiation of Chromosome Replication During the Escherichia coli Cell Cycle by Transcriptional Modulators That Interact With Origin DNA. Front Microbiol 2021; 12:732270. [PMID: 34616385 PMCID: PMC8488378 DOI: 10.3389/fmicb.2021.732270] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 08/18/2021] [Indexed: 11/25/2022] Open
Abstract
Genome duplication is a critical event in the reproduction cycle of every cell. Because all daughter cells must inherit a complete genome, chromosome replication is tightly regulated, with multiple mechanisms focused on controlling when chromosome replication begins during the cell cycle. In bacteria, chromosome duplication starts when nucleoprotein complexes, termed orisomes, unwind replication origin (oriC) DNA and recruit proteins needed to build new replication forks. Functional orisomes comprise the conserved initiator protein, DnaA, bound to a set of high and low affinity recognition sites in oriC. Orisomes must be assembled each cell cycle. In Escherichia coli, the organism in which orisome assembly has been most thoroughly examined, the process starts with DnaA binding to high affinity sites after chromosome duplication is initiated, and orisome assembly is completed immediately before the next initiation event, when DnaA interacts with oriC’s lower affinity sites, coincident with origin unwinding. A host of regulators, including several transcriptional modulators, targets low affinity DnaA-oriC interactions, exerting their effects by DNA bending, blocking access to recognition sites, and/or facilitating binding of DnaA to both DNA and itself. In this review, we focus on orisome assembly in E. coli. We identify three known transcriptional modulators, SeqA, Fis (factor for inversion stimulation), and IHF (integration host factor), that are not essential for initiation, but which interact directly with E. coli oriC to regulate orisome assembly and replication initiation timing. These regulators function by blocking sites (SeqA) and bending oriC DNA (Fis and IHF) to inhibit or facilitate cooperative low affinity DnaA binding. We also examine how the growth rate regulation of Fis levels might modulate IHF and DnaA binding to oriC under a variety of nutritional conditions. Combined, the regulatory mechanisms mediated by transcriptional modulators help ensure that at all growth rates, bacterial chromosome replication begins once, and only once, per cell cycle.
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Affiliation(s)
- Julia E Grimwade
- Microbial Genetics Laboratory, Biological Sciences Program, Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL, United States
| | - Alan C Leonard
- Microbial Genetics Laboratory, Biological Sciences Program, Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL, United States
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8
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Kasho K, Oshima T, Chumsakul O, Nakamura K, Fukamachi K, Katayama T. Whole-Genome Analysis Reveals That the Nucleoid Protein IHF Predominantly Binds to the Replication Origin oriC Specifically at the Time of Initiation. Front Microbiol 2021; 12:697712. [PMID: 34475859 PMCID: PMC8407004 DOI: 10.3389/fmicb.2021.697712] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 07/26/2021] [Indexed: 11/20/2022] Open
Abstract
The structure and function of bacterial chromosomes are dynamically regulated by a wide variety of nucleoid-associated proteins (NAPs) and DNA superstructures, such as DNA supercoiling. In Escherichia coli, integration host factor (IHF), a NAP, binds to specific transcription promoters and regulatory DNA elements of DNA replication such as the replication origin oriC: binding to these elements depends on the cell cycle but underlying mechanisms are unknown. In this study, we combined GeF-seq (genome footprinting with high-throughput sequencing) with synchronization of the E. coli cell cycle to determine the genome-wide, cell cycle-dependent binding of IHF with base-pair resolution. The GeF-seq results in this study were qualified enough to analyze genomic IHF binding sites (e.g., oriC and the transcriptional promoters of ilvG and osmY) except some of the known sites. Unexpectedly, we found that before replication initiation, oriC was a predominant site for stable IHF binding, whereas all other loci exhibited reduced IHF binding. To reveal the specific mechanism of stable oriC–IHF binding, we inserted a truncated oriC sequence in the terC (replication terminus) locus of the genome. Before replication initiation, stable IHF binding was detected even at this additional oriC site, dependent on the specific DnaA-binding sequence DnaA box R1 within the site. DnaA oligomers formed on oriC might protect the oriC–IHF complex from IHF dissociation. After replication initiation, IHF rapidly dissociated from oriC, and IHF binding to other sites was sustained or stimulated. In addition, we identified a novel locus associated with cell cycle-dependent IHF binding. These findings provide mechanistic insight into IHF binding and dissociation in the genome.
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Affiliation(s)
- Kazutoshi Kasho
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Taku Oshima
- Department of Biotechnology, Toyama Prefectural University, Toyama, Japan
| | - Onuma Chumsakul
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Nara, Japan
| | - Kensuke Nakamura
- Department of Life Science and Informatics, Maebashi Institute of Technology, Maebashi, Japan
| | - Kazuki Fukamachi
- Department of Biotechnology, Toyama Prefectural University, Toyama, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
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9
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Chatterjee S, Jha JK, Ciaccia P, Venkova T, Chattoraj DK. Interactions of replication initiator RctB with single- and double-stranded DNA in origin opening of Vibrio cholerae chromosome 2. Nucleic Acids Res 2020; 48:11016-11029. [PMID: 33035310 DOI: 10.1093/nar/gkaa826] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 09/14/2020] [Accepted: 09/17/2020] [Indexed: 12/16/2022] Open
Abstract
Studies of bacterial chromosomes and plasmids indicate that their replication initiator proteins bind to origins of replication at many double-stranded sites and also at AT-rich regions where single-stranded DNA is exposed during origin opening. Single-strand binding apparently promotes origin opening by stabilizing an open structure, but how the initiator participates in this process and the contributions of the several binding sites remain unclear. Here, we show that the initiator protein of Vibrio cholerae specific to chromosome 2 (Chr2) also has single-strand binding activity in the AT-rich region of its origin. Binding is strand specific, depends on repeats of the sequence 5'ATCA and is greatly stabilized in vitro by specific double-stranded sites of the origin. The stability derives from the formation of ternary complexes of the initiator with the single- and double-stranded sites. An IHF site lies between these two kinds of sites in the Chr2 origin and an IHF-induced looping out of the intervening DNA mediates their interaction. Simultaneous binding to two kinds of sites in the origin appears to be a common mechanism by which bacterial replication initiators stabilize an open origin.
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Affiliation(s)
- Soniya Chatterjee
- Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892-4260, USA
| | - Jyoti K Jha
- Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892-4260, USA
| | - Peter Ciaccia
- Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892-4260, USA
| | - Tatiana Venkova
- Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892-4260, USA
| | - Dhruba K Chattoraj
- Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892-4260, USA
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10
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Oliveira Paiva AM, van Eijk E, Friggen AH, Weigel C, Smits WK. Identification of the Unwinding Region in the Clostridioides difficile Chromosomal Origin of Replication. Front Microbiol 2020; 11:581401. [PMID: 33133049 PMCID: PMC7561715 DOI: 10.3389/fmicb.2020.581401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 08/31/2020] [Indexed: 12/14/2022] Open
Abstract
Faithful DNA replication is crucial for viability of cells across all kingdoms. Targeting DNA replication is a viable strategy for inhibition of bacterial pathogens. Clostridioides difficile is an important enteropathogen that causes potentially fatal intestinal inflammation. Knowledge about DNA replication in this organism is limited and no data is available on the very first steps of DNA replication. Here, we use a combination of in silico predictions and in vitro experiments to demonstrate that C. difficile employs a bipartite origin of replication that shows DnaA-dependent melting at oriC2, located in the dnaA-dnaN intergenic region. Analysis of putative origins of replication in different clostridia suggests that the main features of the origin architecture are conserved. This study is the first to characterize aspects of the origin region of C. difficile and contributes to our understanding of the initiation of DNA replication in clostridia.
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Affiliation(s)
- Ana M Oliveira Paiva
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, Netherlands.,Centre for Microbial Cell Biology, Leiden, Netherlands
| | - Erika van Eijk
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, Netherlands
| | - Annemieke H Friggen
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, Netherlands
| | - Christoph Weigel
- Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany
| | - Wiep Klaas Smits
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, Netherlands.,Centre for Microbial Cell Biology, Leiden, Netherlands
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11
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Hayashi C, Miyazaki E, Ozaki S, Abe Y, Katayama T. DnaB helicase is recruited to the replication initiation complex via binding of DnaA domain I to the lateral surface of the DnaB N-terminal domain. J Biol Chem 2020; 295:11131-11143. [PMID: 32540966 DOI: 10.1074/jbc.ra120.014235] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 06/10/2020] [Indexed: 01/09/2023] Open
Abstract
The DNA replication protein DnaA in Escherichia coli constructs higher-order complexes on the origin, oriC, to unwind this region. DnaB helicase is loaded onto unwound oriC via interactions with the DnaC loader and the DnaA complex. The DnaB-DnaC complex is recruited to the DnaA complex via stable binding of DnaB to DnaA domain I. The DnaB-DnaC complex is then directed to unwound oriC via a weak interaction between DnaB and DnaA domain III. Previously, we showed that Phe46 in DnaA domain I binds to DnaB. Here, we searched for the DnaA domain I-binding site in DnaB. The DnaB L160A variant was impaired in binding to DnaA complex on oriC but retained its DnaC-binding and helicase activities. DnaC binding moderately stimulated DnaA binding of DnaB L160A, and loading of DnaB L160A onto oriC was consistently and moderately inhibited. In a helicase assay with partly single-stranded DNA bearing a DnaA-binding site, DnaA stimulated DnaB loading, which was strongly inhibited in DnaB L160A even in the presence of DnaC. DnaB L160A was functionally impaired in vivo On the basis of these findings, we propose that DnaB Leu160 interacts with DnaA domain I Phe46 DnaB Leu160 is exposed on the lateral surface of the N-terminal domain, which can explain unobstructed interactions of DnaA domain I-bound DnaB with DnaC, DnaG primase, and DnaA domain III. We propose a probable structure for the DnaA-DnaB-DnaC complex, which could be relevant to the process of DnaB loading onto oriC.
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Affiliation(s)
- Chihiro Hayashi
- Department of Molecular Biology, Kyushu University Graduate School of Pharmaceutical Sciences, Fukuoka, Japan
| | - Erika Miyazaki
- Department of Molecular Biology, Kyushu University Graduate School of Pharmaceutical Sciences, Fukuoka, Japan
| | - Shogo Ozaki
- Department of Molecular Biology, Kyushu University Graduate School of Pharmaceutical Sciences, Fukuoka, Japan
| | - Yoshito Abe
- Department of Protein Structure, Function, and Design, Kyushu University Graduate School of Pharmaceutical Sciences, Fukuoka, Japan.,Department of Pharmaceutical Sciences, International University of Health and Welfare, Okawa, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Kyushu University Graduate School of Pharmaceutical Sciences, Fukuoka, Japan
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12
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Sugiyama R, Kasho K, Miyoshi K, Ozaki S, Kagawa W, Kurumizaka H, Katayama T. A novel mode of DnaA-DnaA interaction promotes ADP dissociation for reactivation of replication initiation activity. Nucleic Acids Res 2020; 47:11209-11224. [PMID: 31535134 PMCID: PMC6868365 DOI: 10.1093/nar/gkz795] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 09/03/2019] [Accepted: 09/07/2019] [Indexed: 01/01/2023] Open
Abstract
ATP-DnaA is temporally increased to initiate replication during the cell cycle. Two chromosomal loci, DARS (DnaA-reactivating sequences) 1 and 2, promote ATP-DnaA production by nucleotide exchange of ADP-DnaA for timely initiation. ADP-DnaA complexes are constructed on DARS1 and DARS2, bearing a cluster of three DnaA-binding sequences (DnaA boxes I−III), promoting ADP dissociation. Although DnaA has an AAA+ domain, which ordinarily directs construction of oligomers in a head-to-tail manner, DnaA boxes I and II are oriented oppositely. In this study, we constructed a structural model of a head-to-head dimer of DnaA AAA+ domains, and analyzed residues residing on the interface of the model dimer. Gln208 was specifically required for DARS-dependent ADP dissociation in vitro, and in vivo analysis yielded consistent results. Additionally, ADP release from DnaA protomers bound to DnaA boxes I and II was dependent on Gln208 of the DnaA protomers, and DnaA box III-bound DnaA did not release ADP nor require Gln208 for ADP dissociation by DARS–DnaA complexes. Based on these and other findings, we propose a model for DARS–DnaA complex dynamics during ADP dissociation, and provide novel insight into the regulatory mechanisms of DnaA and the interaction modes of AAA+ domains.
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Affiliation(s)
- Ryo Sugiyama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan
| | - Kazutoshi Kasho
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan
| | - Kenya Miyoshi
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan
| | - Shogo Ozaki
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan
| | - Wataru Kagawa
- Department of Chemistry, Graduate School of Science and Engineering, Meisei University, Hino, Tokyo 191-8506, Japan
| | - Hitoshi Kurumizaka
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan
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13
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Płachetka M, Żyła-Uklejewicz D, Weigel C, Donczew R, Donczew M, Jakimowicz D, Zawilak-Pawlik A, Zakrzewska-Czerwinska J. Streptomycete origin of chromosomal replication with two putative unwinding elements. MICROBIOLOGY-SGM 2019; 165:1365-1375. [PMID: 31592764 DOI: 10.1099/mic.0.000859] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
DNA replication is controlled mostly at the initiation step. In bacteria, replication of the chromosome starts at a single origin of replication called oriC. The initiator protein, DnaA, binds to specific sequences (DnaA boxes) within oriC and assembles into a filament that promotes DNA double helix opening within the DNA unwinding element (DUE). This process has been thoroughly examined in model bacteria, including Escherichia coli and Bacillus subtilis, but we have a relatively limited understanding of chromosomal replication initiation in other species. Here, we reveal new details of DNA replication initiation in Streptomyces, a group of Gram-positive soil bacteria that possesses a long linear (8-10 Mbps) and GC-rich chromosome with a centrally positioned oriC. We used comprehensive in silico, in vitro and in vivo analyses to better characterize the structure of Streptomyces oriC. We identified 14 DnaA-binding motifs and determined the consensus sequence of the DnaA box. Unexpectedly, our in silico analysis using the WebSIDD algorithm revealed the presence of two putative Streptomyces DUEs (DUE1 and DUE2) located very near one another toward the 5' end of the oriC region. In vitro P1 nuclease assay revealed that DNA unwinding occurs at both of the proposed sites, but using an in vivo replication initiation point mapping, we were able to confirm only one of them (DUE2). The previously observed transcriptional activity of the Streptomyces oriC region may help explain the current results. We speculate that transcription itself could modulate oriC activity in Streptomyces by determining whether DNA unwinding occurs at DUE1 or DUE2.
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Affiliation(s)
- Małgorzata Płachetka
- Department of Molecular Microbiology, Faculty of Biotechnology, University of Wroclaw, Wroclaw, Poland
| | - Dorota Żyła-Uklejewicz
- Department of Microbiology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland
| | - Christoph Weigel
- Institute of Biotechnology, Faculty III, Technical University Berlin (TUB), Berlin, Germany
| | - Rafał Donczew
- Present address: Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.,Department of Microbiology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland
| | - Magdalena Donczew
- Present address: Center for Infectious Disease, Seattle, WA, USA.,Department of Molecular Microbiology, Faculty of Biotechnology, University of Wroclaw, Wroclaw, Poland
| | - Dagmara Jakimowicz
- Department of Molecular Microbiology, Faculty of Biotechnology, University of Wroclaw, Wroclaw, Poland
| | - Anna Zawilak-Pawlik
- Department of Microbiology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland
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14
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Leonard AC, Rao P, Kadam RP, Grimwade JE. Changing Perspectives on the Role of DnaA-ATP in Orisome Function and Timing Regulation. Front Microbiol 2019; 10:2009. [PMID: 31555240 PMCID: PMC6727663 DOI: 10.3389/fmicb.2019.02009] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Accepted: 08/16/2019] [Indexed: 01/20/2023] Open
Abstract
Bacteria, like all cells, must precisely duplicate their genomes before they divide. Regulation of this critical process focuses on forming a pre-replicative nucleoprotein complex, termed the orisome. Orisomes perform two essential mechanical tasks that configure the unique chromosomal replication origin, oriC to start a new round of chromosome replication: (1) unwinding origin DNA and (2) assisting with loading of the replicative DNA helicase on exposed single strands. In Escherichia coli, a necessary orisome component is the ATP-bound form of the bacterial initiator protein, DnaA. DnaA-ATP differs from DnaA-ADP in its ability to oligomerize into helical filaments, and in its ability to access a subset of low affinity recognition sites in the E. coli replication origin. The helical filaments have been proposed to play a role in both of the key mechanical tasks, but recent studies raise new questions about whether they are mandatory for orisome activity. It was recently shown that a version of E. coli oriC (oriCallADP), whose multiple low affinity DnaA recognition sites bind DnaA-ATP and DnaA-ADP similarly, was fully occupied and unwound by DnaA-ADP in vitro, and in vivo suppressed the lethality of DnaA mutants defective in ATP binding and ATP-specific oligomerization. However, despite their functional equivalency, orisomes assembled on oriCallADP were unable to trigger chromosome replication at the correct cell cycle time and displayed a hyper-initiation phenotype. Here we present a new perspective on DnaA-ATP, and suggest that in E. coli, DnaA-ATP is not required for mechanical functions, but rather is needed for site recognition and occupation, so that initiation timing is coupled to DnaA-ATP levels. We also discuss how other bacterial types may utilize DnaA-ATP and DnaA-ADP, and whether the high diversity of replication origins in the bacterial world reflects different regulatory strategies for how DnaA-ATP is used to control orisome assembly.
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Affiliation(s)
- Alan C Leonard
- Laboratory of Microbial Genetics, Department of Biomedical and Chemical Engineering and Science, Florida Institute of Technology, Melbourne, FL, United States
| | - Prassanna Rao
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Rohit P Kadam
- Laboratory of Microbial Genetics, Department of Biomedical and Chemical Engineering and Science, Florida Institute of Technology, Melbourne, FL, United States
| | - Julia E Grimwade
- Laboratory of Microbial Genetics, Department of Biomedical and Chemical Engineering and Science, Florida Institute of Technology, Melbourne, FL, United States
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15
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Blocking the Trigger: Inhibition of the Initiation of Bacterial Chromosome Replication as an Antimicrobial Strategy. Antibiotics (Basel) 2019; 8:antibiotics8030111. [PMID: 31390740 PMCID: PMC6784150 DOI: 10.3390/antibiotics8030111] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 08/02/2019] [Accepted: 08/04/2019] [Indexed: 12/19/2022] Open
Abstract
All bacterial cells must duplicate their genomes prior to dividing into two identical daughter cells. Chromosome replication is triggered when a nucleoprotein complex, termed the orisome, assembles, unwinds the duplex DNA, and recruits the proteins required to establish new replication forks. Obviously, the initiation of chromosome replication is essential to bacterial reproduction, but this process is not inhibited by any of the currently-used antimicrobial agents. Given the urgent need for new antibiotics to combat drug-resistant bacteria, it is logical to evaluate whether or not unexploited bacterial processes, such as orisome assembly, should be more closely examined for sources of novel drug targets. This review will summarize current knowledge about the proteins required for bacterial chromosome initiation, as well as how orisomes assemble and are regulated. Based upon this information, we discuss current efforts and potential strategies and challenges for inhibiting this initiation pharmacologically.
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16
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Richardson TT, Stevens D, Pelliciari S, Harran O, Sperlea T, Murray H. Identification of a basal system for unwinding a bacterial chromosome origin. EMBO J 2019; 38:e101649. [PMID: 31267560 PMCID: PMC6669920 DOI: 10.15252/embj.2019101649] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 06/06/2019] [Accepted: 06/07/2019] [Indexed: 01/03/2023] Open
Abstract
Genome duplication is essential for cell proliferation, and DNA synthesis is generally initiated by dedicated replication proteins at specific loci termed origins. In bacteria, the master initiator DnaA binds the chromosome origin (oriC) and unwinds the DNA duplex to permit helicase loading. However, despite decades of research it remained unclear how the information encoded within oriC guides DnaA-dependent strand separation. To address this fundamental question, we took a systematic genetic approach in vivo and identified the core set of essential sequence elements within the Bacillus subtilis chromosome origin unwinding region. Using this information, we then show in vitro that the minimal replication origin sequence elements are necessary and sufficient to promote the mechanical functions of DNA duplex unwinding by DnaA. Because the basal DNA unwinding system characterized here appears to be conserved throughout the bacterial domain, this discovery provides a framework for understanding oriC architecture, activity, regulation and diversity.
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Affiliation(s)
- Tomas T Richardson
- Centre for Bacterial Cell BiologyInstitute for Cell and Molecular BiosciencesNewcastle UniversityNewcastle Upon TyneUK
| | - Daniel Stevens
- Centre for Bacterial Cell BiologyInstitute for Cell and Molecular BiosciencesNewcastle UniversityNewcastle Upon TyneUK
| | - Simone Pelliciari
- Centre for Bacterial Cell BiologyInstitute for Cell and Molecular BiosciencesNewcastle UniversityNewcastle Upon TyneUK
| | - Omar Harran
- Centre for Bacterial Cell BiologyInstitute for Cell and Molecular BiosciencesNewcastle UniversityNewcastle Upon TyneUK
| | - Theodor Sperlea
- Chromosome Biology GroupLOEWE Center for Synthetic MicrobiologySYNMIKROPhilipps‐Universität MarburgMarburgGermany
| | - Heath Murray
- Centre for Bacterial Cell BiologyInstitute for Cell and Molecular BiosciencesNewcastle UniversityNewcastle Upon TyneUK
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17
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Li X, Zhang Y, Zhou X, Hu X, Zhou Y, Liu D, Maxwell A, Mi K. The plasmid-borne quinolone resistance protein QnrB, a novel DnaA-binding protein, increases the bacterial mutation rate by triggering DNA replication stress. Mol Microbiol 2019; 111:1529-1543. [PMID: 30838726 PMCID: PMC6617969 DOI: 10.1111/mmi.14235] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/01/2019] [Indexed: 02/02/2023]
Abstract
Bacterial antibiotic resistance, a global health threat, is caused by plasmid transfer or genetic mutations. Quinolones are important antibiotics, partially because they are fully synthetic and resistance genes are unlikely to exist in nature; nonetheless, quinolone resistance proteins have been identified. The mechanism by which plasmid-borne quinolone resistance proteins promotes the selection of quinolone-resistant mutants is unclear. Here, we show that QnrB increases the bacterial mutation rate. Transcriptomic and genome sequencing analyses showed that QnrB promoted gene abundance near the origin of replication (oriC). In addition, the QnrB expression level correlated with the replication origin to terminus (oriC/ter) ratio, indicating QnrB-induced DNA replication stress. Our results also show that QnrB is a DnaA-binding protein that may act as an activator of DNA replication initiation. Interaction of QnrB with DnaA promoted the formation of the DnaA-oriC open complex, which leads to DNA replication over-initiation. Our data indicate that plasmid-borne QnrB increases bacterial mutation rates and that genetic changes can alleviate the fitness cost imposed by transmitted plasmids. Derivative mutations may impair antibiotic efficacy and threaten the value of antibiotic treatments. Enhanced understanding of how bacteria adapt to the antibiotic environment will lead to new therapeutic strategies for antibiotic-resistant infections.
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Affiliation(s)
- Xiaojing Li
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yujiao Zhang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Xintong Zhou
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Xinling Hu
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yixuan Zhou
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Di Liu
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Anthony Maxwell
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Kaixia Mi
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing, 101408, China
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18
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Chase J, Catalano A, Noble AJ, Eng ET, Olinares PD, Molloy K, Pakotiprapha D, Samuels M, Chait B, des Georges A, Jeruzalmi D. Mechanisms of opening and closing of the bacterial replicative helicase. eLife 2018; 7:41140. [PMID: 30582519 PMCID: PMC6391071 DOI: 10.7554/elife.41140] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 12/21/2018] [Indexed: 12/31/2022] Open
Abstract
Assembly of bacterial ring-shaped hexameric replicative helicases on single-stranded (ss) DNA requires specialized loading factors. However, mechanisms implemented by these factors during opening and closing of the helicase, which enable and restrict access to an internal chamber, are not known. Here, we investigate these mechanisms in the Escherichia coli DnaB helicase•bacteriophage λ helicase loader (λP) complex. We show that five copies of λP bind at DnaB subunit interfaces and reconfigure the helicase into an open spiral conformation that is intermediate to previously observed closed ring and closed spiral forms; reconfiguration also produces openings large enough to admit ssDNA into the inner chamber. The helicase is also observed in a restrained inactive configuration that poises it to close on activating signal, and transition to the translocation state. Our findings provide insights into helicase opening, delivery to the origin and ssDNA entry, and closing in preparation for translocation.
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Affiliation(s)
- Jillian Chase
- Department of Chemistry and Biochemistry, City College of New York, New York, United States.,PhD Program in Biochemistry, The Graduate Center of the City University of New York, New York, United States
| | - Andrew Catalano
- Department of Chemistry and Biochemistry, City College of New York, New York, United States
| | - Alex J Noble
- Simons Electron Microscopy Center, The New York Structural Biology Center, New York, United States
| | - Edward T Eng
- Simons Electron Microscopy Center, The New York Structural Biology Center, New York, United States
| | - Paul Db Olinares
- Laboratory for Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, United States
| | - Kelly Molloy
- Laboratory for Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, United States
| | - Danaya Pakotiprapha
- Department of Biochemistry, Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, Thailand.,Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States
| | - Martin Samuels
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States
| | - Brian Chait
- Laboratory for Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, United States
| | - Amedee des Georges
- Department of Chemistry and Biochemistry, City College of New York, New York, United States.,PhD Program in Biochemistry, The Graduate Center of the City University of New York, New York, United States.,Structural Biology Initiative, CUNY Advanced Science Research Center, New York, United States.,PhD Program in Chemistry, The Graduate Center of the City University of New York, New York, United States
| | - David Jeruzalmi
- Department of Chemistry and Biochemistry, City College of New York, New York, United States.,PhD Program in Biochemistry, The Graduate Center of the City University of New York, New York, United States.,PhD Program in Chemistry, The Graduate Center of the City University of New York, New York, United States.,PhD Program in Biology, The Graduate Center of the City University of New York, New York, United States
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19
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Liu J, Zeinert R, Francis L, Chien P. Lon recognition of the replication initiator DnaA requires a bipartite degron. Mol Microbiol 2018; 111:176-186. [PMID: 30288816 DOI: 10.1111/mmi.14146] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/30/2018] [Indexed: 12/17/2022]
Abstract
DnaA initiates chromosome replication in bacteria. In Caulobacter crescentus, the Lon protease degrades DnaA to coordinate replication with nutrient availability and to halt the cell cycle during acute stress. Here, we characterize the mechanism of DnaA recognition by Lon. We find that the folded state of DnaA appears crucial for its degradation, in contrast to the well-known role of Lon in degrading misfolded proteins. We fail to identify a single degradation motif (degron) sufficient for DnaA degradation, rather we show that both the ATPase domain and a species-specific N-terminal motif are important for productive Lon degradation of full-length DnaA. Mutations in either of these determinants disrupt DnaA degradation in vitro and in vivo. However, analysis of truncation products reveals that appending other extensions to the ATPase domain is sufficient to trigger degradation, suggesting plasticity in Lon recognition. Our final working model is that Lon engages DnaA through at least two elements, one of which anchors DnaA to Lon and the other acting as an initiation site for degradation.
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Affiliation(s)
- Jing Liu
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, MA, 01002, USA.,Molecular and Cellular Biology Graduate Program, University of Massachusetts Amherst, MA, 01002, USA
| | - Rilee Zeinert
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, MA, 01002, USA.,Molecular and Cellular Biology Graduate Program, University of Massachusetts Amherst, MA, 01002, USA
| | - Laura Francis
- Department of Biology, University of Massachusetts Amherst, MA, 01002, USA
| | - Peter Chien
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, MA, 01002, USA.,Molecular and Cellular Biology Graduate Program, University of Massachusetts Amherst, MA, 01002, USA
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20
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Sakiyama Y, Nishimura M, Hayashi C, Akama Y, Ozaki S, Katayama T. The DnaA AAA+ Domain His136 Residue Directs DnaB Replicative Helicase to the Unwound Region of the Replication Origin, oriC. Front Microbiol 2018; 9:2017. [PMID: 30233515 PMCID: PMC6127211 DOI: 10.3389/fmicb.2018.02017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 08/09/2018] [Indexed: 11/16/2022] Open
Abstract
Chromosomal replication initiation requires dynamic mechanisms in higher-order nucleoprotein complexes that are constructed at the origin of replication. In Escherichia coli, DnaA molecules construct functional oligomers at the origin oriC, enabling localized unwinding of oriC and stable binding of DnaB helicases via multiple domain I molecules of oriC-bound DnaA. DnaA-bound DnaB helicases are then loaded onto the unwound region of oriC for construction of a pair of replisomes for bidirectional replication. However, mechanisms of DnaB loading to the unwound oriC remain largely elusive. In this study, we determined that His136 of DnaA domain III has an important role in loading of DnaB helicases onto the unwound oriC. DnaA H136A mutant protein was impaired in replication initiation in vivo, and in DnaB loading to the unwound oriC in vitro, whereas the protein fully sustained activities for oriC unwinding and DnaA domain I-dependent stable binding between DnaA and DnaB. Functional and structural analyses supported the idea that transient weak interactions between DnaB helicase and DnaA His136 within specific protomers of DnaA oligomers direct DnaB to a region in close proximity to single stranded DNA at unwound oriC bound to DnaA domain III of the DnaA oligomer. The aromatic moiety of His136 is basically conserved at corresponding residues of eubacterial DnaA orthologs, implying that the guidance function of DnaB is common to all eubacterial species.
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Affiliation(s)
- Yukari Sakiyama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Masahiro Nishimura
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Chihiro Hayashi
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Yusuke Akama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Shogo Ozaki
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
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21
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Rao P, Rozgaja TA, Alqahtani A, Grimwade JE, Leonard AC. Low Affinity DnaA-ATP Recognition Sites in E. coli oriC Make Non-equivalent and Growth Rate-Dependent Contributions to the Regulated Timing of Chromosome Replication. Front Microbiol 2018; 9:1673. [PMID: 30093890 PMCID: PMC6070618 DOI: 10.3389/fmicb.2018.01673] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 07/04/2018] [Indexed: 11/13/2022] Open
Abstract
Although the mechanisms that precisely time initiation of chromosome replication in bacteria remain unclear, most clock models are based on accumulation of the active initiator protein, DnaA-ATP. During each cell division cycle, sufficient DnaA-ATP must become available to interact with a distinct set of low affinity recognition sites in the unique chromosomal replication origin, oriC, and assemble the pre-replicative complex (orisome) that unwinds origin DNA and helps load the replicative helicase. The low affinity oriC-DnaA-ATP interactions are required for the orisome's mechanical functions, and may also play a role in timing of new rounds of DNA synthesis. To further examine this possibility, we constructed chromosomal oriCs with equal preference for DnaA-ADP or DnaA-ATP at one or more low affinity recognition sites, thereby lowering the DnaA-ATP requirement for orisome assembly, and measured the effect of the mutations on cell cycle timing of DNA synthesis. Under slow growth conditions, mutation of any one of the six low affinity DnaA-ATP sites in chromosomal oriC resulted in initiation earlier in the cell cycle, but the shift was not equivalent for every recognition site. Mutation of τ2 caused a greater change in initiation age, suggesting its occupation by DnaA-ATP is a temporal bottleneck during orisome assembly. In contrast, during rapid growth, all origins with a single mutated site displayed wild-type initiation timing. Based on these observations, we propose that E. coli uses two different, DnaA-ATP-dependent initiation timing mechanisms; a slow growth timer that is directly coupled to individual site occupation, and a fast growth timer comprising DnaA-ATP and additional factors that regulate DnaA access to oriC. Analysis of origins with paired mutated sites suggests that Fis is an important component of the fast growth timing mechanism.
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Affiliation(s)
- Prassanna Rao
- Department of Biological Sciences, Florida Institute of Technology, Melbourne, FL, United States
| | | | - Abdulaziz Alqahtani
- Department of Biological Sciences, Florida Institute of Technology, Melbourne, FL, United States
| | - Julia E Grimwade
- Department of Biological Sciences, Florida Institute of Technology, Melbourne, FL, United States
| | - Alan C Leonard
- Department of Biological Sciences, Florida Institute of Technology, Melbourne, FL, United States
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22
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Jaworski P, Donczew R, Mielke T, Weigel C, Stingl K, Zawilak-Pawlik A. Structure and Function of the Campylobacter jejuni Chromosome Replication Origin. Front Microbiol 2018; 9:1533. [PMID: 30050516 PMCID: PMC6052347 DOI: 10.3389/fmicb.2018.01533] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 06/20/2018] [Indexed: 01/23/2023] Open
Abstract
Campylobacter jejuni is the leading bacterial cause of foodborne infections worldwide. However, our understanding of its cell cycle is poor. We identified the probable C. jejuni origin of replication (oriC) - a key element for initiation of chromosome replication, which is also important for chromosome structure, maintenance and dynamics. The herein characterized C. jejuni oriC is monopartite and contains (i) the DnaA box cluster, (ii) the DnaA-dependent DNA unwinding element (DUE) and (iii) binding sites for regulatory proteins. The cluster of five DnaA boxes and the DUE were found in the dnaA-dnaN intergenic region. Binding of DnaA to this cluster of DnaA-boxes enabled unwinding of the DUE in vitro. However, it was not sufficient to sustain replication of minichromosomes, unless the cluster was extended by additional DnaA boxes located in the 3' end of dnaA. This suggests, that C. jejuni oriC requires these boxes to initiate or to regulate replication of its chromosome. However, further detailed mutagenesis is required to confirm the role of these two boxes in initiation of C. jejuni chromosome replication and thus to confirm partial localization of C. jejuni oriC within a coding region, which has not been reported thus far for any bacterial oriC. In vitro DUE unwinding by DnaA was inhibited by Cj1509, an orphan response regulator and a homolog of HP1021, that has been previously shown to inhibit replication in Helicobacter pylori. Thus, Cj1509 might play a similar role as a regulator of C. jejuni chromosome replication. This is the first systematic analysis of chromosome replication initiation in C. jejuni, and we expect that these studies will provide a basis for future research examining the structure and dynamics of the C. jejuni chromosome, which will be crucial for understanding the pathogens' life cycle and virulence.
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Affiliation(s)
- Pawel Jaworski
- Department of Microbiology, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland
| | - Rafal Donczew
- Department of Microbiology, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland
| | - Thorsten Mielke
- Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Christoph Weigel
- Department of Life Science Engineering, Fachbereich 2, HTW Berlin, Berlin, Germany
| | - Kerstin Stingl
- National Reference Laboratory for Campylobacter, Department of Biological Safety, Federal Institute for Risk Assessment, Berlin, Germany
| | - Anna Zawilak-Pawlik
- Department of Microbiology, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland
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23
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Katayama T. Initiation of DNA Replication at the Chromosomal Origin of E. coli, oriC. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1042:79-98. [PMID: 29357054 DOI: 10.1007/978-981-10-6955-0_4] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The Escherichia coli chromosomal origin consists of a duplex-unwinding region and a region bearing a DNA-bending protein, IHF-binding site, and clusters of binding sites for the initiator protein DnaA. ATP-DnaA molecules form highly organized oligomers in a process stimulated by DiaA, a DnaA-binding protein. The resultant ATP-DnaA complexes promote local unwinding of oriC with the aid of IHF, for which specific interaction of DnaA with the single-stranded DNA is crucial. DnaA complexes also interact with DnaB helicases bound to DnaC loaders, promoting loading of DnaB onto the unwound DNA strands for bidirectional replication. Initiation of replication is strictly regulated during the cell cycle by multiple regulatory systems for oriC and DnaA. The activity of oriC is regulated by its methylation state, whereas that of DnaA depends on the form of the bound nucleotide. ATP-DnaA can be yielded from initiation-inactive ADP-DnaA in a timely manner depending on specific chromosomal DNA elements termed DARS (DnaA-reactivating sequences). After initiation, DnaA-bound ATP is hydrolyzed by two systems, yielding ADP-DnaA. In this review, these and other mechanisms of initiation and its regulation in E. coli are described.
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Affiliation(s)
- Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Science, Kyushu University, Fukuoka, Japan.
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24
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Kaguni JM. The Macromolecular Machines that Duplicate the Escherichia coli Chromosome as Targets for Drug Discovery. Antibiotics (Basel) 2018. [PMID: 29538288 PMCID: PMC5872134 DOI: 10.3390/antibiotics7010023] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
DNA replication is an essential process. Although the fundamental strategies to duplicate chromosomes are similar in all free-living organisms, the enzymes of the three domains of life that perform similar functions in DNA replication differ in amino acid sequence and their three-dimensional structures. Moreover, the respective proteins generally utilize different enzymatic mechanisms. Hence, the replication proteins that are highly conserved among bacterial species are attractive targets to develop novel antibiotics as the compounds are unlikely to demonstrate off-target effects. For those proteins that differ among bacteria, compounds that are species-specific may be found. Escherichia coli has been developed as a model system to study DNA replication, serving as a benchmark for comparison. This review summarizes the functions of individual E. coli proteins, and the compounds that inhibit them.
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Affiliation(s)
- Jon M Kaguni
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824-1319, USA.
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25
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Sakiyama Y, Kasho K, Noguchi Y, Kawakami H, Katayama T. Regulatory dynamics in the ternary DnaA complex for initiation of chromosomal replication in Escherichia coli. Nucleic Acids Res 2017; 45:12354-12373. [PMID: 29040689 PMCID: PMC5716108 DOI: 10.1093/nar/gkx914] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 09/29/2017] [Indexed: 12/17/2022] Open
Abstract
In Escherichia coli, the level of the ATP-DnaA initiator is increased temporarily at the time of replication initiation. The replication origin, oriC, contains a duplex-unwinding element (DUE) flanking a DnaA-oligomerization region (DOR), which includes twelve DnaA-binding sites (DnaA boxes) and the DNA-bending protein IHF-binding site (IBS). Although complexes of IHF and ATP-DnaA assembly on the DOR unwind the DUE, the configuration of the crucial nucleoprotein complexes remains elusive. To resolve this, we analyzed individual DnaA protomers in the complex and here demonstrate that the DUE-DnaA-box-R1-IBS-DnaA-box-R5M region is essential for DUE unwinding. R5M-bound ATP-DnaA predominantly promotes ATP-DnaA assembly on the DUE-proximal DOR, and R1-bound DnaA has a supporting role. This mechanism might support timely assembly of ATP-DnaA on oriC. DnaA protomers bound to R1 and R5M directly bind to the unwound DUE strand, which is crucial in replication initiation. Data from in vivo experiments support these results. We propose that the DnaA assembly on the IHF-bent DOR directly binds to the unwound DUE strand, and timely formation of this ternary complex regulates replication initiation. Structural features of oriC support the idea that these mechanisms for DUE unwinding are fundamentally conserved in various bacterial species including pathogens.
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Affiliation(s)
- Yukari Sakiyama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Kazutoshi Kasho
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Yasunori Noguchi
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Hironori Kawakami
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
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26
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Katayama T, Kasho K, Kawakami H. The DnaA Cycle in Escherichia coli: Activation, Function and Inactivation of the Initiator Protein. Front Microbiol 2017; 8:2496. [PMID: 29312202 PMCID: PMC5742627 DOI: 10.3389/fmicb.2017.02496] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 11/30/2017] [Indexed: 01/30/2023] Open
Abstract
This review summarizes the mechanisms of the initiator protein DnaA in replication initiation and its regulation in Escherichia coli. The chromosomal origin (oriC) DNA is unwound by the replication initiation complex to allow loading of DnaB helicases and replisome formation. The initiation complex consists of the DnaA protein, DnaA-initiator-associating protein DiaA, integration host factor (IHF), and oriC, which contains a duplex-unwinding element (DUE) and a DnaA-oligomerization region (DOR) containing DnaA-binding sites (DnaA boxes) and a single IHF-binding site that induces sharp DNA bending. DiaA binds to DnaA and stimulates DnaA assembly at the DOR. DnaA binds tightly to ATP and ADP. ATP-DnaA constructs functionally different sub-complexes at DOR, and the DUE-proximal DnaA sub-complex contains IHF and promotes DUE unwinding. The first part of this review presents the structures and mechanisms of oriC-DnaA complexes involved in the regulation of replication initiation. During the cell cycle, the level of ATP-DnaA level, the active form for initiation, is strictly regulated by multiple systems, resulting in timely replication initiation. After initiation, regulatory inactivation of DnaA (RIDA) intervenes to reduce ATP-DnaA level by hydrolyzing the DnaA-bound ATP to ADP to yield ADP-DnaA, the inactive form. RIDA involves the binding of the DNA polymerase clamp on newly synthesized DNA to the DnaA-inactivator Hda protein. In datA-dependent DnaA-ATP hydrolysis (DDAH), binding of IHF at the chromosomal locus datA, which contains a cluster of DnaA boxes, results in further hydrolysis of DnaA-bound ATP. SeqA protein inhibits untimely initiation at oriC by binding to newly synthesized oriC DNA and represses dnaA transcription in a cell cycle dependent manner. To reinitiate DNA replication, ADP-DnaA forms oligomers at DnaA-reactivating sequences (DARS1 and DARS2), resulting in the dissociation of ADP and the release of nucleotide-free apo-DnaA, which then binds ATP to regenerate ATP-DnaA. In vivo, DARS2 plays an important role in this process and its activation is regulated by timely binding of IHF to DARS2 in the cell cycle. Chromosomal locations of DARS sites are optimized for the strict regulation for timely replication initiation. The last part of this review describes how DDAH and DARS regulate DnaA activity.
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Affiliation(s)
- Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Kazutoshi Kasho
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Hironori Kawakami
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
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27
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Orlova N, Gerding M, Ivashkiv O, Olinares PDB, Chait BT, Waldor MK, Jeruzalmi D. The replication initiator of the cholera pathogen's second chromosome shows structural similarity to plasmid initiators. Nucleic Acids Res 2017; 45:3724-3737. [PMID: 28031373 PMCID: PMC5397143 DOI: 10.1093/nar/gkw1288] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 12/18/2016] [Indexed: 01/23/2023] Open
Abstract
The conserved DnaA-oriC system is used to initiate replication of primary chromosomes throughout the bacterial kingdom; however, bacteria with multipartite genomes evolved distinct systems to initiate replication of secondary chromosomes. In the cholera pathogen, Vibrio cholerae, and in related species, secondary chromosome replication requires the RctB initiator protein. Here, we show that RctB consists of four domains. The structure of its central two domains resembles that of several plasmid replication initiators. RctB contains at least three DNA binding winged-helix-turn-helix motifs, and mutations within any of these severely compromise biological activity. In the structure, RctB adopts a head-to-head dimeric configuration that likely reflects the arrangement in solution. Therefore, major structural reorganization likely accompanies complex formation on the head-to-tail array of binding sites in oriCII. Our findings support the hypothesis that the second Vibrionaceae chromosome arose from an ancestral plasmid, and that RctB may have evolved additional regulatory features.
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Affiliation(s)
- Natalia Orlova
- Department of Chemistry and Biochemistry, City College of New York, New York, NY 10031, USA.,Ph.D. Program in Biochemistry, The Graduate Center of the City University of New York, NY 10016, USA
| | - Matthew Gerding
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, USA.,Division of Infectious Diseases, Brigham and Women's Hospital, Boston, MA, USA.,Howard Hughes Medical Institute, Boston, MA 02115, USA
| | - Olha Ivashkiv
- Department of Chemistry and Biochemistry, City College of New York, New York, NY 10031, USA
| | - Paul Dominic B Olinares
- Laboratory for Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, NY 10021, USA
| | - Brian T Chait
- Laboratory for Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, NY 10021, USA
| | - Matthew K Waldor
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, USA.,Division of Infectious Diseases, Brigham and Women's Hospital, Boston, MA, USA.,Howard Hughes Medical Institute, Boston, MA 02115, USA
| | - David Jeruzalmi
- Department of Chemistry and Biochemistry, City College of New York, New York, NY 10031, USA.,Ph.D. Program in Biochemistry, The Graduate Center of the City University of New York, NY 10016, USA.,Ph.D. Program in Biology, The Graduate Center of the City University of New York, NY 10016, USA.,Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, NY 10016, USA
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28
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Zawilak-Pawlik A, Nowaczyk M, Zakrzewska-Czerwińska J. The Role of the N-Terminal Domains of Bacterial Initiator DnaA in the Assembly and Regulation of the Bacterial Replication Initiation Complex. Genes (Basel) 2017; 8:genes8050136. [PMID: 28489024 PMCID: PMC5448010 DOI: 10.3390/genes8050136] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 04/28/2017] [Accepted: 05/04/2017] [Indexed: 12/22/2022] Open
Abstract
The primary role of the bacterial protein DnaA is to initiate chromosomal replication. The DnaA protein binds to DNA at the origin of chromosomal replication (oriC) and assembles into a filament that unwinds double-stranded DNA. Through interaction with various other proteins, DnaA also controls the frequency and/or timing of chromosomal replication at the initiation step. Escherichia coli DnaA also recruits DnaB helicase, which is present in unwound single-stranded DNA and in turn recruits other protein machinery for replication. Additionally, DnaA regulates the expression of certain genes in E. coli and a few other species. Acting as a multifunctional factor, DnaA is composed of four domains that have distinct, mutually dependent roles. For example, C-terminal domain IV interacts with double-stranded DnaA boxes. Domain III drives ATP-dependent oligomerization, allowing the protein to form a filament that unwinds DNA and subsequently binds to and stabilizes single-stranded DNA in the initial replication bubble; this domain also interacts with multiple proteins that control oligomerization. Domain II constitutes a flexible linker between C-terminal domains III–IV and N-terminal domain I, which mediates intermolecular interactions between DnaA and binds to other proteins that affect DnaA activity and/or formation of the initiation complex. Of these four domains, the role of the N-terminus (domains I–II) in the assembly of the initiation complex is the least understood and appears to be the most species-dependent region of the protein. Thus, in this review, we focus on the function of the N-terminus of DnaA in orisome formation and the regulation of its activity in the initiation complex in different bacteria.
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Affiliation(s)
- Anna Zawilak-Pawlik
- Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Weigla 12, Wroclaw 53-114, Poland.
| | - Małgorzata Nowaczyk
- Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Weigla 12, Wroclaw 53-114, Poland.
| | - Jolanta Zakrzewska-Czerwińska
- Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Weigla 12, Wroclaw 53-114, Poland.
- Department of Molecular Microbiology, Faculty of Biotechnology, University of Wrocław, ul. Joliot-Curie 14A, Wrocław 50-383, Poland.
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29
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Kasho K, Tanaka H, Sakai R, Katayama T. Cooperative DnaA Binding to the Negatively Supercoiled datA Locus Stimulates DnaA-ATP Hydrolysis. J Biol Chem 2016; 292:1251-1266. [PMID: 27941026 DOI: 10.1074/jbc.m116.762815] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 12/07/2016] [Indexed: 11/06/2022] Open
Abstract
Timely initiation of replication in Escherichia coli requires functional regulation of the replication initiator, ATP-DnaA. The cellular level of ATP-DnaA increases just before initiation, after which its level decreases through hydrolysis of DnaA-bound ATP, yielding initiation-inactive ADP-DnaA. Previously, we reported a novel DnaA-ATP hydrolysis system involving the chromosomal locus datA and named it datA-dependent DnaA-ATP hydrolysis (DDAH). The datA locus contains a binding site for a nucleoid-associating factor integration host factor (IHF) and a cluster of three known DnaA-binding sites, which are important for DDAH. However, the mechanisms underlying the formation and regulation of the datA-IHF·DnaA complex remain unclear. We now demonstrate that a novel DnaA box within datA is essential for ATP-DnaA complex formation and DnaA-ATP hydrolysis. Specific DnaA residues, which are important for interaction with bound ATP and for head-to-tail inter-DnaA interaction, were also required for ATP-DnaA-specific oligomer formation on datA Furthermore, we show that negative DNA supercoiling of datA stabilizes ATP-DnaA oligomers, and stimulates datA-IHF interaction and DnaA-ATP hydrolysis. Relaxation of DNA supercoiling by the addition of novobiocin, a DNA gyrase inhibitor, inhibits datA function in cells. On the basis of these results, we propose a mechanistic model of datA-IHF·DnaA complex formation and DNA supercoiling-dependent regulation for DDAH.
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Affiliation(s)
- Kazutoshi Kasho
- From the Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Hiroyuki Tanaka
- From the Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Ryuji Sakai
- From the Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Tsutomu Katayama
- From the Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
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30
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Near-atomic structural model for bacterial DNA replication initiation complex and its functional insights. Proc Natl Acad Sci U S A 2016; 113:E8021-E8030. [PMID: 27911788 DOI: 10.1073/pnas.1609649113] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Upon DNA replication initiation in Escherichia coli, the initiator protein DnaA forms higher-order complexes with the chromosomal origin oriC and a DNA-bending protein IHF. Although tertiary structures of DnaA and IHF have previously been elucidated, dynamic structures of oriC-DnaA-IHF complexes remain unknown. Here, combining computer simulations with biochemical assays, we obtained models at almost-atomic resolution for the central part of the oriC-DnaA-IHF complex. This complex can be divided into three subcomplexes; the left and right subcomplexes include pentameric DnaA bound in a head-to-tail manner and the middle subcomplex contains only a single DnaA. In the left and right subcomplexes, DnaA ATPases associated with various cellular activities (AAA+) domain III formed helices with specific structural differences in interdomain orientations, provoking a bend in the bound DNA. In the left subcomplex a continuous DnaA chain exists, including insertion of IHF into the DNA looping, consistent with the DNA unwinding function of the complex. The intervening spaces in those subcomplexes are crucial for DNA unwinding and loading of DnaB helicases. Taken together, this model provides a reasonable near-atomic level structural solution of the initiation complex, including the dynamic conformations and spatial arrangements of DnaA subcomplexes.
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31
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Jaworski P, Donczew R, Mielke T, Thiel M, Oldziej S, Weigel C, Zawilak-Pawlik A. Unique and Universal Features of Epsilonproteobacterial Origins of Chromosome Replication and DnaA-DnaA Box Interactions. Front Microbiol 2016; 7:1555. [PMID: 27746772 PMCID: PMC5043019 DOI: 10.3389/fmicb.2016.01555] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 09/16/2016] [Indexed: 12/23/2022] Open
Abstract
In bacteria, chromosome replication is initiated by the interaction of the initiator protein DnaA with a defined region of a chromosome at which DNA replication starts (oriC). While DnaA proteins share significant homology regardless of phylogeny, oriC regions exhibit more variable structures. The general architecture of oriCs is universal, i.e., they are composed of a cluster of DnaA binding sites, a DNA-unwinding element, and sequences that bind regulatory proteins. However, detailed structures of oriCs are shared by related species while being significantly different in unrelated bacteria. In this work, we characterized Epsilonproteobacterial oriC regions. Helicobacter pylori was the only species of the class for which oriC was characterized. A few unique features were found such as bipartite oriC structure, not encountered in any other Gram-negative species, and topology-sensitive DnaA-DNA interactions, which have not been found in any other bacterium. These unusual H. pylori oriC features raised questions of whether oriC structure and DnaA-DNA interactions are unique to this bacterium or whether they are common to related species. By in silico and in vitro analyses we identified putative oriCs in three Epsilonproteobacterial species: pathogenic Arcobacter butzleri, symbiotic Wolinella succinogenes, and free-living Sulfurimonas denitrificans. We propose that oriCs typically co-localize with ruvC-dnaA-dnaN in Epsilonproteobacteria, with the exception of Helicobacteriaceae species. The clusters of DnaA boxes localize upstream (oriC1) and downstream (oriC2) of dnaA, and they likely constitute bipartite origins. In all cases, DNA unwinding was shown to occur in oriC2. Unlike the DnaA box pattern, which is not conserved in Epsilonproteobacterial oriCs, the consensus DnaA box sequences and the mode of DnaA-DnaA box interactions are common to the class. We propose that the typical Epsilonproteobacterial DnaA box consists of the core nucleotide sequence 5′-TTCAC-3′ (4–8 nt), which, together with the significant changes in the DNA-binding motif of corresponding DnaAs, determines the unique molecular mechanism of DnaA-DNA interaction. Our results will facilitate identification of oriCs and subsequent identification of factors which regulate chromosome replication in other Epsilonproteobacteria. Since replication is controlled at the initiation step, it will help to better characterize life cycles of these species, many of which are considered as emerging pathogens.
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Affiliation(s)
- Pawel Jaworski
- Department of Microbiology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences Wrocław, Poland
| | - Rafal Donczew
- Department of Microbiology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences Wrocław, Poland
| | | | - Marcel Thiel
- Laboratory of Biopolymers Structure, Intercollegiate Faculty of Biotechnology, University of Gdańsk and Medical University of Gdańsk Gdańsk, Poland
| | - Stanislaw Oldziej
- Laboratory of Biopolymers Structure, Intercollegiate Faculty of Biotechnology, University of Gdańsk and Medical University of Gdańsk Gdańsk, Poland
| | - Christoph Weigel
- Department of Life Science Engineering, Fachbereich 2, HTW Berlin Berlin, Germany
| | - Anna Zawilak-Pawlik
- Department of Microbiology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences Wrocław, Poland
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32
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Wegrzyn KE, Gross M, Uciechowska U, Konieczny I. Replisome Assembly at Bacterial Chromosomes and Iteron Plasmids. Front Mol Biosci 2016; 3:39. [PMID: 27563644 PMCID: PMC4980987 DOI: 10.3389/fmolb.2016.00039] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 07/25/2016] [Indexed: 11/13/2022] Open
Abstract
The proper initiation and occurrence of DNA synthesis depends on the formation and rearrangements of nucleoprotein complexes within the origin of DNA replication. In this review article, we present the current knowledge on the molecular mechanism of replication complex assembly at the origin of bacterial chromosome and plasmid replicon containing direct repeats (iterons) within the origin sequence. We describe recent findings on chromosomal and plasmid replication initiators, DnaA and Rep proteins, respectively, and their sequence-specific interactions with double- and single-stranded DNA. Also, we discuss the current understanding of the activities of DnaA and Rep proteins required for replisome assembly that is fundamental to the duplication and stability of genetic information in bacterial cells.
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Affiliation(s)
- Katarzyna E Wegrzyn
- Department of Molecular and Cellular Biology, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk Gdansk, Poland
| | - Marta Gross
- Department of Molecular and Cellular Biology, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk Gdansk, Poland
| | - Urszula Uciechowska
- Department of Molecular and Cellular Biology, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk Gdansk, Poland
| | - Igor Konieczny
- Department of Molecular and Cellular Biology, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk Gdansk, Poland
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33
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Riber L, Frimodt-Møller J, Charbon G, Løbner-Olesen A. Multiple DNA Binding Proteins Contribute to Timing of Chromosome Replication in E. coli. Front Mol Biosci 2016; 3:29. [PMID: 27446932 PMCID: PMC4924351 DOI: 10.3389/fmolb.2016.00029] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 06/14/2016] [Indexed: 11/24/2022] Open
Abstract
Chromosome replication in Escherichia coli is initiated from a single origin, oriC. Initiation involves a number of DNA binding proteins, but only DnaA is essential and specific for the initiation process. DnaA is an AAA+ protein that binds both ATP and ADP with similar high affinities. DnaA associated with either ATP or ADP binds to a set of strong DnaA binding sites in oriC, whereas only DnaAATP is capable of binding additional and weaker sites to promote initiation. Additional DNA binding proteins act to ensure that initiation occurs timely by affecting either the cellular mass at which DNA replication is initiated, or the time window in which all origins present in a single cell are initiated, i.e. initiation synchrony, or both. Overall, these DNA binding proteins modulate the initiation frequency from oriC by: (i) binding directly to oriC to affect DnaA binding, (ii) altering the DNA topology in or around oriC, (iii) altering the nucleotide bound status of DnaA by interacting with non-coding chromosomal sequences, distant from oriC, that are important for DnaA activity. Thus, although DnaA is the key protein for initiation of replication, other DNA-binding proteins act not only on oriC for modulation of its activity but also at additional regulatory sites to control the nucleotide bound status of DnaA. Here we review the contribution of key DNA binding proteins to the tight regulation of chromosome replication in E. coli cells.
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Affiliation(s)
- Leise Riber
- Section for Functional Genomics and Center for Bacterial Stress Response and Persistence, Department of Biology, University of Copenhagen Copenhagen, Denmark
| | - Jakob Frimodt-Møller
- Section for Functional Genomics and Center for Bacterial Stress Response and Persistence, Department of Biology, University of Copenhagen Copenhagen, Denmark
| | - Godefroid Charbon
- Section for Functional Genomics and Center for Bacterial Stress Response and Persistence, Department of Biology, University of Copenhagen Copenhagen, Denmark
| | - Anders Løbner-Olesen
- Section for Functional Genomics and Center for Bacterial Stress Response and Persistence, Department of Biology, University of Copenhagen Copenhagen, Denmark
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Noguchi Y, Katayama T. The Escherichia coli Cryptic Prophage Protein YfdR Binds to DnaA and Initiation of Chromosomal Replication Is Inhibited by Overexpression of the Gene Cluster yfdQ-yfdR-yfdS-yfdT. Front Microbiol 2016; 7:239. [PMID: 26973617 PMCID: PMC4776307 DOI: 10.3389/fmicb.2016.00239] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 02/15/2016] [Indexed: 01/09/2023] Open
Abstract
The initiation of bacterial chromosomal replication is regulated by multiple pathways. To explore novel regulators, we isolated multicopy suppressors for the cold-sensitive hda-185 ΔsfiA(sulA) mutant. Hda is crucial for the negative regulation of the initiator DnaA and the hda-185 mutation causes severe replication overinitiation at the replication origin oriC. The SOS-associated division inhibitor SfiA inhibits FtsZ ring formation, an essential step for cell division regulation during the SOS response, and ΔsfiA enhances the cold sensitivity of hda-185 cells in colony formation. One of the suppressors comprised the yfdQ-yfdR-yfdS-yfdT gene cluster carried on a cryptic prophage. Increased copy numbers of yfdQRT or yfdQRS inhibited not only hda-185-dependent overinitiation, but also replication overinitiation in a hyperactive dnaA mutant, and in a mutant lacking an oriC-binding initiation-inhibitor SeqA. In addition, increasing the copy number of the gene set inhibited the growth of cells bearing specific, initiation-impairing dnaA mutations. In wild-type cells, multicopy supply of yfdQRT or yfdQRS also inhibited replication initiation and increased hydroxyurea (HU)-resistance, as seen in cells lacking DiaA, a stimulator of DnaA assembly on oriC. Deletion of the yfdQ-yfdR-yfdS-yfdT genes did not affect either HU resistance or initiation regulation. Furthermore, we found that DnaA bound specifically to YfdR in soluble protein extracts oversupplied with YfdQRST. Purified YfdR also bound to DnaA, and DnaA Phe46, an amino acid residue crucial for DnaA interactions with DiaA and DnaB replicative helicase was important for this interaction. Consistently, YfdR moderately inhibited DiaA-DnaA and DnaB-DnaA interactions. In addition, protein extracts oversupplied with YfdQRST inhibited replication initiation in vitro. Given the roles of yfdQ and yfdS in cell tolerance to specific environmental stresses, the yfdQ-yfdR-yfdS-yfdT genes might downregulate the initiator DnaA-oriC complex under specific growth conditions.
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Affiliation(s)
- Yasunori Noguchi
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University Fukuoka, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University Fukuoka, Japan
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Abstract
Hexameric helicases control both the initiation and the elongation phase of DNA replication. The toroidal structure of these enzymes provides an inherent challenge in the opening and loading onto DNA at origins, as well as the conformational changes required to exclude one strand from the central channel and activate DNA unwinding. Recently, high-resolution structures have not only revealed the architecture of various hexameric helicases but also detailed the interactions of DNA within the central channel, as well as conformational changes that occur during loading. This structural information coupled with advanced biochemical reconstitutions and biophysical methods have transformed our understanding of the dynamics of both the helicase structure and the DNA interactions required for efficient unwinding at the replisome.
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Affiliation(s)
- Michael A Trakselis
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas, 76798, USA
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36
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Noguchi Y, Sakiyama Y, Kawakami H, Katayama T. The Arg Fingers of Key DnaA Protomers Are Oriented Inward within the Replication Origin oriC and Stimulate DnaA Subcomplexes in the Initiation Complex. J Biol Chem 2015; 290:20295-312. [PMID: 26126826 DOI: 10.1074/jbc.m115.662601] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Indexed: 01/01/2023] Open
Abstract
ATP-DnaA binds to multiple DnaA boxes in the Escherichia coli replication origin (oriC) and forms left-half and right-half subcomplexes that promote DNA unwinding and DnaB helicase loading. DnaA forms homo-oligomers in a head-to-tail manner via interactions between the bound ATP and Arg-285 of the adjacent protomer. DnaA boxes R1 and R4 reside at the outer edges of the DnaA-binding region and have opposite orientations. In this study, roles for the protomers bound at R1 and R4 were elucidated using chimeric DnaA molecules that had alternative DNA binding sequence specificity and chimeric oriC molecules bearing the alternative DnaA binding sequence at R1 or R4. In vitro, protomers at R1 and R4 promoted initiation regardless of whether the bound nucleotide was ADP or ATP. Arg-285 was shown to play an important role in the formation of subcomplexes that were active in oriC unwinding and DnaB loading. The results of in vivo analysis using the chimeric molecules were consistent with the in vitro data. Taken together, the data suggest a model in which DnaA subcomplexes form in symmetrically opposed orientations and in which the Arg-285 fingers face inward to mediate interactions with adjacent protomers. This mode is consistent with initiation regulation by ATP-DnaA and bidirectional loading of DnaB helicases.
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Affiliation(s)
- Yasunori Noguchi
- From the Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Yukari Sakiyama
- From the Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Hironori Kawakami
- From the Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Tsutomu Katayama
- From the Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
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Leonard AC, Grimwade JE. The orisome: structure and function. Front Microbiol 2015; 6:545. [PMID: 26082765 PMCID: PMC4451416 DOI: 10.3389/fmicb.2015.00545] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 05/18/2015] [Indexed: 11/15/2022] Open
Abstract
During the cell division cycle of all bacteria, DNA-protein complexes termed orisomes trigger the onset of chromosome duplication. Orisome assembly is both staged and stringently regulated to ensure that DNA synthesis begins at a precise time and only once at each origin per cycle. Orisomes comprise multiple copies of the initiator protein DnaA, which oligomerizes after interacting with specifically positioned recognition sites in the unique chromosomal replication origin, oriC. Since DnaA is highly conserved, it is logical to expect that all bacterial orisomes will share fundamental attributes. Indeed, although mechanistic details remain to be determined, all bacterial orisomes are capable of unwinding oriC DNA and assisting with loading of DNA helicase onto the single-strands. However, comparative analysis of oriCs reveals that the arrangement and number of DnaA recognition sites is surprisingly variable among bacterial types, suggesting there are many paths to produce functional orisome complexes. Fundamental questions exist about why these different paths exist and which features of orisomes must be shared among diverse bacterial types. In this review we present the current understanding of orisome assembly and function in Escherichia coli and compare the replication origins among the related members of the Gammaproteobacteria. From this information we propose that the diversity in orisome assembly reflects both the requirement to regulate the conformation of origin DNA as well as to provide an appropriate cell cycle timing mechanism that reflects the lifestyle of the bacteria. We suggest that identification of shared steps in orisome assembly may reveal particularly good targets for new antibiotics.
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Affiliation(s)
- Alan C Leonard
- Department of Biological Sciences, Florida Institute of Technology, Melbourne FL, USA
| | - Julia E Grimwade
- Department of Biological Sciences, Florida Institute of Technology, Melbourne FL, USA
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Helgesen E, Fossum-Raunehaug S, Sætre F, Schink KO, Skarstad K. Dynamic Escherichia coli SeqA complexes organize the newly replicated DNA at a considerable distance from the replisome. Nucleic Acids Res 2015; 43:2730-43. [PMID: 25722374 PMCID: PMC4357733 DOI: 10.1093/nar/gkv146] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Escherichia coli SeqA protein binds to newly replicated, hemimethylated DNA behind replication forks and forms structures consisting of several hundred SeqA molecules bound to about 100 kb of DNA. It has been suggested that SeqA structures either direct the new sister DNA molecules away from each other or constitute a spacer that keeps the sisters together. We have developed an image analysis script that automatically measures the distance between neighboring foci in cells. Using this tool as well as direct stochastic optical reconstruction microscopy (dSTORM) we find that in cells with fluorescently tagged SeqA and replisome the sister SeqA structures were situated close together (less than about 30 nm apart) and relatively far from the replisome (on average 200–300 nm). The results support the idea that newly replicated sister molecules are kept together behind the fork and suggest the existence of a stretch of DNA between the replisome and SeqA which enjoys added stabilization. This could be important in facilitating DNA transactions such as recombination, mismatch repair and topoisomerase activity. In slowly growing cells without ongoing replication forks the SeqA protein was found to reside at the fully methylated origins prior to initiation of replication.
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Affiliation(s)
- Emily Helgesen
- Department of Cell Biology, Institute for Cancer Research, Oslo University Hospital, Radiumhospitalet, 0310 Oslo, Norway
| | - Solveig Fossum-Raunehaug
- Department of Cell Biology, Institute for Cancer Research, Oslo University Hospital, Radiumhospitalet, 0310 Oslo, Norway School of Pharmacy, Faculty of Mathematics and Natural Sciences, University of Oslo, 0316 Oslo, Norway
| | - Frank Sætre
- Department of Cell Biology, Institute for Cancer Research, Oslo University Hospital, Radiumhospitalet, 0310 Oslo, Norway
| | - Kay Oliver Schink
- Department of Biochemistry, Institute for Cancer Research, Oslo University Hospital, Radiumhospitalet, 0310 Oslo, Norway
| | - Kirsten Skarstad
- Department of Cell Biology, Institute for Cancer Research, Oslo University Hospital, Radiumhospitalet, 0310 Oslo, Norway School of Pharmacy, Faculty of Mathematics and Natural Sciences, University of Oslo, 0316 Oslo, Norway
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Donczew R, Makowski Ł, Jaworski P, Bezulska M, Nowaczyk M, Zakrzewska-Czerwińska J, Zawilak-Pawlik A. The atypical response regulator HP1021 controls formation of the Helicobacter pylori replication initiation complex. Mol Microbiol 2014; 95:297-312. [PMID: 25402746 DOI: 10.1111/mmi.12866] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/12/2014] [Indexed: 12/15/2022]
Abstract
The replication of a bacterial chromosome is initiated by the DnaA protein, which binds to the specific chromosomal region oriC and unwinds duplex DNA within the DNA-unwinding element (DUE). The initiation is tightly regulated by many factors, which control either DnaA or oriC activity and ensure that the chromosome is duplicated only when the conditions favor the survival of daughter cells. The factors controlling oriC activity often belong to the protein families of two-component systems. Here, we found that Helicobacter pylori oriC activity is controlled by HP1021, a member of the atypical response regulator family. HP1021 protein specifically interacts with H. pylori oriC at HP1021 boxes (5'-TGTT[TA]C[TA]-3'), which overlap with three modules important for oriC function: DnaA boxes, the hypersensitivity (hs) region and the DUE. Consequently, HP1021 binding to oriC precludes DnaA-oriC interactions and inhibits DNA unwinding at the DUE. Thus, HP1021 constitutes a negative regulator of the H. pylori orisome assembly in vitro. Furthermore, HP1021 boxes were found upstream of at least 70 genes, including those encoding CagA and Fur proteins. We postulate that HP1021 might coordinate chromosome replication, and thus bacterial growth, with other cellular processes and conditions in the human stomach.
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Affiliation(s)
- Rafał Donczew
- Department of Microbiology, Polish Academy of Sciences, Institute of Immunology and Experimental Therapy, Weigla 12, Wrocław, 53-114, Poland
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Zabrocka E, Wegrzyn K, Konieczny I. Two replication initiators - one mechanism for replication origin opening? Plasmid 2014; 76:72-8. [PMID: 25454070 DOI: 10.1016/j.plasmid.2014.10.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 09/30/2014] [Accepted: 10/10/2014] [Indexed: 11/25/2022]
Abstract
DNA replication initiation has been well-characterized; however, studies in the past few years have shown that there are still important discoveries to be made. Recent publications concerning the bacterial DnaA protein have revealed how this replication initiator, via interaction with specific sequences within the origin region, causes local destabilization of double stranded DNA. Observations made in the context of this bacterial initiator have also been converging with those recently made for plasmid Rep proteins. In this mini review we discuss the relevance of new findings for the RK2 plasmid replication initiator, TrfA, with regard to new data on the structure of complexes formed by the chromosomal replication initiator DnaA. We discuss structure-function relationships of replication initiation proteins.
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Affiliation(s)
- Elzbieta Zabrocka
- Department of Molecular and Cellular Biology, Intercollegiate Faculty of Biotechnology University of Gdansk and Medical University of Gdansk, Kladki 24, 80-822 Gdansk, Poland
| | - Katarzyna Wegrzyn
- Department of Molecular and Cellular Biology, Intercollegiate Faculty of Biotechnology University of Gdansk and Medical University of Gdansk, Kladki 24, 80-822 Gdansk, Poland
| | - Igor Konieczny
- Department of Molecular and Cellular Biology, Intercollegiate Faculty of Biotechnology University of Gdansk and Medical University of Gdansk, Kladki 24, 80-822 Gdansk, Poland.
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41
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Kasho K, Fujimitsu K, Matoba T, Oshima T, Katayama T. Timely binding of IHF and Fis to DARS2 regulates ATP-DnaA production and replication initiation. Nucleic Acids Res 2014; 42:13134-49. [PMID: 25378325 PMCID: PMC4245941 DOI: 10.1093/nar/gku1051] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
In Escherichia coli, the ATP-bound form of DnaA (ATP-DnaA) promotes replication initiation. During replication, the bound ATP is hydrolyzed to ADP to yield the ADP-bound form (ADP-DnaA), which is inactive for initiation. The chromosomal site DARS2 facilitates the regeneration of ATP-DnaA by catalyzing nucleotide exchange between free ATP and ADP bound to DnaA. However, the regulatory mechanisms governing this exchange reaction are unclear. Here, using in vitro reconstituted experiments, we show that two nucleoid-associated proteins, IHF and Fis, bind site-specifically to DARS2 to activate coordinately the exchange reaction. The regenerated ATP-DnaA was fully active in replication initiation and underwent DnaA-ATP hydrolysis. ADP-DnaA formed heteromultimeric complexes with IHF and Fis on DARS2, and underwent nucleotide dissociation more efficiently than ATP-DnaA. Consistently, mutant analyses demonstrated that specific binding of IHF and Fis to DARS2 stimulates the formation of ATP-DnaA production, thereby promoting timely initiation. Moreover, we show that IHF-DARS2 binding is temporally regulated during the cell cycle, whereas Fis only binds to DARS2 in exponentially growing cells. These results elucidate the regulation of ATP-DnaA and replication initiation in coordination with the cell cycle and growth phase.
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Affiliation(s)
- Kazutoshi Kasho
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Kazuyuki Fujimitsu
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Toshihiro Matoba
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Taku Oshima
- Division of Genomics of Bacterial Cell Functions, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
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42
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Wolański M, Jakimowicz D, Zakrzewska-Czerwińska J. Fifty years after the replicon hypothesis: cell-specific master regulators as new players in chromosome replication control. J Bacteriol 2014; 196:2901-11. [PMID: 24914187 PMCID: PMC4135643 DOI: 10.1128/jb.01706-14] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Numerous free-living bacteria undergo complex differentiation in response to unfavorable environmental conditions or as part of their natural cell cycle. Developmental programs require the de novo expression of several sets of genes responsible for morphological, physiological, and metabolic changes, such as spore/endospore formation, the generation of flagella, and the synthesis of antibiotics. Notably, the frequency of chromosomal replication initiation events must also be adjusted with respect to the developmental stage in order to ensure that each nascent cell receives a single copy of the chromosomal DNA. In this review, we focus on the master transcriptional factors, Spo0A, CtrA, and AdpA, which coordinate developmental program and which were recently demonstrated to control chromosome replication. We summarize the current state of knowledge on the role of these developmental regulators in synchronizing the replication with cell differentiation in Bacillus subtilis, Caulobacter crescentus, and Streptomyces coelicolor, respectively.
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Affiliation(s)
- Marcin Wolański
- Faculty of Biotechnology, University of Wrocław, Wrocław, Poland
| | - Dagmara Jakimowicz
- Faculty of Biotechnology, University of Wrocław, Wrocław, Poland Department of Microbiology, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland
| | - Jolanta Zakrzewska-Czerwińska
- Faculty of Biotechnology, University of Wrocław, Wrocław, Poland Department of Microbiology, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland
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Donczew R, Mielke T, Jaworski P, Zakrzewska-Czerwińska J, Zawilak-Pawlik A. Assembly of Helicobacter pylori initiation complex is determined by sequence-specific and topology-sensitive DnaA-oriC interactions. J Mol Biol 2014; 426:2769-82. [PMID: 24862285 DOI: 10.1016/j.jmb.2014.05.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Revised: 05/15/2014] [Accepted: 05/16/2014] [Indexed: 10/25/2022]
Abstract
In bacteria, chromosome replication is initiated by binding of the DnaA initiator protein to DnaA boxes located in the origin of chromosomal replication (oriC). This leads to DNA helix opening within the DNA-unwinding element. Helicobacter pylori oriC, the first bipartite origin identified in Gram-negative bacteria, contains two subregions, oriC1 and oriC2, flanking the dnaA gene. The DNA-unwinding element region is localized in the oriC2 subregion downstream of dnaA. Surprisingly, oriC2-DnaA interactions were shown to depend on DNA topology, which is unusual in bacteria but is similar to initiator-origin interactions observed in higher organisms. In this work, we identified three DnaA boxes in the oriC2 subregion, two of which were bound only as supercoiled DNA. We found that all three DnaA boxes play important roles in orisome assembly and subsequent DNA unwinding, but different functions can be assigned to individual boxes. This suggests that the H. pylori oriC may be functionally divided, similar to what was described recently for Escherichia coli oriC. On the basis of these results, we propose a model of initiation complex formation in H. pylori.
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Affiliation(s)
- Rafał Donczew
- Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Department of Microbiology, Weigla 12, 53-114 Wrocław, Poland.
| | - Thorsten Mielke
- Max Planck Institute for Molecular Genetics, Ihnestrasse 63-73, 14195 Berlin, Germany.
| | - Paweł Jaworski
- Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Department of Microbiology, Weigla 12, 53-114 Wrocław, Poland.
| | - Jolanta Zakrzewska-Czerwińska
- Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Department of Microbiology, Weigla 12, 53-114 Wrocław, Poland; University of Wrocław, Faculty of Biotechnology, Joliot-Curie 14a, 50-138 Wrocław, Poland.
| | - Anna Zawilak-Pawlik
- Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Department of Microbiology, Weigla 12, 53-114 Wrocław, Poland.
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Wegrzyn K, Fuentes-Perez ME, Bury K, Rajewska M, Moreno-Herrero F, Konieczny I. Sequence-specific interactions of Rep proteins with ssDNA in the AT-rich region of the plasmid replication origin. Nucleic Acids Res 2014; 42:7807-18. [PMID: 24838560 PMCID: PMC4081077 DOI: 10.1093/nar/gku453] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
The DNA unwinding element (DUE) is a sequence rich in adenine and thymine residues present within the origin region of both prokaryotic and eukaryotic replicons. Recently, it has been shown that this is the site where bacterial DnaA proteins, the chromosomal replication initiators, form a specific nucleoprotein filament. DnaA proteins contain a DNA binding domain (DBD) and belong to the family of origin binding proteins (OBPs). To date there has been no data on whether OBPs structurally different from DnaA can form nucleoprotein complexes within the DUE. In this work we demonstrate that plasmid Rep proteins, composed of two Winged Helix domains, distinct from the DBD, specifically bind to one of the strands of ssDNA within the DUE. We observed nucleoprotein complexes formed by these Rep proteins, involving both dsDNA containing the Rep-binding sites (iterons) and the strand-specific ssDNA of the DUE. Formation of these complexes required the presence of all repeated sequence elements located within the DUE. Any changes in these repeated sequences resulted in the disturbance in Rep-ssDNA DUE complex formation and the lack of origin replication activity in vivo or in vitro.
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Affiliation(s)
- Katarzyna Wegrzyn
- Department of Molecular and Cellular Biology, Intercollegiate Faculty of Biotechnology, University of Gdansk, 24 Kladki, 80-822 Gdansk, Poland
| | - Maria Eugenia Fuentes-Perez
- Department of Macromolecular Structures, Centro Nacional de Biotecnologia, CSIC, Darwin 3, 28049 Cantoblanco, Madrid, Spain
| | - Katarzyna Bury
- Department of Molecular and Cellular Biology, Intercollegiate Faculty of Biotechnology, University of Gdansk, 24 Kladki, 80-822 Gdansk, Poland
| | - Magdalena Rajewska
- Department of Molecular and Cellular Biology, Intercollegiate Faculty of Biotechnology, University of Gdansk, 24 Kladki, 80-822 Gdansk, Poland
| | - Fernando Moreno-Herrero
- Department of Macromolecular Structures, Centro Nacional de Biotecnologia, CSIC, Darwin 3, 28049 Cantoblanco, Madrid, Spain
| | - Igor Konieczny
- Department of Molecular and Cellular Biology, Intercollegiate Faculty of Biotechnology, University of Gdansk, 24 Kladki, 80-822 Gdansk, Poland
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45
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Donczew R, Zakrzewska-Czerwińska J, Zawilak-Pawlik A. Beyond DnaA: the role of DNA topology and DNA methylation in bacterial replication initiation. J Mol Biol 2014; 426:2269-82. [PMID: 24747048 DOI: 10.1016/j.jmb.2014.04.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 04/10/2014] [Accepted: 04/11/2014] [Indexed: 12/31/2022]
Abstract
The replication of chromosomal DNA is a fundamental event in the life cycle of every cell. The first step of replication, initiation, is controlled by multiple factors to ensure only one round of replication per cell cycle. The process of initiation has been described most thoroughly for bacteria, especially Escherichia coli, and involves many regulatory proteins that vary considerably between different species. These proteins control the activity of the two key players of initiation in bacteria: the initiator protein DnaA and the origin of chromosome replication (oriC). Factors involved in the control of the availability, activity, or oligomerization of DnaA during initiation are generally regarded as the most important and thus have been thoroughly characterized. Other aspects of the initiation process, such as origin accessibility and susceptibility to unwinding, have been less explored. However, recent findings indicate that these factors have a significant role. This review focuses on DNA topology, conformation, and methylation as important factors that regulate the initiation process in bacteria. We present a comprehensive summary of the factors involved in the modulation of DNA topology, both locally at oriC and more globally at the level of the entire chromosome. We show clearly that the conformation of oriC dynamically changes, and control of this conformation constitutes another, important factor in the regulation of bacterial replication initiation. Furthermore, the process of initiation appears to be associated with the dynamics of the entire chromosome and this association is an important but largely unexplored phenomenon.
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Affiliation(s)
- Rafał Donczew
- Institute of Immunology and Experimental Therapy, Department of Microbiology, Polish Academy of Sciences, Weigla 12, 53-114 Wrocław, Poland.
| | - Jolanta Zakrzewska-Czerwińska
- Institute of Immunology and Experimental Therapy, Department of Microbiology, Polish Academy of Sciences, Weigla 12, 53-114 Wrocław, Poland; Faculty of Biotechnology, University of Wrocław, Joliot-Curie 14a, 50-138 Wrocław, Poland.
| | - Anna Zawilak-Pawlik
- Institute of Immunology and Experimental Therapy, Department of Microbiology, Polish Academy of Sciences, Weigla 12, 53-114 Wrocław, Poland.
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Kaur G, Vora MP, Czerwonka CA, Rozgaja TA, Grimwade JE, Leonard AC. Building the bacterial orisome: high-affinity DnaA recognition plays a role in setting the conformation of oriC DNA. Mol Microbiol 2014; 91:1148-63. [PMID: 24443848 DOI: 10.1111/mmi.12525] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/16/2014] [Indexed: 11/29/2022]
Abstract
During assembly of the E. coli pre-replicative complex (pre-RC), initiator DnaA oligomers are nucleated from three widely separated high-affinity DnaA recognition sites in oriC. Oligomer assembly is then guided by low-affinity DnaA recognition sites, but is also regulated by a switch-like conformational change in oriC mediated by sequential binding of two DNA bending proteins, Fis and IHF, serving as inhibitor and activator respectively. Although their recognition sites are separated by up to 90 bp, Fis represses IHF binding and weak DnaA interactions until accumulating DnaA displaces Fis from oriC. It remains unclear whether high-affinity DnaA binding plays any role in Fis repression at a distance and it is also not known whether all high-affinity DnaA recognition sites play an equivalent role in oligomer formation. To examine these issues, we developed origin-selective recombineering methods to mutate E. coli chromosomal oriC. We found that, although oligomers were assembled in the absence of any individual high-affinity DnaA binding site, loss of DnaA binding at peripheral sites eliminated Fis repression, and made binding of both Fis and IHF essential. We propose a model in which interaction of DnaA molecules at high-affinity sites regulates oriC DNA conformation.
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Affiliation(s)
- Gulpreet Kaur
- Department of Biological Sciences, Florida Institute of Technology, 150 West University Boulevard, Melbourne, FL, 32901, USA
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Su'etsugu M, Harada Y, Keyamura K, Matsunaga C, Kasho K, Abe Y, Ueda T, Katayama T. The DnaA N-terminal domain interacts with Hda to facilitate replicase clamp-mediated inactivation of DnaA. Environ Microbiol 2013; 15:3183-95. [PMID: 23679057 DOI: 10.1111/1462-2920.12147] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 03/17/2013] [Indexed: 11/28/2022]
Abstract
DnaA activity for replication initiation of the Escherichia coli chromosome is negatively regulated by feedback from the DNA-loaded form of the replicase clamp. In this process, called RIDA (regulatory inactivation of DnaA), ATP-bound DnaA transiently assembles into a complex consisting of Hda and the DNA-clamp, which promotes inter-AAA+ domain association between Hda and DnaA and stimulates hydrolysis of DnaA-bound ATP, producing inactive ADP-DnaA. Using a truncated DnaA mutant, we previously demonstrated that the DnaA N-terminal domain is involved in RIDA. However, the precise role of the N-terminal domain in RIDA has remained largely unclear. Here, we used an in vitro reconstituted system to demonstrate that the Asn-44 residue in the N-terminal domain of DnaA is crucial for RIDA but not for replication initiation. Moreover, an assay termed PDAX (pull-down after cross-linking) revealed an unstable interaction between a DnaA-N44A mutant and Hda. In vivo, this mutant exhibited an increase in the cellular level of ATP-bound DnaA. These results establish a model in which interaction between DnaA Asn-44 and Hda stabilizes the association between the AAA+ domains of DnaA and Hda to facilitate DnaA-ATP hydrolysis during RIDA.
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Affiliation(s)
- Masayuki Su'etsugu
- Department of Molecular Biology, Kyushu University Graduate School of Pharmaceutical Sciences, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
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