1
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Peñafiel-Ayala A, Peralta-Castro A, Mora-Garduño J, García-Medel P, Zambrano-Pereira AG, Díaz-Quezada C, Abraham-Juárez MJ, Benítez-Cardoza CG, Sloan DB, Brieba LG. Plant Organellar MSH1 Is a Displacement Loop-Specific Endonuclease. PLANT & CELL PHYSIOLOGY 2024; 65:560-575. [PMID: 37756637 DOI: 10.1093/pcp/pcad112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 09/09/2023] [Accepted: 09/19/2023] [Indexed: 09/29/2023]
Abstract
MutS HOMOLOG 1 (MSH1) is an organellar-targeted protein that obstructs ectopic recombination and the accumulation of mutations in plant organellar genomes. MSH1 also modulates the epigenetic status of nuclear DNA, and its absence induces a variety of phenotypic responses. MSH1 is a member of the MutS family of DNA mismatch repair proteins but harbors an additional GIY-YIG nuclease domain that distinguishes it from the rest of this family. How MSH1 hampers recombination and promotes fidelity in organellar DNA inheritance is unknown. Here, we elucidate its enzymatic activities by recombinantly expressing and purifying full-length MSH1 from Arabidopsis thaliana (AtMSH1). AtMSH1 is a metalloenzyme that shows a strong binding affinity for displacement loops (D-loops). The DNA-binding abilities of AtMSH1 reside in its MutS domain and not in its GIY-YIG domain, which is the ancillary nickase of AtMSH1. In the presence of divalent metal ions, AtMSH1 selectively executes multiple incisions at D-loops, but not other DNA structures including Holliday junctions or dsDNA, regardless of the presence or absence of mismatches. The selectivity of AtMSH1 to dismantle D-loops supports the role of this enzyme in preventing recombination between short repeats. Our results suggest that plant organelles have evolved novel DNA repair routes centered around the anti-recombinogenic activity of MSH1.
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Affiliation(s)
- Alejandro Peñafiel-Ayala
- Langebio-Cinvestav Sede Irapuato, Km. 9.6 Libramiento Norte Carretera. Irapuato-León, Irapuato, Guanajuato 36821, México
| | - Antolin Peralta-Castro
- Langebio-Cinvestav Sede Irapuato, Km. 9.6 Libramiento Norte Carretera. Irapuato-León, Irapuato, Guanajuato 36821, México
| | - Josue Mora-Garduño
- Langebio-Cinvestav Sede Irapuato, Km. 9.6 Libramiento Norte Carretera. Irapuato-León, Irapuato, Guanajuato 36821, México
| | - Paola García-Medel
- Langebio-Cinvestav Sede Irapuato, Km. 9.6 Libramiento Norte Carretera. Irapuato-León, Irapuato, Guanajuato 36821, México
| | - Angie G Zambrano-Pereira
- Langebio-Cinvestav Sede Irapuato, Km. 9.6 Libramiento Norte Carretera. Irapuato-León, Irapuato, Guanajuato 36821, México
| | - Corina Díaz-Quezada
- Langebio-Cinvestav Sede Irapuato, Km. 9.6 Libramiento Norte Carretera. Irapuato-León, Irapuato, Guanajuato 36821, México
| | - María Jazmín Abraham-Juárez
- Langebio-Cinvestav Sede Irapuato, Km. 9.6 Libramiento Norte Carretera. Irapuato-León, Irapuato, Guanajuato 36821, México
| | - Claudia G Benítez-Cardoza
- Laboratorio de Investigación Bioquímica, Programa Institucional en Biomedicina Molecular ENMyH-IPN, Guillermo Massieu Helguera No. 239, La Escalera Ticoman 07320 DF, México
| | - Daniel B Sloan
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Luis G Brieba
- Langebio-Cinvestav Sede Irapuato, Km. 9.6 Libramiento Norte Carretera. Irapuato-León, Irapuato, Guanajuato 36821, México
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2
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Shi C, Wang L, Xu H, Zhao Y, Tian B, Hua Y. Characterization of a Novel N4-Methylcytosine Restriction-Modification System in Deinococcus radiodurans. Int J Mol Sci 2024; 25:1660. [PMID: 38338939 PMCID: PMC10855626 DOI: 10.3390/ijms25031660] [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: 12/21/2023] [Revised: 01/22/2024] [Accepted: 01/25/2024] [Indexed: 02/12/2024] Open
Abstract
Deinococcus radiodurans is an extremophilic microorganism that possesses a unique DNA damage repair system, conferring a strong resistance to radiation, desiccation, oxidative stress, and chemical damage. Recently, we discovered that D. radiodurans possesses an N4-methylation (m4C) methyltransferase called M.DraR1, which recognizes the 5'-CCGCGG-3' sequence and methylates the second cytosine. Here, we revealed its cognate restriction endonuclease R.DraR1 and recognized that it is the only endonuclease specially for non-4C-methylated 5'-CCGCGG-3' sequence so far. We designated the particular m4C R.DraR1-M.DraR1 as the DraI R-M system. Bioinformatics searches displayed the rarity of the DraI R-M homologous system. Meanwhile, recombination and transformation efficiency experiments demonstrated the important role of the DraI R-M system in response to oxidative stress. In addition, in vitro activity experiments showed that R.DraR1 could exceptionally cleave DNA substrates with a m5C-methlated 5'-CCGCGG-3' sequence instead of its routine activity, suggesting that this particular R-M component possesses a broader substrate choice. Furthermore, an imbalance of the DraI R-M system led to cell death through regulating genes involved in the maintenance of cell survival such as genome stability, transporter, and energy production. Thus, our research revealed a novel m4C R-M system that plays key roles in maintaining cell viability and defending foreign DNA in D. radiodurans.
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Affiliation(s)
- Chenxiang Shi
- MOE Key Laboratory of Biosystems Homeostasis and Protection, Institute of Biophysics, College of Life Sciences, Zhejiang University, Hangzhou 310058, China; (C.S.); (H.X.); (Y.Z.); (B.T.)
- Cancer Center, Zhejiang University, Hangzhou 310058, China
| | - Liangyan Wang
- MOE Key Laboratory of Biosystems Homeostasis and Protection, Institute of Biophysics, College of Life Sciences, Zhejiang University, Hangzhou 310058, China; (C.S.); (H.X.); (Y.Z.); (B.T.)
- Cancer Center, Zhejiang University, Hangzhou 310058, China
| | - Hong Xu
- MOE Key Laboratory of Biosystems Homeostasis and Protection, Institute of Biophysics, College of Life Sciences, Zhejiang University, Hangzhou 310058, China; (C.S.); (H.X.); (Y.Z.); (B.T.)
- Cancer Center, Zhejiang University, Hangzhou 310058, China
| | - Ye Zhao
- MOE Key Laboratory of Biosystems Homeostasis and Protection, Institute of Biophysics, College of Life Sciences, Zhejiang University, Hangzhou 310058, China; (C.S.); (H.X.); (Y.Z.); (B.T.)
- Cancer Center, Zhejiang University, Hangzhou 310058, China
| | - Bing Tian
- MOE Key Laboratory of Biosystems Homeostasis and Protection, Institute of Biophysics, College of Life Sciences, Zhejiang University, Hangzhou 310058, China; (C.S.); (H.X.); (Y.Z.); (B.T.)
- Cancer Center, Zhejiang University, Hangzhou 310058, China
| | - Yuejin Hua
- MOE Key Laboratory of Biosystems Homeostasis and Protection, Institute of Biophysics, College of Life Sciences, Zhejiang University, Hangzhou 310058, China; (C.S.); (H.X.); (Y.Z.); (B.T.)
- Cancer Center, Zhejiang University, Hangzhou 310058, China
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3
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Doyle LA, Takushi B, Kibler RD, Milles LF, Orozco CT, Jones JD, Jackson SE, Stoddard BL, Bradley P. De novo design of knotted tandem repeat proteins. Nat Commun 2023; 14:6746. [PMID: 37875492 PMCID: PMC10598012 DOI: 10.1038/s41467-023-42388-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 10/09/2023] [Indexed: 10/26/2023] Open
Abstract
De novo protein design methods can create proteins with folds not yet seen in nature. These methods largely focus on optimizing the compatibility between the designed sequence and the intended conformation, without explicit consideration of protein folding pathways. Deeply knotted proteins, whose topologies may introduce substantial barriers to folding, thus represent an interesting test case for protein design. Here we report our attempts to design proteins with trefoil (31) and pentafoil (51) knotted topologies. We extended previously described algorithms for tandem repeat protein design in order to construct deeply knotted backbones and matching designed repeat sequences (N = 3 repeats for the trefoil and N = 5 for the pentafoil). We confirmed the intended conformation for the trefoil design by X ray crystallography, and we report here on this protein's structure, stability, and folding behaviour. The pentafoil design misfolded into an asymmetric structure (despite a 5-fold symmetric sequence); two of the four repeat-repeat units matched the designed backbone while the other two diverged to form local contacts, leading to a trefoil rather than pentafoil knotted topology. Our results also provide insights into the folding of knotted proteins.
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Affiliation(s)
- Lindsey A Doyle
- Division of Basic Sciences, Fred Hutchinson Cancer Center, 1100 Fairview Ave. North, Seattle, WA, 98109, USA
| | - Brittany Takushi
- Division of Basic Sciences, Fred Hutchinson Cancer Center, 1100 Fairview Ave. North, Seattle, WA, 98109, USA
| | - Ryan D Kibler
- Department of Biochemistry, University of Washington, Seattle, WA, 98195, USA
| | - Lukas F Milles
- Department of Biochemistry, University of Washington, Seattle, WA, 98195, USA
| | - Carolina T Orozco
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Jonathan D Jones
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Sophie E Jackson
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Barry L Stoddard
- Division of Basic Sciences, Fred Hutchinson Cancer Center, 1100 Fairview Ave. North, Seattle, WA, 98109, USA.
| | - Philip Bradley
- Division of Basic Sciences, Fred Hutchinson Cancer Center, 1100 Fairview Ave. North, Seattle, WA, 98109, USA.
- Division of Public Health Sciences and Program in Computational Biology, Fred Hutchinson Cancer Center, 1100 Fairview Ave. N, Seattle, WA, 98009, USA.
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4
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Freeman ADJ, Déclais AC, Wilson TJ, Lilley DJ. Biochemical and mechanistic analysis of the cleavage of branched DNA by human ANKLE1. Nucleic Acids Res 2023; 51:5743-5754. [PMID: 37216589 PMCID: PMC10287932 DOI: 10.1093/nar/gkad416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 03/28/2023] [Accepted: 05/04/2023] [Indexed: 05/24/2023] Open
Abstract
ANKLE1 is a nuclease that provides a final opportunity to process unresolved junctions in DNA that would otherwise create chromosomal linkages blocking cell division. It is a GIY-YIG nuclease. We have expressed an active domain of human ANKLE1 containing the GIY-YIG nuclease domain in bacteria, that is monomeric in solution and when bound to a DNA Y-junction, and unilaterally cleaves a cruciform junction. Using an AlphaFold model of the enzyme we identify the key active residues, and show that mutation of each leads to impairment of activity. There are two components in the catalytic mechanism. Cleavage rate is pH dependent, corresponding to a pKa of 6.9, suggesting an involvement of the conserved histidine in proton transfer. The reaction rate depends on the nature of the divalent cation, likely bound by glutamate and asparagine side chains, and is log-linear with the metal ion pKa. We propose that the reaction is subject to general acid-base catalysis, using a combination of tyrosine and histidine acting as general base and water directly coordinated to the metal ion as general acid. The reaction is temperature dependent; activation energy Ea = 37 kcal mol-1, suggesting that cleavage is coupled to opening of DNA in the transition state.
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Affiliation(s)
- Alasdair D J Freeman
- Nucleic Acid Structure Research Group, MSI/WTB Complex, The University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Anne-Cécile Déclais
- Nucleic Acid Structure Research Group, MSI/WTB Complex, The University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Timothy J Wilson
- Nucleic Acid Structure Research Group, MSI/WTB Complex, The University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - David M J Lilley
- Nucleic Acid Structure Research Group, MSI/WTB Complex, The University of Dundee, Dow Street, Dundee DD1 5EH, UK
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5
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Verma P, Kumari P, Negi S, Yadav G, Gaur V. Holliday junction resolution by At-HIGLE: an SLX1 lineage endonuclease from Arabidopsis thaliana with a novel in-built regulatory mechanism. Nucleic Acids Res 2022; 50:4630-4646. [PMID: 35412622 PMCID: PMC9071465 DOI: 10.1093/nar/gkac239] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 03/24/2022] [Accepted: 04/01/2022] [Indexed: 12/14/2022] Open
Abstract
Holliday junction is the key homologous recombination intermediate, resolved by structure-selective endonucleases (SSEs). SLX1 is the most promiscuous SSE of the GIY-YIG nuclease superfamily. In fungi and animals, SLX1 nuclease activity relies on a non-enzymatic partner, SLX4, but no SLX1-SLX4 like complex has ever been characterized in plants. Plants exhibit specialized DNA repair and recombination machinery. Based on sequence similarity with the GIY-YIG nuclease domain of SLX1 proteins from fungi and animals, At-HIGLE was identified to be a possible SLX1 like nuclease from plants. Here, we elucidated the crystal structure of the At-HIGLE nuclease domain from Arabidopsis thaliana, establishing it as a member of the SLX1-lineage of the GIY-YIG superfamily with structural changes in DNA interacting regions. We show that At-HIGLE can process branched-DNA molecules without an SLX4 like protein. Unlike fungal SLX1, At-HIGLE exists as a catalytically active homodimer capable of generating two coordinated nicks during HJ resolution. Truncating the extended C-terminal region of At-HIGLE increases its catalytic activity, changes the nicking pattern, and monomerizes At-HIGLE. Overall, we elucidated the first structure of a plant SLX1-lineage protein, showed its HJ resolving activity independent of any regulatory protein, and identified an in-built novel regulatory mechanism engaging its C-terminal region.
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Affiliation(s)
- Prabha Verma
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Poonam Kumari
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Shreya Negi
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Gitanjali Yadav
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Vineet Gaur
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India
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6
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Hallinan JP, Doyle LA, Shen BW, Gewe MM, Takushi B, Kennedy MA, Friend D, Roberts JM, Bradley P, Stoddard BL. Design of functionalised circular tandem repeat proteins with longer repeat topologies and enhanced subunit contact surfaces. Commun Biol 2021; 4:1240. [PMID: 34716407 PMCID: PMC8556268 DOI: 10.1038/s42003-021-02766-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 10/07/2021] [Indexed: 01/16/2023] Open
Abstract
Circular tandem repeat proteins (‘cTRPs’) are de novo designed protein scaffolds (in this and prior studies, based on antiparallel two-helix bundles) that contain repeated protein sequences and structural motifs and form closed circular structures. They can display significant stability and solubility, a wide range of sizes, and are useful as protein display particles for biotechnology applications. However, cTRPs also demonstrate inefficient self-assembly from smaller subunits. In this study, we describe a new generation of cTRPs, with longer repeats and increased interaction surfaces, which enhanced the self-assembly of two significantly different sizes of homotrimeric constructs. Finally, we demonstrated functionalization of these constructs with (1) a hexameric array of peptide-binding SH2 domains, and (2) a trimeric array of anti-SARS CoV-2 VHH domains. The latter proved capable of sub-nanomolar binding affinities towards the viral receptor binding domain and potent viral neutralization function. Jazmine Hallinan et al. report the development of a new generation of circular tandem repeat proteins with enhanced self-assembly. Functionalisation of these constructs with SARS CoV-2 VHH domains resulted in sub-nanomolar binding affinity to the viral receptor binding domain.
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Affiliation(s)
- Jazmine P Hallinan
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. North, Seattle, WA, 98109, USA
| | - Lindsey A Doyle
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. North, Seattle, WA, 98109, USA
| | - Betty W Shen
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. North, Seattle, WA, 98109, USA
| | - Mesfin M Gewe
- Lumen Bioscience Inc., 1441 North 34th Street, Seattle, WA, 98103, USA
| | - Brittany Takushi
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. North, Seattle, WA, 98109, USA
| | - Madison A Kennedy
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. North, Seattle, WA, 98109, USA
| | - Della Friend
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. North, Seattle, WA, 98109, USA
| | - James M Roberts
- Lumen Bioscience Inc., 1441 North 34th Street, Seattle, WA, 98103, USA
| | - Philip Bradley
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. North, Seattle, WA, 98109, USA. .,Division of Public Health Sciences and Program in Computational Biology, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N., Seattle, WA, 98009, USA.
| | - Barry L Stoddard
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. North, Seattle, WA, 98109, USA.
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7
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Xu X, Wang M, Sun J, Yu Z, Li G, Yang N, Xu RM. Structure specific DNA recognition by the SLX1-SLX4 endonuclease complex. Nucleic Acids Res 2021; 49:7740-7752. [PMID: 34181713 PMCID: PMC8287910 DOI: 10.1093/nar/gkab542] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Revised: 06/04/2021] [Accepted: 06/11/2021] [Indexed: 11/13/2022] Open
Abstract
The SLX1–SLX4 structure-specific endonuclease complex is involved in processing diverse DNA damage intermediates, including resolution of Holliday junctions, collapse of stalled replication forks and removal of DNA flaps. The nuclease subunit SLX1 is inactive on its own, but become activated upon binding to SLX4 via its conserved C-terminal domain (CCD). Yet, how the SLX1–SLX4 complex recognizes specific DNA structure and chooses cleavage sites remains unknown. Here we show, through a combination of structural, biochemical and computational analyses, that the SAP domain of SLX4 is critical for efficient and accurate processing of 5′-flap DNA. It binds the minor groove of DNA about one turn away from the flap junction, and the 5′-flap is implicated in binding the core domain of SLX1. This binding mode accounts for specific recognition of 5′-flap DNA and specification of cleavage site by the SLX1–SLX4 complex.
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Affiliation(s)
- Xiang Xu
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy and Key Laboratory of Medical Data Analysis and Statistical Research of Tianjin, Nankai University, Tianjin 300353, China.,National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Mingzhu Wang
- Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, Anhui, China
| | - Jixue Sun
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy and Key Laboratory of Medical Data Analysis and Statistical Research of Tianjin, Nankai University, Tianjin 300353, China
| | - Zhenyu Yu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Guohong Li
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.,School of Life Science, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Na Yang
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy and Key Laboratory of Medical Data Analysis and Statistical Research of Tianjin, Nankai University, Tianjin 300353, China
| | - Rui-Ming Xu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.,School of Life Science, University of Chinese Academy of Sciences, Beijing 100049, China
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8
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Song J, Freeman AD, Knebel A, Gartner A, Lilley DM. Human ANKLE1 Is a Nuclease Specific for Branched DNA. J Mol Biol 2020; 432:5825-5834. [PMID: 32866453 PMCID: PMC7610144 DOI: 10.1016/j.jmb.2020.08.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 08/24/2020] [Accepted: 08/24/2020] [Indexed: 12/02/2022]
Abstract
All physical connections between sister chromatids must be broken before cells can divide, and eukaryotic cells have evolved multiple ways in which to process branchpoints connecting DNA molecules separated both spatially and temporally. A single DNA link between chromatids has the potential to disrupt cell cycle progression and genome integrity, so it is highly likely that cells require a nuclease that can process remaining unresolved and hemi-resolved DNA junctions and other branched species at the very late stages of mitosis. We argue that ANKLE1 probably serves this function in human cells (LEM-3 in Caenorhabditis elegans). LEM-3 has previously been shown to be located at the cell mid-body, and we show here that human ANKLE1 is a nuclease that cleaves a range of branched DNA species. It thus has the substrate selectivity consistent with an enzyme required to process a variety of unresolved and hemi-resolved branchpoints in DNA. Our results suggest that ANKLE1 acts as a catch-all enzyme of last resort that allows faithful chromosome segregation and cell division to occur.
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Affiliation(s)
- Junfang Song
- Cancer Research UK Nucleic Acid Structure Research Group, MSI/WTB Complex, University of Dundee, Dow Street, Dundee DD1 5EH, UK
- Centre for Gene Regulation and Expression, University of Dundee, Dundee DD1 5EH, UK
| | - Alasdair D.J. Freeman
- Cancer Research UK Nucleic Acid Structure Research Group, MSI/WTB Complex, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Axel Knebel
- MRC Protein Phosphorylation Unit, University of Dundee, Dundee DD1 5EH, UK
| | - Anton Gartner
- Centre for Gene Regulation and Expression, University of Dundee, Dundee DD1 5EH, UK
- Department of Biological Sciences, School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, Republic of Korea
| | - David M.J. Lilley
- Cancer Research UK Nucleic Acid Structure Research Group, MSI/WTB Complex, University of Dundee, Dow Street, Dundee DD1 5EH, UK
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9
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Gaur V, Ziajko W, Nirwal S, Szlachcic A, Gapińska M, Nowotny M. Recognition and processing of branched DNA substrates by Slx1-Slx4 nuclease. Nucleic Acids Res 2019; 47:11681-11690. [PMID: 31584081 PMCID: PMC6902002 DOI: 10.1093/nar/gkz842] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 09/16/2019] [Accepted: 10/01/2019] [Indexed: 12/11/2022] Open
Abstract
Structure-selective endonucleases cleave branched DNA substrates. Slx1 is unique among structure-selective nucleases because it can cleave all branched DNA structures at multiple sites near the branch point. The mechanism behind this broad range of activity is unknown. The present study structurally and biochemically investigated fungal Slx1 to define a new protein interface that binds the non-cleaved arm of branched DNAs. The DNA arm bound at this new site was positioned at a sharp angle relative to the arm that was modeled to interact with the active site, implying that Slx1 uses DNA bending to localize the branch point as a flexible discontinuity in DNA. DNA binding at the new interface promoted a disorder-order transition in a region of the protein that was located in the vicinity of the active site, potentially participating in its formation. This appears to be a safety mechanism that ensures that DNA cleavage occurs only when the new interface is occupied by the non-cleaved DNA arm. Models of Slx1 that interacted with various branched DNA substrates were prepared. These models explain the way in which Slx1 cuts DNA toward the 3' end away from the branch point and elucidate the unique ability of Slx1 to cleave various DNA structures.
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Affiliation(s)
- Vineet Gaur
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Trojdena St., 02-109 Warsaw, Poland
| | - Weronika Ziajko
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Trojdena St., 02-109 Warsaw, Poland
| | - Shivlee Nirwal
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Trojdena St., 02-109 Warsaw, Poland
| | - Aleksandra Szlachcic
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Trojdena St., 02-109 Warsaw, Poland
| | - Marta Gapińska
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Trojdena St., 02-109 Warsaw, Poland
| | - Marcin Nowotny
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Trojdena St., 02-109 Warsaw, Poland
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10
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Harrison RL, Mowery JD, Bauchan GR, Theilmann DA, Erlandson MA. The complete genome sequence of a second alphabaculovirus from the true armyworm, Mythimna unipuncta: implications for baculovirus phylogeny and host specificity. Virus Genes 2018; 55:104-116. [PMID: 30430308 DOI: 10.1007/s11262-018-1615-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 11/09/2018] [Indexed: 12/19/2022]
Abstract
The Mythimna unipuncta nucleopolyhedrovirus isolate KY310 (MyunNPV-KY310) is an alphabaculovirus isolated from a true armyworm (Mythimna unipuncta) population in Kentucky, USA. Occlusion bodies of this virus were examined by electron microscopy and the genome sequence was determined by 454 pyrosequencing. MyunNPV-KY310 occlusion bodies consisted of irregular polyhedra measuring 0.8-1.8 µm in diameter and containing multiple virions, with one to six nucleocapsids per virion. The genome sequence was determined to be 156,647 bp with a nucleotide distribution of 43.9% G+C. 152 ORFs and six homologous repeat (hr) regions were annotated for the sequence, including the 38 core genes of family Baculoviridae and an additional group of 26 conserved alphabaculovirus genes. BLAST queries and phylogenetic inference confirmed that MyunNPV-KY310 is most closely related to the alphabaculovirus Leucania separata nucleopolyhedrovirus isolate AH1, which infects Mythimna separata. In contrast, MyunNPV-KY310 did not exhibit a close relationship with Mythimna unipuncta nucleopolyhedrovirus isolate #7, an alphabaculovirus from the same host species. MyunNPV-KY310 lacks the gp64 envelope glycoprotein, which is a characteristic of group II alphabaculoviruses. However, this virus and five other alphabaculoviruses lacking gp64 are placed outside the group I and group II clades in core gene phylogenies, further demonstrating that viruses of genus Alphabaculovirus do not occur in two monophyletic clades. Potential instances of MyunNPV-KY310 ORFs arising by horizontal transfer were detected. Although there are now genome sequences of four different baculoviruses from M. unipuncta, comparison of their genome sequences provides little insight into the genetic basis for their host specificity.
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Affiliation(s)
- Robert L Harrison
- Invasive Insect Biocontrol and Behavior Laboratory, Beltsville Agricultural Research Center, USDA Agricultural Research Service, Beltsville, MD, 20705, USA.
| | - Joseph D Mowery
- Electron and Confocal Microscopy Unit, Beltsville Agricultural Research Center, USDA Agricultural Research Service, Beltsville, MD, 20705, USA
| | - Gary R Bauchan
- Electron and Confocal Microscopy Unit, Beltsville Agricultural Research Center, USDA Agricultural Research Service, Beltsville, MD, 20705, USA
| | - David A Theilmann
- Summerland Research and Development Centre, Agriculture and Agri-Food Canada, Summerland, BC, V0H 1Z0, Canada
| | - Martin A Erlandson
- Saskatoon Research and Development Centre, Agriculture and Agri-Food Canada, Saskatoon, SK, S7N 0X2, Canada
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11
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Genomic and ecological study of two distinctive freshwater bacteriophages infecting a Comamonadaceae bacterium. Sci Rep 2018; 8:7989. [PMID: 29789681 PMCID: PMC5964084 DOI: 10.1038/s41598-018-26363-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 05/10/2018] [Indexed: 01/29/2023] Open
Abstract
Bacteriophages of freshwater environments have not been well studied despite their numerical dominance and ecological importance. Currently, very few phages have been isolated for many abundant freshwater bacterial groups, especially for the family Comamonadaceae that is found ubiquitously in freshwater habitats. In this study, we report two novel phages, P26059A and P26059B, that were isolated from Lake Soyang in South Korea, and lytically infected bacterial strain IMCC26059, a member of the family Comamonadaceae. Morphological observations revealed that phages P26059A and P26059B belonged to the family Siphoviridae and Podoviridae, respectively. Of 12 bacterial strains tested, the two phages infected strain IMCC26059 only, showing a very narrow host range. The genomes of the two phages were different in length and highly distinct from each other with little sequence similarity. A comparison of the phage genome sequences and freshwater viral metagenomes showed that the phage populations represented by P26059A and P26059B exist in the environment with different distribution patterns. Presence of the phages in Lake Soyang and Lake Michigan also indicated a consistent lytic infection of the Comamonadaceae bacterium, which might control the population size of this bacterial group. Taken together, although the two phages shared a host strain, they showed completely distinctive characteristics from each other in morphological, genomic, and ecological analyses. Considering the abundance of the family Comamonadaceae in freshwater habitats and the rarity of phage isolates infecting this family, the two phages and their genomes in this study would be valuable resources for freshwater virus research.
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12
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Liu Y, Freeman A, Déclais AC, Gartner A, Lilley DMJ. Biochemical and Structural Properties of Fungal Holliday Junction-Resolving Enzymes. Methods Enzymol 2018; 600:543-568. [PMID: 29458774 DOI: 10.1016/bs.mie.2017.11.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Four-way Holliday junctions in DNA are the central intermediates of genetic recombination and must be processed into regular duplex species. One mechanism for achieving this is called resolution, brought about by structure-selective nucleases. GEN1 is an important junction-resolving enzyme in eukaryotic cells, a member of the FEN1/EXO1 superfamily of nucleases. While human GEN1 is difficult to work with because of aggregation, orthologs from thermophilic fungi have been identified using bioinformatics and have proved to have excellent properties. Here, the expression and purification of this enzyme from Chaetomium thermophilum is described, together with the means of investigating its biochemical properties. The enzyme is quite similar to junction-resolving enzymes from lower organisms, binding to junctions in dimeric form, introducing symmetrical bilateral cleavages, the second of which is accelerated to promote productive resolution. Crystallization of C. thermophilum GEN1 is described, and the structure of a DNA-product complex. Juxtaposition of complexes in the crystal lattice suggests how the structure of a dimeric enzyme with an intact junction is organized.
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Affiliation(s)
- Yijin Liu
- Cancer Research UK Nucleic Acid Structure Research Group, The University of Dundee, Dundee, United Kingdom
| | - Alasdair Freeman
- Cancer Research UK Nucleic Acid Structure Research Group, The University of Dundee, Dundee, United Kingdom
| | - Anne-Cécile Déclais
- Cancer Research UK Nucleic Acid Structure Research Group, The University of Dundee, Dundee, United Kingdom
| | - Anton Gartner
- Cancer Research UK Nucleic Acid Structure Research Group, The University of Dundee, Dundee, United Kingdom
| | - David M J Lilley
- Cancer Research UK Nucleic Acid Structure Research Group, The University of Dundee, Dundee, United Kingdom.
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13
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Lilley DMJ. Holliday junction-resolving enzymes-structures and mechanisms. FEBS Lett 2017; 591:1073-1082. [PMID: 27990631 DOI: 10.1002/1873-3468.12529] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Revised: 12/12/2016] [Accepted: 12/13/2016] [Indexed: 12/15/2022]
Abstract
Holliday junction-resolving enzymes are nucleases that are highly specific for the structure of the junction, to which they bind in dimeric form. Two symmetrically disposed cleavages are made. These are not simultaneous, but the second cleavage is accelerated relative to the first, so ensuring that bilateral cleavage occurs during the lifetime of the DNA-protein complex. In eukaryotic cells there are two known junction-resolving activities. GEN1 is similar to enzymes from lower organisms. A crystallographic structure of a fungal GEN1 bound to the product of resolution has been determined. These complexes are dimerized within the crystal lattice such that the strands of the products may be simply reconnected to form a junction. These structures suggest a trajectory for the resolution process.
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Affiliation(s)
- David M J Lilley
- Cancer Research UK Nucleic Acid Structure Research Group, The University of Dundee, UK
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14
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Roy AC, Wilson GG, Edgell DR. Perpetuating the homing endonuclease life cycle: identification of mutations that modulate and change I-TevI cleavage preference. Nucleic Acids Res 2016; 44:7350-9. [PMID: 27387281 PMCID: PMC5009752 DOI: 10.1093/nar/gkw614] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 06/27/2016] [Indexed: 11/14/2022] Open
Abstract
Homing endonucleases are sequence-tolerant DNA endonucleases that act as mobile genetic elements. The ability of homing endonucleases to cleave substrates with multiple nucleotide substitutions suggests a high degree of adaptability in that changing or modulating cleavage preference would require relatively few amino acid substitutions. Here, using directed evolution experiments with the GIY-YIG homing endonuclease I-TevI that targets the thymidylate synthase gene of phage T4, we readily isolated variants that dramatically broadened I-TevI cleavage preference, as well as variants that fine-tuned cleavage preference. By combining substitutions, we observed an ∼10 000-fold improvement in cleavage on some substrates not cleaved by the wild-type enzyme, correlating with a decrease in readout of information content at the cleavage site. Strikingly, we were able to change the cleavage preference of I-TevI to that of the isoschizomer I-BmoI which targets a different cleavage site in the thymidylate synthase gene, recapitulating the evolution of cleavage preference in this family of homing endonucleases. Our results define a strategy to isolate GIY-YIG nuclease domains with distinct cleavage preferences, and provide insight into how homing endonucleases may escape a dead-end life cycle in a population of saturated target sites by promoting transposition to different target sites.
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Affiliation(s)
- Alexander C Roy
- Department of Biochemistry, Schulich School of Medicine and Dentistry, Western University, London, ON, N6A 5C1, Canada
| | | | - David R Edgell
- Department of Biochemistry, Schulich School of Medicine and Dentistry, Western University, London, ON, N6A 5C1, Canada
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15
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Lambert AR, Hallinan JP, Shen BW, Chik JK, Bolduc JM, Kulshina N, Robins LI, Kaiser BK, Jarjour J, Havens K, Scharenberg AM, Stoddard BL. Indirect DNA Sequence Recognition and Its Impact on Nuclease Cleavage Activity. Structure 2016; 24:862-73. [PMID: 27133026 DOI: 10.1016/j.str.2016.03.024] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 03/07/2016] [Accepted: 03/21/2016] [Indexed: 11/29/2022]
Abstract
LAGLIDADG meganucleases are DNA cleaving enzymes used for genome engineering. While their cleavage specificity can be altered using several protein engineering and selection strategies, their overall targetability is limited by highly specific indirect recognition of the central four base pairs within their recognition sites. In order to examine the physical basis of indirect sequence recognition and to expand the number of such nucleases available for genome engineering, we have determined the target sites, DNA-bound structures, and central four cleavage fidelities of nine related enzymes. Subsequent crystallographic analyses of a meganuclease bound to two noncleavable target sites, each containing a single inactivating base pair substitution at its center, indicates that a localized slip of the mutated base pair causes a small change in the DNA backbone conformation that results in a loss of metal occupancy at one binding site, eliminating cleavage activity.
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Affiliation(s)
- Abigail R Lambert
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, A3-025, Seattle, WA 98109, USA
| | - Jazmine P Hallinan
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, A3-025, Seattle, WA 98109, USA
| | - Betty W Shen
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, A3-025, Seattle, WA 98109, USA
| | - Jennifer K Chik
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, A3-025, Seattle, WA 98109, USA
| | - Jill M Bolduc
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, A3-025, Seattle, WA 98109, USA
| | - Nadia Kulshina
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, A3-025, Seattle, WA 98109, USA
| | - Lori I Robins
- Physical Sciences Division, School of STEM, University of Washington, 18115 Campus Way Northeast, Bothell, WA 98011, USA
| | - Brett K Kaiser
- Department of Biology, Seattle University, 901 12th Avenue, Seattle, WA 98122, USA
| | - Jordan Jarjour
- bluebird bio Inc. Suite 207, 1616 Eastlake Avenue East, Seattle, WA 98102, USA
| | - Kyle Havens
- bluebird bio Inc. Suite 207, 1616 Eastlake Avenue East, Seattle, WA 98102, USA
| | - Andrew M Scharenberg
- Seattle Children's Research Institute, 1900 Ninth Avenue, Seattle, WA 98101, USA
| | - Barry L Stoddard
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, A3-025, Seattle, WA 98109, USA.
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16
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Nowotny M, Gaur V. Structure and mechanism of nucleases regulated by SLX4. Curr Opin Struct Biol 2016; 36:97-105. [PMID: 26827285 DOI: 10.1016/j.sbi.2016.01.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 01/06/2016] [Accepted: 01/07/2016] [Indexed: 01/08/2023]
Abstract
SLX4 is a multidomain platform that regulates various proteins that are involved in genome maintenance and stability. Among these proteins are three structure-selective nucleases (SSEs). XPF-ERCC1 and MUS81-EME1 are structurally similar and function as heterodimers of highly similar subunits, in which only one is active. Two independent modules are formed from subunits of the heterodimers - a dimer of nuclease and nuclease-like domains and a dimer of tandem helix-hairpin-helix HhH2 domains. Both modules are responsible for substrate recognition. The third SSE, SLX1, contains GIY-YIG and RING domains and is a promiscuous nuclease. Structural data imply that SLX1 exists in free form as an autoinhibited homodimer. Association with SLX4 platform disrupts the homodimer and activates SLX1. This review discusses the available structural and mechanistic information on SLX4-regulated SSEs.
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Affiliation(s)
- Marcin Nowotny
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, Warsaw, Poland.
| | - Vineet Gaur
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, Warsaw, Poland.
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17
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Doyle L, Hallinan J, Bolduc J, Parmeggiani F, Baker D, Stoddard BL, Bradley P. Rational design of α-helical tandem repeat proteins with closed architectures. Nature 2015; 528:585-8. [PMID: 26675735 PMCID: PMC4727831 DOI: 10.1038/nature16191] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 10/30/2015] [Indexed: 12/02/2022]
Abstract
Tandem repeat proteins, which are formed by repetition of modular units of protein sequence and structure, play important biological roles as macromolecular binding and scaffolding domains, enzymes, and building blocks for the assembly of fibrous materials1,2. The modular nature of repeat proteins enables the rapid construction and diversification of extended binding surfaces by duplication and recombination of simple building blocks3,4. The overall architecture of tandem repeat protein structures – which is dictated by the internal geometry and local packing of the repeat building blocks – is highly diverse, ranging from extended, super-helical folds that bind peptide, DNA, and RNA partners5–9, to closed and compact conformations with internal cavities suitable for small molecule binding and catalysis10. Here we report the development and validation of computational methods for de novo design of tandem repeat protein architectures driven purely by geometric criteria defining the inter-repeat geometry, without reference to the sequences and structures of existing repeat protein families. We have applied these methods to design a series of closed alpha-solenoid11 repeat structures (alpha-toroids) in which the inter-repeat packing geometry is constrained so as to juxtapose the N- and C-termini; several of these designed structures have been validated by X-ray crystallography. Unlike previous approaches to tandem repeat protein engineering12–20, our design procedure does not rely on template sequence or structural information taken from natural repeat proteins and hence can produce structures unlike those seen in nature. As an example, we have successfully designed and validated closed alpha-solenoid repeats with a left-handed helical architecture that – to our knowledge – is not yet present in the protein structure database21.
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Affiliation(s)
- Lindsey Doyle
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N., Seattle, Washington 98109, USA
| | - Jazmine Hallinan
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N., Seattle, Washington 98109, USA
| | - Jill Bolduc
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N., Seattle, Washington 98109, USA
| | - Fabio Parmeggiani
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA.,Institute for Protein Design, University of Washington, Seattle, Washington 98195, USA
| | - David Baker
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA.,Institute for Protein Design, University of Washington, Seattle, Washington 98195, USA.,Howard Hughes Medical Institute, University of Washington, Seattle, Washington 98195, USA
| | - Barry L Stoddard
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N., Seattle, Washington 98109, USA
| | - Philip Bradley
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N., Seattle, Washington 98109, USA.,Institute for Protein Design, University of Washington, Seattle, Washington 98195, USA.,Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N., Seattle, Washington 98019, USA
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18
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Tanas AS, Kuznetsova EB, Borisova ME, Rudenko VV, Zaletayev DV, Strelnikov VV. Reduced representation bisulfite sequencing design for assessing the methylation of human CpG islands in large samples. Mol Biol 2015. [DOI: 10.1134/s0026893315040184] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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19
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Gaur V, Wyatt HDM, Komorowska W, Szczepanowski RH, de Sanctis D, Gorecka KM, West SC, Nowotny M. Structural and Mechanistic Analysis of the Slx1-Slx4 Endonuclease. Cell Rep 2015; 10:1467-1476. [PMID: 25753413 PMCID: PMC4407285 DOI: 10.1016/j.celrep.2015.02.019] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 01/16/2015] [Accepted: 02/03/2015] [Indexed: 11/24/2022] Open
Abstract
The SLX1-SLX4 endonuclease required for homologous recombination and DNA repair in eukaryotic cells cleaves a variety of branched DNA structures. The nuclease subunit SLX1 is activated by association with a scaffolding protein SLX4. At the present time, little is known about the structure of SLX1-SLX4 or its mechanism of action. Here, we report the structural insights into SLX1-SLX4 by detailing the crystal structure of Candida glabrata (Cg) Slx1 alone and in combination with the C-terminal region of Slx4. The structure of Slx1 reveals a compact arrangement of the GIY-YIG nuclease and RING domains, which is reinforced by a long α helix. Slx1 forms a stable homodimer that blocks its active site. Slx1-Slx4 interaction is mutually exclusive with Slx1 homodimerization, suggesting a mechanism for Slx1 activation by Slx4.
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Affiliation(s)
- Vineet Gaur
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Księcia Trojdena Street, 02-109 Warsaw, Poland
| | - Haley D M Wyatt
- London Research Institute, Cancer Research UK, Clare Hall Laboratories, Blanche Lane, South Mimms, Herts EN6 3LD, UK
| | - Weronika Komorowska
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Księcia Trojdena Street, 02-109 Warsaw, Poland
| | - Roman H Szczepanowski
- Biophysics Core Facility, International Institute of Molecular and Cell Biology, 4 Księcia Trojdena Street, 02-109 Warsaw, Poland
| | - Daniele de Sanctis
- European Synchrotron Radiation Facility (ESRF), 71 Avenue des Martyrs, CS 40220, 38043 Grenoble Cédex 9, France
| | - Karolina M Gorecka
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Księcia Trojdena Street, 02-109 Warsaw, Poland
| | - Stephen C West
- London Research Institute, Cancer Research UK, Clare Hall Laboratories, Blanche Lane, South Mimms, Herts EN6 3LD, UK
| | - Marcin Nowotny
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Księcia Trojdena Street, 02-109 Warsaw, Poland.
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20
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Freeman ADJ, Liu Y, Déclais AC, Gartner A, Lilley DMJ. GEN1 from a thermophilic fungus is functionally closely similar to non-eukaryotic junction-resolving enzymes. J Mol Biol 2014; 426:3946-3959. [PMID: 25315822 PMCID: PMC4270448 DOI: 10.1016/j.jmb.2014.10.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 10/06/2014] [Accepted: 10/07/2014] [Indexed: 11/28/2022]
Abstract
Processing of Holliday junctions is essential in recombination. We have identified the gene for the junction-resolving enzyme GEN1 from the thermophilic fungus Chaetomium thermophilum and expressed the N-terminal 487-amino-acid section. The protein is a nuclease that is highly selective for four-way DNA junctions, cleaving 1nt 3' to the point of strand exchange on two strands symmetrically disposed about a diagonal axis. CtGEN1 binds to DNA junctions as a discrete homodimer with nanomolar affinity. Analysis of the kinetics of cruciform cleavage shows that cleavage of the second strand occurs an order of magnitude faster than the first cleavage so as to generate a productive resolution event. All these properties are closely similar to those described for bacterial, phage and mitochondrial junction-resolving enzymes. CtGEN1 is also similar in properties to the human enzyme but lacks the problems with aggregation that currently prevent detailed analysis of the latter protein. CtGEN1 is thus an excellent enzyme with which to engage in biophysical and structural analysis of eukaryotic GEN1.
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Affiliation(s)
- Alasdair D J Freeman
- Cancer Research UK Nucleic Acid Structure Research Group, MSI/WTB Complex, The University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Yijin Liu
- Cancer Research UK Nucleic Acid Structure Research Group, MSI/WTB Complex, The University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Anne-Cécile Déclais
- Cancer Research UK Nucleic Acid Structure Research Group, MSI/WTB Complex, The University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Anton Gartner
- Cancer Research UK Nucleic Acid Structure Research Group, MSI/WTB Complex, The University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - David M J Lilley
- Cancer Research UK Nucleic Acid Structure Research Group, MSI/WTB Complex, The University of Dundee, Dow Street, Dundee DD1 5EH, UK.
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21
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Pingoud A, Wilson GG, Wende W. Type II restriction endonucleases--a historical perspective and more. Nucleic Acids Res 2014; 42:7489-527. [PMID: 24878924 PMCID: PMC4081073 DOI: 10.1093/nar/gku447] [Citation(s) in RCA: 169] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 05/02/2014] [Accepted: 05/07/2014] [Indexed: 12/17/2022] Open
Abstract
This article continues the series of Surveys and Summaries on restriction endonucleases (REases) begun this year in Nucleic Acids Research. Here we discuss 'Type II' REases, the kind used for DNA analysis and cloning. We focus on their biochemistry: what they are, what they do, and how they do it. Type II REases are produced by prokaryotes to combat bacteriophages. With extreme accuracy, each recognizes a particular sequence in double-stranded DNA and cleaves at a fixed position within or nearby. The discoveries of these enzymes in the 1970s, and of the uses to which they could be put, have since impacted every corner of the life sciences. They became the enabling tools of molecular biology, genetics and biotechnology, and made analysis at the most fundamental levels routine. Hundreds of different REases have been discovered and are available commercially. Their genes have been cloned, sequenced and overexpressed. Most have been characterized to some extent, but few have been studied in depth. Here, we describe the original discoveries in this field, and the properties of the first Type II REases investigated. We discuss the mechanisms of sequence recognition and catalysis, and the varied oligomeric modes in which Type II REases act. We describe the surprising heterogeneity revealed by comparisons of their sequences and structures.
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Affiliation(s)
- Alfred Pingoud
- Institute of Biochemistry, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany
| | - Geoffrey G Wilson
- New England Biolabs Inc., 240 County Road, Ipswich, MA 01938-2723, USA
| | - Wolfgang Wende
- Institute of Biochemistry, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany
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22
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Horton JR, Borgaro JG, Griggs RM, Quimby A, Guan S, Zhang X, Wilson GG, Zheng Y, Zhu Z, Cheng X. Structure of 5-hydroxymethylcytosine-specific restriction enzyme, AbaSI, in complex with DNA. Nucleic Acids Res 2014; 42:7947-59. [PMID: 24895434 PMCID: PMC4081097 DOI: 10.1093/nar/gku497] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AbaSI, a member of the PvuRts1I-family of modification-dependent restriction endonucleases, cleaves deoxyribonucleic acid (DNA) containing 5-hydroxymethylctosine (5hmC) and glucosylated 5hmC (g5hmC), but not DNA containing unmodified cytosine. AbaSI has been used as a tool for mapping the genomic locations of 5hmC, an important epigenetic modification in the DNA of higher organisms. Here we report the crystal structures of AbaSI in the presence and absence of DNA. These structures provide considerable, although incomplete, insight into how this enzyme acts. AbaSI appears to be mainly a homodimer in solution, but interacts with DNA in our structures as a homotetramer. Each AbaSI subunit comprises an N-terminal, Vsr-like, cleavage domain containing a single catalytic site, and a C-terminal, SRA-like, 5hmC-binding domain. Two N-terminal helices mediate most of the homodimer interface. Dimerization brings together the two catalytic sites required for double-strand cleavage, and separates the 5hmC binding-domains by ∼70 Å, consistent with the known activity of AbaSI which cleaves DNA optimally between symmetrically modified cytosines ∼22 bp apart. The eukaryotic SET and RING-associated (SRA) domains bind to DNA containing 5-methylcytosine (5mC) in the hemi-methylated CpG sequence. They make contacts in both the major and minor DNA grooves, and flip the modified cytosine out of the helix into a conserved binding pocket. In contrast, the SRA-like domain of AbaSI, which has no sequence specificity, contacts only the minor DNA groove, and in our current structures the 5hmC remains intra-helical. A conserved, binding pocket is nevertheless present in this domain, suitable for accommodating 5hmC and g5hmC. We consider it likely, therefore, that base-flipping is part of the recognition and cleavage mechanism of AbaSI, but that our structures represent an earlier, pre-flipped stage, prior to actual recognition.
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Affiliation(s)
- John R Horton
- Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road, Atlanta, Georgia 30322, USA
| | - Janine G Borgaro
- New England Biolabs, Inc., 240 County Road, Ipswich, MA 01938, USA
| | - Rose M Griggs
- Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road, Atlanta, Georgia 30322, USA
| | - Aine Quimby
- New England Biolabs, Inc., 240 County Road, Ipswich, MA 01938, USA
| | - Shengxi Guan
- New England Biolabs, Inc., 240 County Road, Ipswich, MA 01938, USA
| | - Xing Zhang
- Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road, Atlanta, Georgia 30322, USA
| | | | - Yu Zheng
- New England Biolabs, Inc., 240 County Road, Ipswich, MA 01938, USA
| | - Zhenyu Zhu
- New England Biolabs, Inc., 240 County Road, Ipswich, MA 01938, USA
| | - Xiaodong Cheng
- Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road, Atlanta, Georgia 30322, USA
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23
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Abstract
Homing endonucleases are strong drivers of genetic exchange and horizontal transfer of both their own genes and their local genetic environment. The mechanisms that govern the function and evolution of these genetic oddities have been well documented over the past few decades at the genetic, biochemical, and structural levels. This wealth of information has led to the manipulation and reprogramming of the endonucleases and to their exploitation in genome editing for use as therapeutic agents, for insect vector control and in agriculture. In this chapter we summarize the molecular properties of homing endonucleases and discuss their strengths and weaknesses in genome editing as compared to other site-specific nucleases such as zinc finger endonucleases, TALEN, and CRISPR-derived endonucleases.
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Loenen WAM, Dryden DTF, Raleigh EA, Wilson GG, Murray NE. Highlights of the DNA cutters: a short history of the restriction enzymes. Nucleic Acids Res 2014; 42:3-19. [PMID: 24141096 PMCID: PMC3874209 DOI: 10.1093/nar/gkt990] [Citation(s) in RCA: 195] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 09/24/2013] [Accepted: 10/02/2013] [Indexed: 11/16/2022] Open
Abstract
In the early 1950's, 'host-controlled variation in bacterial viruses' was reported as a non-hereditary phenomenon: one cycle of viral growth on certain bacterial hosts affected the ability of progeny virus to grow on other hosts by either restricting or enlarging their host range. Unlike mutation, this change was reversible, and one cycle of growth in the previous host returned the virus to its original form. These simple observations heralded the discovery of the endonuclease and methyltransferase activities of what are now termed Type I, II, III and IV DNA restriction-modification systems. The Type II restriction enzymes (e.g. EcoRI) gave rise to recombinant DNA technology that has transformed molecular biology and medicine. This review traces the discovery of restriction enzymes and their continuing impact on molecular biology and medicine.
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Affiliation(s)
- Wil A. M. Loenen
- Leiden University Medical Center, Leiden, the Netherlands, EaStChemSchool of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, Scotland, UK and New England Biolabs, Inc., 240 County Road, Ipswich, MA 01938, USA
| | - David T. F. Dryden
- Leiden University Medical Center, Leiden, the Netherlands, EaStChemSchool of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, Scotland, UK and New England Biolabs, Inc., 240 County Road, Ipswich, MA 01938, USA
| | - Elisabeth A. Raleigh
- Leiden University Medical Center, Leiden, the Netherlands, EaStChemSchool of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, Scotland, UK and New England Biolabs, Inc., 240 County Road, Ipswich, MA 01938, USA
| | - Geoffrey G. Wilson
- Leiden University Medical Center, Leiden, the Netherlands, EaStChemSchool of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, Scotland, UK and New England Biolabs, Inc., 240 County Road, Ipswich, MA 01938, USA
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25
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Structural insights into the N-terminal GIY-YIG endonuclease activity of Arabidopsis glutaredoxin AtGRXS16 in chloroplasts. Proc Natl Acad Sci U S A 2013; 110:9565-70. [PMID: 23690600 DOI: 10.1073/pnas.1306899110] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Glutaredoxins (Grxs) have been identified across taxa as important mediators in various physiological functions. A chloroplastic monothiol glutaredoxin, AtGRXS16 from Arabidopsis thaliana, comprises two distinct functional domains, an N-terminal domain (NTD) with GlyIleTyr-TyrIleGly (GIY-YIG) endonuclease motif and a C-terminal Grx module, to coordinate redox regulation and DNA cleavage in chloroplasts. Structural determination of AtGRXS16-NTD showed that it possesses a GIY-YIG endonuclease fold, but the critical residues for the nuclease activity are different from typical GIY-YIG endonucleases. AtGRXS16-NTD was able to cleave λDNA and chloroplast genomic DNA, and the nuclease activity was significantly reduced in AtGRXS16. Functional analysis indicated that AtGRXS16-NTD could inhibit the ability of AtGRXS16 to suppress the sensitivity of yeast grx5 cells to oxidative stress; however, the C-terminal Grx domain itself and AtGRXS16 with a Cys123Ser mutation were active in these cells and able to functionally complement a Grx5 deficiency in yeast. Furthermore, the two functional domains were shown to be negatively regulated through the formation of an intramolecular disulfide bond. These findings unravel a manner of regulation for Grxs and provide insights into the mechanistic link between redox regulation and DNA metabolism in chloroplasts.
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26
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Kleinstiver BP, Wolfs JM, Edgell DR. The monomeric GIY-YIG homing endonuclease I-BmoI uses a molecular anchor and a flexible tether to sequentially nick DNA. Nucleic Acids Res 2013; 41:5413-27. [PMID: 23558745 PMCID: PMC3664794 DOI: 10.1093/nar/gkt186] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The GIY-YIG nuclease domain is found within protein scaffolds that participate in diverse cellular pathways and contains a single active site that hydrolyzes DNA by a one-metal ion mechanism. GIY-YIG homing endonucleases (GIY-HEs) are two-domain proteins with N-terminal GIY-YIG nuclease domains connected to C-terminal DNA-binding and they are thought to function as monomers. Using I-BmoI as a model GIY-HE, we test mechanisms by which the single active site is used to generate a double-strand break. We show that I-BmoI is partially disordered in the absence of substrate, and that the GIY-YIG domain alone has weak affinity for DNA. Significantly, we show that I-BmoI functions as a monomer at all steps of the reaction pathway and does not transiently dimerize or use sequential transesterification reactions to cleave substrate. Our results are consistent with the I-BmoI DNA-binding domain acting as a molecular anchor to tether the GIY-YIG domain to substrate, permitting rotation of the GIY-YIG domain to sequentially nick each DNA strand. These data highlight the mechanistic differences between monomeric GIY-HEs and dimeric or tetrameric GIY-YIG restriction enzymes, and they have implications for the use of the GIY-YIG domain in genome-editing applications.
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Affiliation(s)
- Benjamin P Kleinstiver
- Department of Biochemistry, Schulich School of Medicine and Dentistry, Western University, London, Ontario N6A 5C1, Canada
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27
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Aravind L, Anantharaman V, Zhang D, de Souza RF, Iyer LM. Gene flow and biological conflict systems in the origin and evolution of eukaryotes. Front Cell Infect Microbiol 2012; 2:89. [PMID: 22919680 PMCID: PMC3417536 DOI: 10.3389/fcimb.2012.00089] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Accepted: 06/13/2012] [Indexed: 11/24/2022] Open
Abstract
The endosymbiotic origin of eukaryotes brought together two disparate genomes in the cell. Additionally, eukaryotic natural history has included other endosymbiotic events, phagotrophic consumption of organisms, and intimate interactions with viruses and endoparasites. These phenomena facilitated large-scale lateral gene transfer and biological conflicts. We synthesize information from nearly two decades of genomics to illustrate how the interplay between lateral gene transfer and biological conflicts has impacted the emergence of new adaptations in eukaryotes. Using apicomplexans as example, we illustrate how lateral transfer from animals has contributed to unique parasite-host interfaces comprised of adhesion- and O-linked glycosylation-related domains. Adaptations, emerging due to intense selection for diversity in the molecular participants in organismal and genomic conflicts, being dispersed by lateral transfer, were subsequently exapted for eukaryote-specific innovations. We illustrate this using examples relating to eukaryotic chromatin, RNAi and RNA-processing systems, signaling pathways, apoptosis and immunity. We highlight the major contributions from catalytic domains of bacterial toxin systems to the origin of signaling enzymes (e.g., ADP-ribosylation and small molecule messenger synthesis), mutagenic enzymes for immune receptor diversification and RNA-processing. Similarly, we discuss contributions of bacterial antibiotic/siderophore synthesis systems and intra-genomic and intra-cellular selfish elements (e.g., restriction-modification, mobile elements and lysogenic phages) in the emergence of chromatin remodeling/modifying enzymes and RNA-based regulation. We develop the concept that biological conflict systems served as evolutionary “nurseries” for innovations in the protein world, which were delivered to eukaryotes via lateral gene flow to spur key evolutionary innovations all the way from nucleogenesis to lineage-specific adaptations.
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Affiliation(s)
- L Aravind
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda MD, USA.
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28
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Zhang D, de Souza RF, Anantharaman V, Iyer LM, Aravind L. Polymorphic toxin systems: Comprehensive characterization of trafficking modes, processing, mechanisms of action, immunity and ecology using comparative genomics. Biol Direct 2012; 7:18. [PMID: 22731697 PMCID: PMC3482391 DOI: 10.1186/1745-6150-7-18] [Citation(s) in RCA: 360] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Accepted: 05/31/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Proteinaceous toxins are observed across all levels of inter-organismal and intra-genomic conflicts. These include recently discovered prokaryotic polymorphic toxin systems implicated in intra-specific conflicts. They are characterized by a remarkable diversity of C-terminal toxin domains generated by recombination with standalone toxin-coding cassettes. Prior analysis revealed a striking diversity of nuclease and deaminase domains among the toxin modules. We systematically investigated polymorphic toxin systems using comparative genomics, sequence and structure analysis. RESULTS Polymorphic toxin systems are distributed across all major bacterial lineages and are delivered by at least eight distinct secretory systems. In addition to type-II, these include type-V, VI, VII (ESX), and the poorly characterized "Photorhabdus virulence cassettes (PVC)", PrsW-dependent and MuF phage-capsid-like systems. We present evidence that trafficking of these toxins is often accompanied by autoproteolytic processing catalyzed by HINT, ZU5, PrsW, caspase-like, papain-like, and a novel metallopeptidase associated with the PVC system. We identified over 150 distinct toxin domains in these systems. These span an extraordinary catalytic spectrum to include 23 distinct clades of peptidases, numerous previously unrecognized versions of nucleases and deaminases, ADP-ribosyltransferases, ADP ribosyl cyclases, RelA/SpoT-like nucleotidyltransferases, glycosyltranferases and other enzymes predicted to modify lipids and carbohydrates, and a pore-forming toxin domain. Several of these toxin domains are shared with host-directed effectors of pathogenic bacteria. Over 90 families of immunity proteins might neutralize anywhere between a single to at least 27 distinct types of toxin domains. In some organisms multiple tandem immunity genes or immunity protein domains are organized into polyimmunity loci or polyimmunity proteins. Gene-neighborhood-analysis of polymorphic toxin systems predicts the presence of novel trafficking-related components, and also the organizational logic that allows toxin diversification through recombination. Domain architecture and protein-length analysis revealed that these toxins might be deployed as secreted factors, through directed injection, or via inter-cellular contact facilitated by filamentous structures formed by RHS/YD, filamentous hemagglutinin and other repeats. Phyletic pattern and life-style analysis indicate that polymorphic toxins and polyimmunity loci participate in cooperative behavior and facultative 'cheating' in several ecosystems such as the human oral cavity and soil. Multiple domains from these systems have also been repeatedly transferred to eukaryotes and their viruses, such as the nucleo-cytoplasmic large DNA viruses. CONCLUSIONS Along with a comprehensive inventory of toxins and immunity proteins, we present several testable predictions regarding active sites and catalytic mechanisms of toxins, their processing and trafficking and their role in intra-specific and inter-specific interactions between bacteria. These systems provide insights regarding the emergence of key systems at different points in eukaryotic evolution, such as ADP ribosylation, interaction of myosin VI with cargo proteins, mediation of apoptosis, hyphal heteroincompatibility, hedgehog signaling, arthropod toxins, cell-cell interaction molecules like teneurins and different signaling messengers.
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Affiliation(s)
- Dapeng Zhang
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
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29
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Siwek W, Czapinska H, Bochtler M, Bujnicki JM, Skowronek K. Crystal structure and mechanism of action of the N6-methyladenine-dependent type IIM restriction endonuclease R.DpnI. Nucleic Acids Res 2012; 40:7563-72. [PMID: 22610857 PMCID: PMC3424567 DOI: 10.1093/nar/gks428] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
DNA methylation-dependent restriction enzymes have many applications in genetic engineering and in the analysis of the epigenetic state of eukaryotic genomes. Nevertheless, high-resolution structures have not yet been reported, and therefore mechanisms of DNA methylation-dependent cleavage are not understood. Here, we present a biochemical analysis and high-resolution DNA co-crystal structure of the N6-methyladenine (m6A)-dependent restriction enzyme R.DpnI. Our data show that R.DpnI consists of an N-terminal catalytic PD-(D/E)XK domain and a C-terminal winged helix (wH) domain. Surprisingly, both domains bind DNA in a sequence- and methylation-sensitive manner. The crystal contains R.DpnI with fully methylated target DNA bound to the wH domain, but distant from the catalytic domain. Independent readout of DNA sequence and methylation by the two domains might contribute to R.DpnI specificity or could help the monomeric enzyme to cut the second strand after introducing a nick.
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Affiliation(s)
- Wojciech Siwek
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology, Trojdena 4, 02-109 Warsaw, Poland
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30
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Abstract
Targeted manipulation of complex genomes often requires the introduction of a double-strand break at defined locations by site-specific DNA endonucleases. Here, we describe a monomeric nuclease domain derived from GIY-YIG homing endonucleases for genome-editing applications. Fusion of the GIY-YIG nuclease domain to three-member zinc-finger DNA binding domains generated chimeric GIY-zinc finger endonucleases (GIY-ZFEs). Significantly, the I-TevI-derived fusions (Tev-ZFEs) function in vitro as monomers to introduce a double-strand break, and discriminate in vitro and in bacterial and yeast assays against substrates lacking a preferred 5'-CNNNG-3' cleavage motif. The Tev-ZFEs function to induce recombination in a yeast-based assay with activity on par with a homodimeric Zif268 zinc-finger nuclease. We also fused the I-TevI nuclease domain to a catalytically inactive LADGLIDADG homing endonuclease (LHE) scaffold. The monomeric Tev-LHEs are active in vivo and similarly discriminate against substrates lacking the 5'-CNNNG-3' motif. The monomeric Tev-ZFEs and Tev-LHEs are distinct from the FokI-derived zinc-finger nuclease and TAL effector nuclease platforms as the GIY-YIG domain alleviates the requirement to design two nuclease fusions to target a given sequence, highlighting the diversity of nuclease domains with distinctive biochemical properties suitable for genome-editing applications.
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31
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Taylor GK, Stoddard BL. Structural, functional and evolutionary relationships between homing endonucleases and proteins from their host organisms. Nucleic Acids Res 2012; 40:5189-200. [PMID: 22406833 PMCID: PMC3384342 DOI: 10.1093/nar/gks226] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Homing endonucleases (HEs) are highly specific DNA-cleaving enzymes that are encoded by invasive DNA elements (usually mobile introns or inteins) within the genomes of phage, bacteria, archea, protista and eukaryotic organelles. Six unique structural HE families, that collectively span four distinct nuclease catalytic motifs, have been characterized to date. Members of each family display structural homology and functional relationships to a wide variety of proteins from various organisms. The biological functions of those proteins are highly disparate and include non-specific DNA-degradation enzymes, restriction endonucleases, DNA-repair enzymes, resolvases, intron splicing factors and transcription factors. These relationships suggest that modern day HEs share common ancestors with proteins involved in genome fidelity, maintenance and gene expression. This review summarizes the results of structural studies of HEs and corresponding proteins from host organisms that have illustrated the manner in which these factors are related.
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Affiliation(s)
- Gregory K Taylor
- Graduate Program in Molecular and Cellular Biology, University of Washington and Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N. A3-025, Seattle, WA 90109, USA
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32
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Mak ANS, Bradley P, Cernadas RA, Bogdanove AJ, Stoddard BL. The crystal structure of TAL effector PthXo1 bound to its DNA target. Science 2012; 335:716-9. [PMID: 22223736 DOI: 10.1126/science.1216211] [Citation(s) in RCA: 390] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
DNA recognition by TAL effectors is mediated by tandem repeats, each 33 to 35 residues in length, that specify nucleotides via unique repeat-variable diresidues (RVDs). The crystal structure of PthXo1 bound to its DNA target was determined by high-throughput computational structure prediction and validated by heavy-atom derivatization. Each repeat forms a left-handed, two-helix bundle that presents an RVD-containing loop to the DNA. The repeats self-associate to form a right-handed superhelix wrapped around the DNA major groove. The first RVD residue forms a stabilizing contact with the protein backbone, while the second makes a base-specific contact to the DNA sense strand. Two degenerate amino-terminal repeats also interact with the DNA. Containing several RVDs and noncanonical associations, the structure illustrates the basis of TAL effector-DNA recognition.
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Affiliation(s)
- Amanda Nga-Sze Mak
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, A3-025 Seattle, WA 98019, USA
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33
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Towards artificial metallonucleases for gene therapy: recent advances and new perspectives. Future Med Chem 2011; 3:1935-66. [DOI: 10.4155/fmc.11.139] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The process of DNA targeting or repair of mutated genes within the cell, induced by specifically positioned double-strand cleavage of DNA near the mutated sequence, can be applied for gene therapy of monogenic diseases. For this purpose, highly specific artificial metallonucleases are developed. They are expected to be important future tools of modern genetics. The present state of art and strategies of research are summarized, including protein engineering and artificial ‘chemical’ nucleases. From the results, we learn about the basic role of the metal ions and the various ligands, and about the DNA binding and cleavage mechanism. The results collected provide useful guidance for engineering highly controlled enzymes for use in gene therapy.
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34
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Kleinstiver BP, Bérubé-Janzen W, Fernandes AD, Edgell DR. Divalent metal ion differentially regulates the sequential nicking reactions of the GIY-YIG homing endonuclease I-BmoI. PLoS One 2011; 6:e23804. [PMID: 21887323 PMCID: PMC3161791 DOI: 10.1371/journal.pone.0023804] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Accepted: 07/26/2011] [Indexed: 01/30/2023] Open
Abstract
Homing endonucleases are site-specific DNA endonucleases that function as mobile genetic elements by introducing double-strand breaks or nicks at defined locations. Of the major families of homing endonucleases, the modular GIY-YIG endonucleases are least understood in terms of mechanism. The GIY-YIG homing endonuclease I-BmoI generates a double-strand break by sequential nicking reactions during which the single active site of the GIY-YIG nuclease domain must undergo a substantial reorganization. Here, we show that divalent metal ion plays a significant role in regulating the two independent nicking reactions by I-BmoI. Rate constant determination for each nicking reaction revealed that limiting divalent metal ion has a greater impact on the second strand than the first strand nicking reaction. We also show that substrate mutations within the I-BmoI cleavage site can modulate the first strand nicking reaction over a 314-fold range. Additionally, in-gel DNA footprinting with mutant substrates and modeling of an I-BmoI-substrate complex suggest that amino acid contacts to a critical GC-2 base pair are required to induce a bottom-strand distortion that likely directs conformational changes for reaction progress. Collectively, our data implies mechanistic roles for divalent metal ion and substrate bases, suggesting that divalent metal ion facilitates the re-positioning of the GIY-YIG nuclease domain between sequential nicking reactions.
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Affiliation(s)
- Benjamin P. Kleinstiver
- Department of Biochemistry, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - Wesley Bérubé-Janzen
- Department of Biochemistry, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - Andrew D. Fernandes
- Department of Biochemistry, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada
- Department of Applied Mathematics, The University of Western Ontario, London, Ontario, Canada
| | - David R. Edgell
- Department of Biochemistry, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada
- * E-mail:
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35
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Stoddard BL. Homing endonucleases: from microbial genetic invaders to reagents for targeted DNA modification. Structure 2011; 19:7-15. [PMID: 21220111 DOI: 10.1016/j.str.2010.12.003] [Citation(s) in RCA: 214] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Revised: 12/14/2010] [Accepted: 12/15/2010] [Indexed: 12/23/2022]
Abstract
Homing endonucleases are microbial DNA-cleaving enzymes that mobilize their own reading frames by generating double strand breaks at specific genomic invasion sites. These proteins display an economy of size, and yet recognize long DNA sequences (typically 20 to 30 base pairs). They exhibit a wide range of fidelity at individual nucleotide positions in a manner that is strongly influenced by host constraints on the coding sequence of the targeted gene. The activity of these proteins leads to site-specific recombination events that can result in the insertion, deletion, mutation, or correction of DNA sequences. Over the past fifteen years, the crystal structures of representatives from several homing endonuclease families have been solved, and methods have been described to create variants of these enzymes that cleave novel DNA targets. Engineered homing endonucleases proteins are now being used to generate targeted genomic modifications for a variety of biotech and medical applications.
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Affiliation(s)
- Barry L Stoddard
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N., A3-025, Seattle, WA 98109, USA.
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