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Montaño SP, Rowland SJ, Fuller JR, Burke ME, MacDonald A, Boocock M, Stark W, Rice P. Structural basis for topological regulation of Tn3 resolvase. Nucleic Acids Res 2023; 51:1001-1018. [PMID: 36100255 PMCID: PMC9943657 DOI: 10.1093/nar/gkac733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 08/02/2022] [Accepted: 08/16/2022] [Indexed: 11/13/2022] Open
Abstract
Site-specific DNA recombinases play a variety of biological roles, often related to the dissemination of antibiotic resistance, and are also useful synthetic biology tools. The simplest site-specific recombination systems will recombine any two cognate sites regardless of context. Other systems have evolved elaborate mechanisms, often sensing DNA topology, to ensure that only one of multiple possible recombination products is produced. The closely related resolvases from the Tn3 and γδ transposons have historically served as paradigms for the regulation of recombinase activity by DNA topology. However, despite many proposals, models of the multi-subunit protein-DNA complex (termed the synaptosome) that enforces this regulation have been unsatisfying due to a lack of experimental constraints and incomplete concordance with experimental data. Here, we present new structural and biochemical data that lead to a new, detailed model of the Tn3 synaptosome, and discuss how it harnesses DNA topology to regulate the enzymatic activity of the recombinase.
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Affiliation(s)
- Sherwin P Montaño
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Sally-J Rowland
- Institute of Molecular, Cell and Systems Biology, University of Glasgow, Bower Building, University Avenue, Glasgow G12 8QQ, Scotland, UK
| | - James R Fuller
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Mary E Burke
- Institute of Molecular, Cell and Systems Biology, University of Glasgow, Bower Building, University Avenue, Glasgow G12 8QQ, Scotland, UK
| | - Alasdair I MacDonald
- Institute of Molecular, Cell and Systems Biology, University of Glasgow, Bower Building, University Avenue, Glasgow G12 8QQ, Scotland, UK
| | - Martin R Boocock
- Institute of Molecular, Cell and Systems Biology, University of Glasgow, Bower Building, University Avenue, Glasgow G12 8QQ, Scotland, UK
| | - W Marshall Stark
- Institute of Molecular, Cell and Systems Biology, University of Glasgow, Bower Building, University Avenue, Glasgow G12 8QQ, Scotland, UK
| | - Phoebe A Rice
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA
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Control of the Serine Integrase Reaction: Roles of the Coiled-Coil and Helix E Regions in DNA Site Synapsis and Recombination. J Bacteriol 2021; 203:e0070320. [PMID: 34060907 DOI: 10.1128/jb.00703-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Bacteriophage serine integrases catalyze highly specific recombination reactions between defined DNA segments called att sites. These reactions are reversible depending upon the presence of a second phage-encoded directionality factor. The bipartite C-terminal DNA-binding region of integrases includes a recombinase domain (RD) connected to a zinc-binding domain (ZD), which contains a long flexible coiled-coil (CC) motif that extends away from the bound DNA. We directly show that the identities of the phage A118 integrase att sites are specified by the DNA spacing between the RD and ZD DNA recognition determinants, which in turn directs the relative trajectories of the CC motifs on each subunit of the att-bound integrase dimer. Recombination between compatible dimer-bound att sites requires minimal-length CC motifs and 14 residues surrounding the tip where the pairing of CC motifs between synapsing dimers occurs. Our alanine-scanning data suggest that molecular interactions between CC motif tips may differ in integrative (attP × attB) and excisive (attL × attR) recombination reactions. We identify mutations in 5 residues within the integrase oligomerization helix that control the remodeling of dimers into tetramers during synaptic complex formation. Whereas most of these gain-of-function mutants still require the CC motifs for synapsis, one mutant efficiently, but indiscriminately, forms synaptic complexes without the CC motifs. However, the CC motifs are still required for recombination, suggesting a function for the CC motifs after the initial assembly of the integrase synaptic tetramer. IMPORTANCE The robust and exquisitely regulated site-specific recombination reactions promoted by serine integrases are integral to the life cycle of temperate bacteriophage and, in the case of the A118 prophage, are an important virulence factor of Listeria monocytogenes. The properties of these recombinases have led to their repurposing into tools for genetic engineering and synthetic biology. In this report, we identify determinants regulating synaptic complex formation between correct DNA sites, including the DNA architecture responsible for specifying the identity of recombination sites, features of the unique coiled-coil structure on the integrase that are required to initiate synapsis, and amino acid residues on the integrase oligomerization helix that control the remodeling of synapsing dimers into a tetramer active for DNA strand exchange.
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Rowland SJ, Boocock MR, Burke ME, Rice PA, Stark WM. The protein-protein interactions required for assembly of the Tn3 resolution synapse. Mol Microbiol 2021; 114:952-965. [PMID: 33405333 DOI: 10.1111/mmi.14579] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 07/20/2020] [Accepted: 07/20/2020] [Indexed: 11/29/2022]
Abstract
The site-specific recombinase Tn3 resolvase initiates DNA strand exchange when two res recombination sites and six resolvase dimers interact to form a synapse. The detailed architecture of this intricate recombination machine remains unclear. We have clarified which of the potential dimer-dimer interactions are required for synapsis and recombination, using a novel complementation strategy that exploits a previously uncharacterized resolvase from Bartonella bacilliformis ("Bart"). Tn3 and Bart resolvases recognize different DNA motifs, via diverged C-terminal domains (CTDs). They also differ substantially at N-terminal domain (NTD) surfaces involved in dimerization and synapse assembly. We designed NTD-CTD hybrid proteins, and hybrid res sites containing both Tn3 and Bart dimer binding sites. Using these components in in vivo assays, we demonstrate that productive synapsis requires a specific "R" interface involving resolvase NTDs at all three dimer-binding sites in res. Synapses containing mixtures of wild-type Tn3 and Bart resolvase NTD dimers are recombination-defective, but activity can be restored by replacing patches of Tn3 resolvase R interface residues with Bart residues, or vice versa. We conclude that the Tn3/Bart family synapse is assembled exclusively by R interactions between resolvase dimers, except for the one special dimer-dimer interaction required for catalysis.
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Affiliation(s)
- Sally-J Rowland
- Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow, UK
| | - Martin R Boocock
- Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow, UK
| | - Mary E Burke
- Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow, UK
| | - Phoebe A Rice
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
| | - W Marshall Stark
- Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow, UK
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Sun Z, Liu Q, Qu G, Feng Y, Reetz MT. Utility of B-Factors in Protein Science: Interpreting Rigidity, Flexibility, and Internal Motion and Engineering Thermostability. Chem Rev 2019; 119:1626-1665. [PMID: 30698416 DOI: 10.1021/acs.chemrev.8b00290] [Citation(s) in RCA: 300] [Impact Index Per Article: 60.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Zhoutong Sun
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West Seventh Avenue, Tianjin Airport Economic Area, Tianjin 300308, China
| | - Qian Liu
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Ge Qu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West Seventh Avenue, Tianjin Airport Economic Area, Tianjin 300308, China
| | - Yan Feng
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Manfred T. Reetz
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West Seventh Avenue, Tianjin Airport Economic Area, Tianjin 300308, China
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
- Chemistry Department, Philipps-University, Hans-Meerwein-Strasse 4, 35032 Marburg, Germany
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