1
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Shibata T, Ikawa S, Iwasaki W, Sasanuma H, Masai H, Hirota K. Homology recognition without double-stranded DNA-strand separation in D-loop formation by RecA. Nucleic Acids Res 2024; 52:2565-2577. [PMID: 38214227 PMCID: PMC10954442 DOI: 10.1093/nar/gkad1260] [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: 09/05/2023] [Revised: 12/15/2023] [Accepted: 12/30/2023] [Indexed: 01/13/2024] Open
Abstract
RecA protein and RecA/Rad51 orthologues are required for homologous recombination and DNA repair in all living creatures. RecA/Rad51 catalyzes formation of the D-loop, an obligatory recombination intermediate, through an ATP-dependent reaction consisting of two phases: homology recognition between double-stranded (ds)DNA and single-stranded (ss)DNA to form a hybrid-duplex core of 6-8 base pairs and subsequent hybrid-duplex/D-loop processing. How dsDNA recognizes homologous ssDNA is controversial. The aromatic residue at the tip of the β-hairpin loop (L2) was shown to stabilize dsDNA-strand separation. We tested a model in which dsDNA strands were separated by the aromatic residue before homology recognition and found that the aromatic residue was not essential to homology recognition, but was required for D-loop processing. Contrary to the model, we found that the double helix was not unwound even a single turn during search for sequence homology, but rather was unwound only after the homologous sequence was recognized. These results suggest that dsDNA recognizes its homologous ssDNA before strand separation. The search for homologous sequence with homologous ssDNA without dsDNA-strand separation does not generate stress within the dsDNA; this would be an advantage for dsDNA to express homology-dependent functions in vivo and also in vitro.
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Affiliation(s)
- Takehiko Shibata
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, 1-1 Minami Ohsawa, Hachioji, Tokyo 192-0397, Japan
- Genome Dynamics Project, Department of Basic Medical Sciences, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan
- Cellular & Molecular Biology Laboratory, RIKEN, Wako-shi, Saitama 351-0198, Japan
| | - Shukuko Ikawa
- Cellular & Molecular Biology Laboratory, RIKEN, Wako-shi, Saitama 351-0198, Japan
| | - Wakana Iwasaki
- Laboratory for Translation Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Hiroyuki Sasanuma
- Genome Dynamics Project, Department of Basic Medical Sciences, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan
| | - Hisao Masai
- Genome Dynamics Project, Department of Basic Medical Sciences, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan
| | - Kouji Hirota
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, 1-1 Minami Ohsawa, Hachioji, Tokyo 192-0397, Japan
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2
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Fan H. Single‐molecule tethered particle motion to study
protein‐DNA
interaction. J CHIN CHEM SOC-TAIP 2023. [DOI: 10.1002/jccs.202300051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
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3
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Insights into homology search from cryo-EM structures of RecA-DNA recombination intermediates. Curr Opin Genet Dev 2021; 71:188-194. [PMID: 34592688 DOI: 10.1016/j.gde.2021.09.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 09/01/2021] [Accepted: 09/10/2021] [Indexed: 11/20/2022]
Abstract
The fundamental reaction in homologous recombination is the exchange of strands between two homologous DNA molecules. This reaction is carried out by the RecA family of ATPases that polymerize on ssDNA to form a presynaptic filament. This filament then binds to dsDNA to form a synaptic filament, a key intermediate that mediates the search for homology and subsequent strand exchange to produce a new heteroduplex. A recent cryo-EM analysis of synaptic filaments has now shed light on this process. The dsDNA strands are separated on binding to the filament. One strand is sequestrated while the other is freed to sample pairing with the ssDNA. Homology, through heteroduplex formation, promotes dsDNA opening. Lack of homology suppresses it, keeping local synapses short so that multiple synapses can form and increasing the probability of encountering homology.
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4
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Fan HF, Su S. The regulation mechanism of the C-terminus of RecA proteins during DNA strand-exchange process. Biophys J 2021; 120:3166-3179. [PMID: 34197804 DOI: 10.1016/j.bpj.2021.06.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 04/21/2021] [Accepted: 06/03/2021] [Indexed: 12/14/2022] Open
Abstract
The C-terminus of Escherichia coli RecA protein can affect the DNA binding affinity, interact with accessory proteins, and regulate the RecA activity. A substantial upward shift in the pH-reaction profile of RecA-mediated DNA strand-exchange reactions was observed for C-terminal-truncated E. coli ΔC17 RecA, Deinococcus radiodurans RecA, and Deinococcus ficus RecA. Here, the process of RecA-mediated strand exchange from the beginning to the end was investigated with florescence resonance energy transfer and tethered particle motion experiments to determine the detailed regulation mechanism. RecA proteins with a shorter C-terminus possess more stable nuclei, higher DNA binding affinities, and lower protonation requirements for the formation of nucleoprotein filaments. Moreover, more stable synaptic complexes in the homologous sequence searching process were also observed for RecA proteins with a shorter C-terminus. Our results suggest that the C-terminus of RecA proteins regulates not only the formation of RecA nucleoprotein filaments but also the entrance of secondary DNA into RecA nucleoprotein filaments.
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Affiliation(s)
- Hsiu-Fang Fan
- Institute of Medical Science and Technology, Kaohsiung, Taiwan; Department of Chemistry, Kaohsiung, Taiwan; Aerosol Science Research Center, National Sun Yat-sen University, Kaohsiung, Taiwan.
| | - Shu Su
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan
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5
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Yang H, Zhou C, Dhar A, Pavletich NP. Mechanism of strand exchange from RecA-DNA synaptic and D-loop structures. Nature 2020; 586:801-806. [PMID: 33057191 PMCID: PMC8366275 DOI: 10.1038/s41586-020-2820-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 09/10/2020] [Indexed: 02/08/2023]
Abstract
The strand exchange reaction is central to homologous recombination. It is catalyzed by the RecA family of ATPases that form a helical filament with single-stranded DNA (ssDNA) and ATP. This filament binds to a donor double-stranded DNA (dsDNA) to form synaptic filaments that search for homology, and then catalyze the exchange of the complementary strand to form a new heteroduplex, or a D-loop if homology is limited1,2. Here we report the Cryo-EM analysis of synaptic mini filaments with both non-complementary and partially-complementary dsDNA, and structures of RecA–D-loop complexes containing a 10 or 12 base pair heteroduplex at 2.8 and 2.9 Å, respectively. The RecA C-terminal domain (CTD) binds to dsDNA and directs it to the L2 loop, which inserts into and opens the duplex. The opening propagates through RecA sequestering the homologous strand at a secondary DNA-binding site, freeing the complementary strand to sample pairing with the ssDNA. Duplex opening has a significant probability of stopping at each RecA step, with the as yet unopened dsDNA portion binding to another CTD. Homology suppresses this process through heteroduplex pairing cooperating with secondary site-ssDNA binding to extend dsDNA opening. This mechanism locally limits the length of ssDNA sampled for pairing if homology is not encountered, and it may provide for the formation of multiple synapses separated substantially on the donor dsDNA, increasing the probability of encountering homology.
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Affiliation(s)
- Haijuan Yang
- Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
| | - Chun Zhou
- Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.,Zhejiang University School of Medicine, Zhejiang, China
| | - Ankita Dhar
- Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
| | - Nikola P Pavletich
- Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY, USA. .,Howard Hughes Medical Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
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6
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Fan HF, Su S, Kuo YA, Chen CJ. Influence of the C-Terminal Tail of RecA Proteins from Alkaline pH-Resistant Bacterium Deinococcus Ficus. ACS OMEGA 2020; 5:19868-19876. [PMID: 32803083 PMCID: PMC7424711 DOI: 10.1021/acsomega.0c02865] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 07/14/2020] [Indexed: 06/11/2023]
Abstract
Deinococcus ficus CC-FR2-10T, resistant to ultraviolet, ionizing radiation, and chemicals which may cause DNA damage, was identified in Taiwan. The expression level of D. ficus RecA, which has 92% sequence identity with Deinococcus radiodurans (Dr.) RecA, will be upregulated upon UV radiation. Multiple sequence alignment of RecA proteins from bacteria belonging to Escherichia coli and the Deinococcus genus reveals that the C-terminal tail of D. ficus RecA is shorter and contains less acidic residues than E. coli RecA. D. ficus RecA exhibits a higher ATPase activity toward single-stranded (ss) DNA and efficiently promotes DNA strand exchange that a filament is first formed on ssDNA, followed by uptake of the double-stranded (ds) substrate. Moreover, D. ficus RecA exhibits a pH-reaction profile for DNA strand exchange similar to E. coli ΔC17 RecA. Later, a chimera D. ficus C17 E. coli RecA with more acidic residues in the C-terminal tail was constructed and purified. Increased negativity in the C-terminal tail makes the pH reaction profile for Chimera D. ficus C17 E. coli RecA DNA strand exchange exhibit a reaction optimum similar to E. coli RecA. To sum up, D. ficus RecA exhibits reaction properties in substrate-dependent ATPase activity and DNA strand exchange similar to E. coli RecA. Our data indicate that the negativity in the C-terminal tail plays an important role in the regulation of pH-dependent DNA strand exchange activity.
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Affiliation(s)
- Hsiu-Fang Fan
- Institute
of Medical Science and Technology, National
Sun Yat-sen University, Kaohsiung 80424, Taiwan
- Department
of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
- Aerosol
Science Research Center, National Sun Yat-sen
University, Kaohsiung 80424, Taiwan
| | - Shu Su
- Department
of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei 11221, Taiwan
| | - Ying-An Kuo
- Department
of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei 11221, Taiwan
| | - Cyuan-Ji Chen
- Department
of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei 11221, Taiwan
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7
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Tavares EM, Wright WD, Heyer WD, Le Cam E, Dupaigne P. In vitro role of Rad54 in Rad51-ssDNA filament-dependent homology search and synaptic complexes formation. Nat Commun 2019; 10:4058. [PMID: 31492866 PMCID: PMC6731316 DOI: 10.1038/s41467-019-12082-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 08/12/2019] [Indexed: 11/28/2022] Open
Abstract
Homologous recombination (HR) uses a homologous template to accurately repair DNA double-strand breaks and stalled replication forks to maintain genome stability. During homology search, Rad51 nucleoprotein filaments probe and interact with dsDNA, forming the synaptic complex that is stabilized on a homologous sequence. Strand intertwining leads to the formation of a displacement-loop (D-loop). In yeast, Rad54 is essential for HR in vivo and required for D-loop formation in vitro, but its exact role remains to be fully elucidated. Using electron microscopy to visualize the DNA-protein complexes, here we find that Rad54 is crucial for Rad51-mediated synaptic complex formation and homology search. The Rad54−K341R ATPase-deficient mutant protein promotes formation of synaptic complexes but not D-loops and leads to the accumulation of stable heterologous associations, suggesting that the Rad54 ATPase is involved in preventing non-productive intermediates. We propose that Rad51/Rad54 form a functional unit operating in homology search, synaptic complex and D-loop formation. Homologous recombination uses a template to accurately repair DNA double-strand breaks and stalled replication forks to maintain genome stability. Here authors use electron microscopy to investigate the role of Rad54 in homology search and synaptic complex formation.
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Affiliation(s)
- Eliana Moreira Tavares
- Genome Maintenance and Molecular Microscopy UMR8126 CNRS, Université Paris-Sud, Université Paris-Saclay, Gustave Roussy, F-94805, Villejuif Cedex, France
| | - William Douglass Wright
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA, 95616-8665, USA
| | - Wolf-Dietrich Heyer
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA, 95616-8665, USA
| | - Eric Le Cam
- Genome Maintenance and Molecular Microscopy UMR8126 CNRS, Université Paris-Sud, Université Paris-Saclay, Gustave Roussy, F-94805, Villejuif Cedex, France
| | - Pauline Dupaigne
- Genome Maintenance and Molecular Microscopy UMR8126 CNRS, Université Paris-Sud, Université Paris-Saclay, Gustave Roussy, F-94805, Villejuif Cedex, France.
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8
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Kim R, Kanamaru S, Mikawa T, Prévost C, Ishii K, Ito K, Uchiyama S, Oda M, Iwasaki H, Kim SK, Takahashi M. RecA requires two molecules of Mg2+ ions for its optimal strand exchange activity in vitro. Nucleic Acids Res 2019; 46:2548-2559. [PMID: 29390145 PMCID: PMC5861410 DOI: 10.1093/nar/gky048] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Accepted: 01/23/2018] [Indexed: 11/15/2022] Open
Abstract
Mg2+ ion stimulates the DNA strand exchange reaction catalyzed by RecA, a key step in homologous recombination. To elucidate the molecular mechanisms underlying the role of Mg2+ and the strand exchange reaction itself, we investigated the interaction of RecA with Mg2+ and sought to determine which step of the reaction is affected. Thermal stability, intrinsic fluorescence, and native mass spectrometric analyses of RecA revealed that RecA binds at least two Mg2+ ions with KD ≈ 2 mM and 5 mM. Deletion of the C-terminal acidic tail of RecA made its thermal stability and fluorescence characteristics insensitive to Mg2+ and similar to those of full-length RecA in the presence of saturating Mg2+. These observations, together with the results of a molecular dynamics simulation, support the idea that the acidic tail hampers the strand exchange reaction by interacting with other parts of RecA, and that binding of Mg2+ to the tail prevents these interactions and releases RecA from inhibition. We observed that binding of the first Mg2+ stimulated joint molecule formation, whereas binding of the second stimulated progression of the reaction. Thus, RecA is actively involved in the strand exchange step as well as bringing the two DNAs close to each other.
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Affiliation(s)
- Raeyeong Kim
- Department of Chemistry, Yeungnam University, Gyeonsan-city 38541, Republic of Korea
| | - Shuji Kanamaru
- School of Life Science and Technology, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan.,Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Tsutomu Mikawa
- RIKEN Quantitative Biology Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Chantal Prévost
- Laboratoire de Biochimie Théorique, UPR9080 CNRS Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Kentaro Ishii
- Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan
| | - Kentaro Ito
- School of Life Science and Technology, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan.,Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Susumu Uchiyama
- Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan.,Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita 565-0871, Japan
| | - Masayuki Oda
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, 1-5 Hangi-cho, Shimogamo, Sakyo-ku, Kyoto 606-8522, Japan
| | - Hiroshi Iwasaki
- School of Life Science and Technology, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan.,Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Seog K Kim
- Department of Chemistry, Yeungnam University, Gyeonsan-city 38541, Republic of Korea
| | - Masayuki Takahashi
- School of Life Science and Technology, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
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9
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Shinohara T, Arai N, Iikura Y, Kasagi M, Masuda-Ozawa T, Yamaguchi Y, Suzuki-Nagata K, Shibata T, Mikawa T. Nonfilament-forming RecA dimer catalyzes homologous joint formation. Nucleic Acids Res 2018; 46:10855-10869. [PMID: 30285153 PMCID: PMC6237804 DOI: 10.1093/nar/gky877] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 09/19/2018] [Indexed: 01/18/2023] Open
Abstract
Homologous recombination is essential to genome maintenance, and also to genome diversification. In virtually all organisms, homologous recombination depends on the RecA/Rad51-family recombinases, which catalyze ATP-dependent formation of homologous joints—critical intermediates in homologous recombination. RecA/Rad51 binds first to single-stranded (ss) DNA at a damaged site to form a spiral nucleoprotein filament, after which double-stranded (ds) DNA interacts with the filament to search for sequence homology and to form consecutive base pairs with ssDNA (‘pairing’). How sequence homology is recognized and what exact role filament formation plays remain unknown. We addressed the question of whether filament formation is a prerequisite for homologous joint formation. To this end we constructed a nonpolymerizing (np) head-to-tail-fused RecA dimer (npRecA dimer) and an npRecA monomer. The npRecA dimer bound to ssDNA, but did not form continuous filaments upon binding to DNA; it formed beads-on-string structures exclusively. Although its efficiency was lower, the npRecA dimer catalyzed the formation of D-loops (a type of homologous joint), whereas the npRecA monomer was completely defective. Thus, filament formation contributes to efficiency, but is not essential to sequence-homology recognition and pairing, for which a head-to-tail dimer form of RecA protomer is required and sufficient.
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Affiliation(s)
- Takeshi Shinohara
- Cellular & Molecular Biology Laboratory, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
- RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
- Department of Supramolecular Biology, Graduate School of Nanobiosciences, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Naoto Arai
- Department of Applied Biological Science, Nihon University College of Bioresource Sciences, 1866 Kameino, Fujisawa-shi, Kanagawa 252-0880, Japan
| | - Yukari Iikura
- Cellular & Molecular Biology Laboratory, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
- RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
| | - Motochika Kasagi
- Cellular & Molecular Biology Laboratory, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
- Department of Supramolecular Biology, Graduate School of Nanobiosciences, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Tokiha Masuda-Ozawa
- Cellular & Molecular Biology Laboratory, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
- Department of Supramolecular Biology, Graduate School of Nanobiosciences, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Yuuki Yamaguchi
- Cellular & Molecular Biology Laboratory, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
- Department of Supramolecular Biology, Graduate School of Nanobiosciences, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Kayo Suzuki-Nagata
- RIKEN Quantitative Biology Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Takehiko Shibata
- Cellular & Molecular Biology Laboratory, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
- RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
- Department of Supramolecular Biology, Graduate School of Nanobiosciences, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minami-Osawa 1-1, Hachioji-shi, Tokyo 192-0397, Japan
- To whom correspondence should be addressed. Takehiko Shibata. Tel: +81 3 3950 2534; . Correspondence may also be addressed to Tsutomu Mikawa. Tel: +81 45 633 8013;
| | - Tsutomu Mikawa
- Cellular & Molecular Biology Laboratory, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
- Department of Supramolecular Biology, Graduate School of Nanobiosciences, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
- RIKEN Quantitative Biology Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
- RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
- To whom correspondence should be addressed. Takehiko Shibata. Tel: +81 3 3950 2534; . Correspondence may also be addressed to Tsutomu Mikawa. Tel: +81 45 633 8013;
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10
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Hutinet G, Besle A, Son O, McGovern S, Guerois R, Petit MA, Ochsenbein F, Lecointe F. Sak4 of Phage HK620 Is a RecA Remote Homolog With Single-Strand Annealing Activity Stimulated by Its Cognate SSB Protein. Front Microbiol 2018; 9:743. [PMID: 29740405 PMCID: PMC5928155 DOI: 10.3389/fmicb.2018.00743] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 03/29/2018] [Indexed: 12/19/2022] Open
Abstract
Bacteriophages are remarkable for the wide diversity of proteins they encode to perform DNA replication and homologous recombination. Looking back at these ancestral forms of life may help understanding how similar proteins work in more sophisticated organisms. For instance, the Sak4 family is composed of proteins similar to the archaeal RadB protein, a Rad51 paralog. We have previously shown that Sak4 allowed single-strand annealing in vivo, but only weakly compared to the phage λ Redβ protein, highlighting putatively that Sak4 requires partners to be efficient. Here, we report that the purified Sak4 of phage HK620 infecting Escherichia coli is a poorly efficient annealase on its own. A distant homolog of SSB, which gene is usually next to the sak4 gene in various species of phages, highly stimulates its recombineering activity in vivo. In vitro, Sak4 binds single-stranded DNA and performs single-strand annealing in an ATP-dependent way. Remarkably, the single-strand annealing activity of Sak4 is stimulated by its cognate SSB. The last six C-terminal amino acids of this SSB are essential for the binding of Sak4 to SSB-covered single-stranded DNA, as well as for the stimulation of its annealase activity. Finally, expression of sak4 and ssb from HK620 can promote low-level of recombination in vivo, though Sak4 and its SSB are unable to promote strand exchange in vitro. Regarding its homology with RecA, Sak4 could represent a link between two previously distinct types of recombinases, i.e., annealases that help strand exchange proteins and strand exchange proteins themselves.
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Affiliation(s)
- Geoffrey Hutinet
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Arthur Besle
- Institute for Integrative Biology of the Cell (I2BC), IBITECS, CEA, Centre National de la Recherche Scientifique, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Olivier Son
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Stephen McGovern
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Raphaël Guerois
- Institute for Integrative Biology of the Cell (I2BC), IBITECS, CEA, Centre National de la Recherche Scientifique, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Marie-Agnès Petit
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Françoise Ochsenbein
- Institute for Integrative Biology of the Cell (I2BC), IBITECS, CEA, Centre National de la Recherche Scientifique, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - François Lecointe
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
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11
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Wright WD, Shah SS, Heyer WD. Homologous recombination and the repair of DNA double-strand breaks. J Biol Chem 2018; 293:10524-10535. [PMID: 29599286 DOI: 10.1074/jbc.tm118.000372] [Citation(s) in RCA: 418] [Impact Index Per Article: 69.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Homologous recombination enables the cell to access and copy intact DNA sequence information in trans, particularly to repair DNA damage affecting both strands of the double helix. Here, we discuss the DNA transactions and enzymatic activities required for this elegantly orchestrated process in the context of the repair of DNA double-strand breaks in somatic cells. This includes homology search, DNA strand invasion, repair DNA synthesis, and restoration of intact chromosomes. Aspects of DNA topology affecting individual steps are highlighted. Overall, recombination is a dynamic pathway with multiple metastable and reversible intermediates designed to achieve DNA repair with high fidelity.
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Affiliation(s)
| | | | - Wolf-Dietrich Heyer
- From the Departments of Microbiology and Molecular Genetics and .,Molecular and Cellular Biology, University of California, Davis, Davis, California 95616-8665
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12
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Lee AJ, Sharma R, Hobbs JK, Wälti C. Cooperative RecA clustering: the key to efficient homology searching. Nucleic Acids Res 2017; 45:11743-11751. [PMID: 28977583 PMCID: PMC5714135 DOI: 10.1093/nar/gkx769] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 08/25/2017] [Indexed: 01/17/2023] Open
Abstract
The mechanism by which pre-synaptic RecA nucleoprotein filaments efficiently locate sequence homology across genomic DNA remains unclear. Here, using atomic force microscopy, we directly investigate the intermediates of the RecA-mediated homologous recombination process and find it to be highly cooperative, involving multiple phases. Initially, the process is dominated by a rapid ‘association’ phase, where multiple filaments interact on the same dsDNA simultaneously. This cooperative nature is reconciled by the observation of localized dense clusters of pre-synaptic filaments interacting with the observed dsDNA molecules. This confinement of reactive species within the vicinity of the dsDNA, is likely to play an important role in ensuring that a high interaction rate between the nucleoprotein filaments and the dsDNA can be achieved. This is followed by a slower ‘resolution’ phase, where the synaptic joints either locate sequence homology and progress to a post-synaptic joint, or dissociate from the dsDNA. Surprisingly, the number of simultaneous synaptic joints decreases rapidly after saturation of the dsDNA population, suggesting a reduction in interaction activity of the RecA filaments. We find that the time-scale of this decay is in line with the time-scale of the dispersion of the RecA filament clusters, further emphasising the important role this cooperative phenomena may play in the RecA-facilitated homology search.
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Affiliation(s)
- Andrew J Lee
- Bioelectronics Group, School of Electronic & Electrical Engineering, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK.,Department of Physics and Astronomy, University of Sheffield, Hounsfield Road, Sheffield, S3 7RH, UK
| | - Rajan Sharma
- Bioelectronics Group, School of Electronic & Electrical Engineering, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
| | - Jamie K Hobbs
- Department of Physics and Astronomy, University of Sheffield, Hounsfield Road, Sheffield, S3 7RH, UK.,The Krebs Institute, University of Sheffield, Sheffield, S10 2TN, UK
| | - Christoph Wälti
- Bioelectronics Group, School of Electronic & Electrical Engineering, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
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13
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Rajpurohit YS, Bihani SC, Waldor MK, Misra HS. Phosphorylation of Deinococcus radiodurans RecA Regulates Its Activity and May Contribute to Radioresistance. J Biol Chem 2016; 291:16672-85. [PMID: 27255712 DOI: 10.1074/jbc.m116.736389] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Indexed: 11/06/2022] Open
Abstract
Deinococcus radiodurans has a remarkable capacity to survive exposure to extreme levels of radiation that cause hundreds of DNA double strand breaks (DSBs). DSB repair in this bacterium depends on its recombinase A protein (DrRecA). DrRecA plays a pivotal role in both extended synthesis-dependent strand annealing and slow crossover events of DSB repair during the organism's recovery from DNA damage. The mechanisms that control DrRecA activity during the D. radiodurans response to γ radiation exposure are unknown. Here, we show that DrRecA undergoes phosphorylation at Tyr-77 and Thr-318 by a DNA damage-responsive serine threonine/tyrosine protein kinase (RqkA). Phosphorylation modifies the activity of DrRecA in several ways, including increasing its affinity for dsDNA and its preference for dATP over ATP. Strand exchange reactions catalyzed by phosphorylated versus unphosphorylated DrRecA also differ. In silico analysis of DrRecA structure support the idea that phosphorylation can modulate crucial functions of this protein. Collectively, our findings suggest that phosphorylation of DrRecA enables the recombinase to selectively use abundant dsDNA substrate present during post-irradiation recovery for efficient DSB repair, thereby promoting the extraordinary radioresistance of D. radiodurans.
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Affiliation(s)
| | - Subhash C Bihani
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai-400085, India and
| | - Matthew K Waldor
- the Division of Infectious Diseases and Howard Hughes Medical Institute, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115
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14
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Marsh ME, Scott DE, Ehebauer MT, Abell C, Blundell TL, Hyvönen M. ATP half-sites in RadA and RAD51 recombinases bind nucleotides. FEBS Open Bio 2016; 6:372-85. [PMID: 27419043 PMCID: PMC4856416 DOI: 10.1002/2211-5463.12052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 03/03/2016] [Indexed: 12/20/2022] Open
Abstract
Homologous recombination is essential for repair of DNA double-strand breaks. Central to this process is a family of recombinases, including archeal RadA and human RAD51, which form nucleoprotein filaments on damaged single-stranded DNA ends and facilitate their ATP-dependent repair. ATP binding and hydrolysis are dependent on the formation of a nucleoprotein filament comprising RadA/RAD51 and single-stranded DNA, with ATP bound between adjacent protomers. We demonstrate that truncated, monomeric Pyrococcus furiosus RadA and monomerised human RAD51 retain the ability to bind ATP and other nucleotides with high affinity. We present crystal structures of both apo and nucleotide-bound forms of monomeric RadA. These structures reveal that while phosphate groups are tightly bound, RadA presents a shallow, poorly defined binding surface for the nitrogenous bases of nucleotides. We suggest that RadA monomers would be constitutively bound to nucleotides in the cell and that the bound nucleotide might play a structural role in filament assembly.
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Affiliation(s)
- May E Marsh
- Department of Biochemistry University of Cambridge UK; Present address: Paul Scherrer Institut Villingen Switzerland
| | | | - Matthias T Ehebauer
- Department of Biochemistry University of Cambridge UK; Present address: Target Discovery Institute Nuffield Department of Medicine University of Oxford UK
| | - Chris Abell
- Department of Chemistry University of Cambridge UK
| | | | - Marko Hyvönen
- Department of Biochemistry University of Cambridge UK
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15
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Prentiss M, Prévost C, Danilowicz C. Structure/function relationships in RecA protein-mediated homology recognition and strand exchange. Crit Rev Biochem Mol Biol 2015; 50:453-76. [DOI: 10.3109/10409238.2015.1092943] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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16
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Yang D, Boyer B, Prévost C, Danilowicz C, Prentiss M. Integrating multi-scale data on homologous recombination into a new recognition mechanism based on simulations of the RecA-ssDNA/dsDNA structure. Nucleic Acids Res 2015; 43:10251-63. [PMID: 26384422 PMCID: PMC4666392 DOI: 10.1093/nar/gkv883] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 08/23/2015] [Indexed: 12/11/2022] Open
Abstract
RecA protein is the prototypical recombinase. Members of the recombinase family can accurately repair double strand breaks in DNA. They also provide crucial links between pairs of sister chromatids in eukaryotic meiosis. A very broad outline of how these proteins align homologous sequences and promote DNA strand exchange has long been known, as are the crystal structures of the RecA-DNA pre- and postsynaptic complexes; however, little is known about the homology searching conformations and the details of how DNA in bacterial genomes is rapidly searched until homologous alignment is achieved. By integrating a physical model of recognition to new modeling work based on docking exploration and molecular dynamics simulation, we present a detailed structure/function model of homology recognition that reconciles extremely quick searching with the efficient and stringent formation of stable strand exchange products and which is consistent with a vast body of previously unexplained experimental results.
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Affiliation(s)
- Darren Yang
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Benjamin Boyer
- Laboratoire de Biochimie Théorique, CNRS UPR 9080, Univ Paris Diderot, Sorbonne Paris Cité, IBPC, Paris, France
| | - Chantal Prévost
- Laboratoire de Biochimie Théorique, CNRS UPR 9080, Univ Paris Diderot, Sorbonne Paris Cité, IBPC, Paris, France
| | | | - Mara Prentiss
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
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17
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Danilowicz C, Yang D, Kelley C, Prévost C, Prentiss M. The poor homology stringency in the heteroduplex allows strand exchange to incorporate desirable mismatches without sacrificing recognition in vivo. Nucleic Acids Res 2015; 43:6473-85. [PMID: 26089391 PMCID: PMC4513875 DOI: 10.1093/nar/gkv610] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 05/31/2015] [Indexed: 11/15/2022] Open
Abstract
RecA family proteins are responsible for homology search and strand exchange. In bacteria, homology search begins after RecA binds an initiating single-stranded DNA (ssDNA) in the primary DNA-binding site, forming the presynaptic filament. Once the filament is formed, it interrogates double-stranded DNA (dsDNA). During the interrogation, bases in the dsDNA attempt to form Watson–Crick bonds with the corresponding bases in the initiating strand. Mismatch dependent instability in the base pairing in the heteroduplex strand exchange product could provide stringent recognition; however, we present experimental and theoretical results suggesting that the heteroduplex stability is insensitive to mismatches. We also present data suggesting that an initial homology test of 8 contiguous bases rejects most interactions containing more than 1/8 mismatches without forming a detectable 20 bp product. We propose that, in vivo, the sparsity of accidental sequence matches allows an initial 8 bp test to rapidly reject almost all non-homologous sequences. We speculate that once the initial test is passed, the mismatch insensitive binding in the heteroduplex allows short mismatched regions to be incorporated in otherwise homologous strand exchange products even though sequences with less homology are eventually rejected.
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Affiliation(s)
| | - Darren Yang
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Craig Kelley
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - Chantal Prévost
- Laboratoire de Biochimie Théorique, CNRS UPR 9080, Univ. Paris Diderot, Sorbonne Paris Cité, IBPC, Paris, France
| | - Mara Prentiss
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
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18
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Kou WZ, Xu SL, Wang Y, Wang LW, Wang L, Chai XY, Hua QL. Expression of Kin17 promotes the proliferation of hepatocellular carcinoma cells in vitro and in vivo.. Oncol Lett 2014; 8:1190-1194. [PMID: 25120685 PMCID: PMC4114639 DOI: 10.3892/ol.2014.2244] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2013] [Accepted: 04/04/2014] [Indexed: 11/06/2022] Open
Abstract
Kin17 protein is ubiquitously expressed in mammals and is correlated with vital biological functions. However, little is known about the role of Kin17 in the proliferation of hepatocellular carcinoma cells. The aim of the present study was to investigate whether the upregulation of Kin17 can promote the growth of hepatocellular carcinoma cells. A series of assays was performed to study the effect of Kin17 in the proliferation of hepatocellular carcinoma cells in vitro and in vivo. The western blotting results revealed that Kin17 expression was increased in hepatocellular carcinoma tissues compared with that of the corresponding normal tissues. Moreover, ectopic upregulation of Kin17 expression promoted the growth of hepatocellular carcinoma cells in vitro and in vivo. These results indicated that Kin17 is involved in the tumorigenesis of hepatocellular carcinoma, and that Kin17 has the potential to serve as a therapeutic target for hepatocellular carcinoma.
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Affiliation(s)
- Wei-Zheng Kou
- Department of Oncology, First Affiliated Hospital of Xinxiang Medical University, Weihui, Henan 453100, P.R. China
| | - Su-Ling Xu
- Department of Oncology, First Affiliated Hospital of Xinxiang Medical University, Weihui, Henan 453100, P.R. China
| | - Ying Wang
- Department of Oncology, First Affiliated Hospital of Xinxiang Medical University, Weihui, Henan 453100, P.R. China
| | - Li-Wei Wang
- Department of Ultrasound, First Affiliated Hospital of Xinxiang Medical University, Weihui, Henan 453100, P.R. China
| | - Lei Wang
- Department of Laboratory, First Affiliated Hospital of Xinxiang Medical University, Weihui, Henan 453100, P.R. China
| | - Xiao-Yan Chai
- Department of Cardiology, First Affiliated Hospital of Xinxiang Medical University, Weihui, Henan 453100, P.R. China
| | - Qin-Liang Hua
- Department of Oncology, First Affiliated Hospital of Xinxiang Medical University, Weihui, Henan 453100, P.R. China
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19
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Lisboa J, Andreani J, Sanchez D, Boudes M, Collinet B, Liger D, van Tilbeurgh H, Guérois R, Quevillon-Cheruel S. Molecular determinants of the DprA-RecA interaction for nucleation on ssDNA. Nucleic Acids Res 2014; 42:7395-408. [PMID: 24782530 PMCID: PMC4066776 DOI: 10.1093/nar/gku349] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Natural transformation is a major mechanism of horizontal gene transfer in bacteria that depends on DNA recombination. RecA is central to the homologous recombination pathway, catalyzing DNA strand invasion and homology search. DprA was shown to be a key binding partner of RecA acting as a specific mediator for its loading on the incoming exogenous ssDNA. Although the 3D structures of both RecA and DprA have been solved, the mechanisms underlying their cross-talk remained elusive. By combining molecular docking simulations and experimental validation, we identified a region on RecA, buried at its self-assembly interface and involving three basic residues that contact an acidic triad of DprA previously shown to be crucial for the interaction. At the core of these patches, DprAM238 and RecAF230 are involved in the interaction. The other DprA binding regions of RecA could involve the N-terminal α-helix and a DNA-binding region. Our data favor a model of DprA acting as a cap of the RecA filament, involving a DprA−RecA interplay at two levels: their own oligomeric states and their respective interaction with DNA. Our model forms the basis for a mechanistic explanation of how DprA can act as a mediator for the loading of RecA on ssDNA.
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Affiliation(s)
- Johnny Lisboa
- Université Paris-Sud, Institut de Biochimie et de Biophysique Moléculaire et Cellulaire, UMR 8619, F-91405 Orsay, France
| | - Jessica Andreani
- CEA, iBiTecS, F-91191 Gif sur Yvette, France Université Paris-Sud & CNRS, UMR 8221, F-91191 Gif sur Yvette, France
| | - Dyana Sanchez
- Université Paris-Sud, Institut de Biochimie et de Biophysique Moléculaire et Cellulaire, UMR 8619, F-91405 Orsay, France
| | - Marion Boudes
- Université Paris-Sud, Institut de Biochimie et de Biophysique Moléculaire et Cellulaire, UMR 8619, F-91405 Orsay, France
| | - Bruno Collinet
- Université Paris-Sud, Institut de Biochimie et de Biophysique Moléculaire et Cellulaire, UMR 8619, F-91405 Orsay, France UFR sciences de la vie, Université Pierre et Marie Curie UPMC, Sorbonne Universités, F-75005 Paris, France
| | - Dominique Liger
- Université Paris-Sud, Institut de Biochimie et de Biophysique Moléculaire et Cellulaire, UMR 8619, F-91405 Orsay, France
| | - Herman van Tilbeurgh
- Université Paris-Sud, Institut de Biochimie et de Biophysique Moléculaire et Cellulaire, UMR 8619, F-91405 Orsay, France
| | - Raphael Guérois
- CEA, iBiTecS, F-91191 Gif sur Yvette, France Université Paris-Sud & CNRS, UMR 8221, F-91191 Gif sur Yvette, France
| | - Sophie Quevillon-Cheruel
- Université Paris-Sud, Institut de Biochimie et de Biophysique Moléculaire et Cellulaire, UMR 8619, F-91405 Orsay, France
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20
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Rao DECS, Luo Y. pH-dependent activities and structural stability of loop-2-anchoring helix of RadA recombinase from Methanococcus voltae. Protein Pept Lett 2014; 21:679-87. [PMID: 24654848 PMCID: PMC4150490 DOI: 10.2174/0929866521666140320103512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 02/25/2014] [Accepted: 02/27/2014] [Indexed: 11/22/2022]
Abstract
RadA is an archaeal orthologue of human recombinase Rad51. This superfamily of recombinases, which also includes eukaryal meiosis-specific DMC1 and remotely related bacterial RecA, form filaments on single-stranded DNA in the presence of ATP and promote a strand exchange reaction between the single-stranded DNA and a homologous double-stranded DNA. Due to its feasibility of getting crystals and similarity (> 40% sequence identity) to eukaryal homologues, we have studied RadA from Methanococcus voltae (MvRadA) as a structural model for understanding the molecular mechanism of homologous strand exchange. Here we show this protein’s ATPase and strand exchange activities are minimal at pH 6.0. Interestingly, MvRadA’s pH dependence is similar to the properties of human Rad51 but dissimilar to that of the well-studied E. coli RecA. A structure subsequently determined at pH 6.0 reveals features indicative of an ATPase-inactive form with a disordered L2 loop. Comparison with a previously determined ATPase-active form at pH 7.5 implies that the stability of the ATPase-active conformation is reduced at the acidic pH. We interpret these results as further suggesting an ordered disposition of the DNA-binding L2 region, similar to what has been observed in the previously observed ATPase-active conformation, is required for promoting hydrolysis of ATP and strand exchange between single- and double-stranded DNA. His-276 in the mobile L2 region was observed to be partially responsible for the pH-dependent activities of MvRadA.
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Affiliation(s)
| | - Yu Luo
- Department of Biochemistry, University of Saskatchewan, 2D01 Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan, Canada S7N 5E5.
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21
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Qin S, Zhou HX. Structural models of protein-DNA complexes based on interface prediction and docking. Curr Protein Pept Sci 2012; 12:531-9. [PMID: 21787304 DOI: 10.2174/138920311796957694] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 04/01/2011] [Accepted: 05/04/2011] [Indexed: 11/22/2022]
Abstract
Protein-DNA interactions are the physical basis of gene expression and DNA modification. Structural models that reveal these interactions are essential for their understanding. As only a limited number of structures for protein-DNA complexes have been determined by experimental methods, computation methods provide a potential way to fill the need. We have developed the DISPLAR method to predict DNA binding sites on proteins. Predicted binding sites have been used to assist the building of structural models by docking, either by guiding the docking or by selecting near-native candidates from the docked poses. Here we applied the DISPLAR method to predict the DNA binding sites for 20 DNA-binding proteins, which have had their DNA binding sites characterized by NMR chemical shift perturbation. For two of these proteins, the structures of their complexes with DNA have also been determined. With the help of the DISPLAR predictions, we built structural models for these two complexes. Evaluations of both the DNA binding sites for 20 proteins and the structural models of the two protein-DNA complexes against experimental results demonstrate the significant promise of our model-building approach.
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Affiliation(s)
- Sanbo Qin
- Department of Physics and Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306, USA
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22
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Amunugama R, Fishel R. Homologous Recombination in Eukaryotes. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2012; 110:155-206. [DOI: 10.1016/b978-0-12-387665-2.00007-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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23
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Aramini JM, Rossi P, Fischer M, Xiao R, Acton TB, Montelione GT. Solution NMR structure of VF0530 from Vibrio fischeri reveals a nucleic acid-binding function. Proteins 2011; 79:2988-91. [PMID: 21905121 DOI: 10.1002/prot.23121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2011] [Revised: 06/10/2011] [Accepted: 06/15/2011] [Indexed: 11/11/2022]
Abstract
Protein domain family PF09905 (DUF2132) is a family of small domains of unknown function that are conserved in a wide range of bacteria. Here we describe the solution NMR structure of the 80-residue VF0530 protein from Vibrio fischeri, the first structural representative from this protein domain family. We demonstrate that the structure of VF0530 adopts a unique four-helix motif that shows some similarity to the C-terminal double-stranded DNA (dsDNA) binding domain of RecA, as well as other nucleic acid binding domains. Moreover, gel shift binding data indicate a potential dsDNA binding role for VF0530.
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Affiliation(s)
- James M Aramini
- Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, USA.
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24
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Adikesavan AK, Katsonis P, Marciano DC, Lua R, Herman C, Lichtarge O. Separation of recombination and SOS response in Escherichia coli RecA suggests LexA interaction sites. PLoS Genet 2011; 7:e1002244. [PMID: 21912525 PMCID: PMC3164682 DOI: 10.1371/journal.pgen.1002244] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Accepted: 06/29/2011] [Indexed: 12/29/2022] Open
Abstract
RecA plays a key role in homologous recombination, the induction of the DNA damage response through LexA cleavage and the activity of error-prone polymerase in Escherichia coli. RecA interacts with multiple partners to achieve this pleiotropic role, but the structural location and sequence determinants involved in these multiple interactions remain mostly unknown. Here, in a first application to prokaryotes, Evolutionary Trace (ET) analysis identifies clusters of evolutionarily important surface amino acids involved in RecA functions. Some of these clusters match the known ATP binding, DNA binding, and RecA-RecA homo-dimerization sites, but others are novel. Mutation analysis at these sites disrupted either recombination or LexA cleavage. This highlights distinct functional sites specific for recombination and DNA damage response induction. Finally, our analysis reveals a composite site for LexA binding and cleavage, which is formed only on the active RecA filament. These new sites can provide new drug targets to modulate one or more RecA functions, with the potential to address the problem of evolution of antibiotic resistance at its root. In eubacteria, genome integrity is in large part orchestrated by RecA, which directly participates in recombination, induction of DNA damage response through LexA repressor cleavage and error-prone DNA synthesis. Yet, most of the interaction sites necessary for these vital processes are largely unknown. By comparing divergences among RecA sequences and computing putative functional regions, we discovered four functional sites of RecA. Targeted point-mutations were then tested for both recombination and DNA damage induction and reveal distinct RecA functions at each one of these sites. In particular, one new set of mutants is deficient in promoting LexA cleavage and yet maintains the ability to induce the DNA damage response. These results reveal specific amino acid determinants of the RecA–LexA interaction and suggest that LexA binds RecAi and RecAi+6 at a composite site on the RecA filament, which could explain the role of the active filament during LexA cleavage.
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Affiliation(s)
- Anbu K Adikesavan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
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25
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Crystal structure of the phage T4 recombinase UvsX and its functional interaction with the T4 SF2 helicase UvsW. J Mol Biol 2010; 405:65-76. [PMID: 21035462 DOI: 10.1016/j.jmb.2010.10.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Revised: 10/01/2010] [Accepted: 10/06/2010] [Indexed: 11/23/2022]
Abstract
Bacteriophage T4 provides an important model system for studying the mechanism of homologous recombination. We have determined the crystal structure of the T4 UvsX recombinase, and the overall architecture and fold closely resemble those of RecA, including a highly conserved ATP binding site. Based on this new structure, we reanalyzed electron microscopy reconstructions of UvsX-DNA filaments and docked the UvsX crystal structure into two different filament forms: a compressed filament generated in the presence of ADP and an elongated filament generated in the presence of ATP and aluminum fluoride. In these reconstructions, the ATP binding site sits at the protomer interface, as in the RecA filament crystal structure. However, the environment of the ATP binding site is altered in the two filament reconstructions, suggesting that nucleotide cannot be as easily accommodated at the protomer interface of the compressed filament. Finally, we show that the phage helicase UvsW completes the UvsX-promoted strand-exchange reaction, allowing the generation of a simple nicked circular product rather than complex networks of partially exchanged substrates.
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26
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Carra C, Cucinotta FA. Binding selectivity of RecA to a single stranded DNA, a computational approach. J Mol Model 2010; 17:133-50. [PMID: 20386943 DOI: 10.1007/s00894-010-0694-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Accepted: 02/23/2010] [Indexed: 11/29/2022]
Abstract
Homologous recombination (HR) is the major DNA double strand break repair pathway which maintains the genomic integrity. It is fundamental for the survivability and functionality of all organisms. One of the initial steps in HR is the formation of the nucleoprotein filament composed by a single stranded DNA chain surrounded by the recombinases protein. The filament orchestrates the search for an undamaged homologue, as a template for the repair process. Our theoretical study was aimed at elucidating the selectivity of the interaction between a monomer of the recombinases enzyme in the Escherichia coli, EcRecA, the bacterial homologue of human Rad51, with a series of oligonucleotides of nine bases length. The complex, equilibrated for 20 ns with Langevian dynamics, was inserted in a periodic box with a 8 Å buffer of water molecules explicitly described by the TIP3P model. The absolute binding free energies are calculated in an implicit solvent using the Poisson-Boltzmann (PB) and the generalized Born (GB) solvent accessible surface area, using the MM-PB(GB)SA model. The solute entropic contribution is also calculated by normal mode analysis. The results underline how a significant contribution of the binding free energy is due to the interaction with the Arg196, a critical amino acid for the activity of the enzyme. The study revealed how the binding affinity of EcRecA is significantly higher toward dT₉ rather than dA₉, as expected from the experimental results.
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Affiliation(s)
- Claudio Carra
- Universities Space Research Association, 2101 NASA Parkway, Houston, TX 77058, USA.
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27
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Carra C, Cucinotta FA. Binding Sites of theE. ColiDNA Recombinase Protein to the ssDNA: A Computational Study. J Biomol Struct Dyn 2010; 27:407-28. [DOI: 10.1080/07391102.2010.10507327] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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28
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Lee CD, Wang TF. The N-terminal domain of Escherichia coli RecA have multiple functions in promoting homologous recombination. J Biomed Sci 2009; 16:37. [PMID: 19338667 PMCID: PMC2672939 DOI: 10.1186/1423-0127-16-37] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2009] [Accepted: 04/01/2009] [Indexed: 11/26/2022] Open
Abstract
Escherichia coli RecA mediates homologous recombination, a process essential to maintaining genome integrity. In the presence of ATP, RecA proteins bind a single-stranded DNA (ssDNA) to form a RecA-ssDNA presynaptic nucleoprotein filament that captures donor double-stranded DNA (dsDNA), searches for homology, and then catalyzes the strand exchange between ssDNA and dsDNA to produce a new heteroduplex DNA. Based upon a recently reported crystal structure of the RecA-ssDNA nucleoprotein filament, we carried out structural and functional studies of the N-terminal domain (NTD) of the RecA protein. The RecA NTD was thought to be required for monomer-monomer interaction. Here we report that it has two other distinct roles in promoting homologous recombination. It first facilitates the formation of a RecA-ssDNA presynaptic nucleoprotein filament by converting ATP to an ADP-Pi intermediate. Then, once the RecA-ssDNA presynaptic nucleoprotein filament is stably assembled in the presence of ATPγS, the NTD is required to capture donor dsDNA. Our results also suggest that the second function of NTD may be similar to that of Arg243 and Lys245, which were implicated earlier as binding sites of donor dsDNA. A two-step model is proposed to explain how a RecA-ssDNA presynaptic nucleoprotein filament interacts with donor dsDNA.
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Affiliation(s)
- Chien-Der Lee
- Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan.
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Chang YW, Ko TP, Lee CD, Chang YC, Lin KA, Chang CS, Wang AHJ, Wang TF. Three new structures of left-handed RADA helical filaments: structural flexibility of N-terminal domain is critical for recombinase activity. PLoS One 2009; 4:e4890. [PMID: 19295907 PMCID: PMC2654063 DOI: 10.1371/journal.pone.0004890] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2009] [Accepted: 02/19/2009] [Indexed: 12/02/2022] Open
Abstract
RecA family proteins, including bacterial RecA, archaeal RadA, and eukaryotic Dmc1 and Rad51, mediate homologous recombination, a reaction essential for maintaining genome integrity. In the presence of ATP, these proteins bind a single-strand DNA to form a right-handed nucleoprotein filament, which catalyzes pairing and strand exchange with a homologous double-stranded DNA (dsDNA), by as-yet unknown mechanisms. We recently reported a structure of RadA left-handed helical filament, and here present three new structures of RadA left-handed helical filaments. Comparative structural analysis between different RadA/Rad51 helical filaments reveals that the N-terminal domain (NTD) of RadA/Rad51, implicated in dsDNA binding, is highly flexible. We identify a hinge region between NTD and polymerization motif as responsible for rigid body movement of NTD. Mutant analysis further confirms that structural flexibility of NTD is essential for RadA's recombinase activity. These results support our previous hypothesis that ATP-dependent axial rotation of RadA nucleoprotein helical filament promotes homologous recombination.
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Affiliation(s)
- Yu-Wei Chang
- Institute of Biochemical Science, National Taiwan University, Taipei, Taiwan
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Tzu-Ping Ko
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Chien-Der Lee
- Institute of Biochemical Science, National Taiwan University, Taipei, Taiwan
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | | | - Kuei-Ann Lin
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | | | - Andrew H.-J. Wang
- Institute of Biochemical Science, National Taiwan University, Taipei, Taiwan
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
- * E-mail: (AHJW); (TFW)
| | - Ting-Fang Wang
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
- * E-mail: (AHJW); (TFW)
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Zhang XP, Galkin VE, Yu X, Egelman EH, Heyer WD. Loop 2 in Saccharomyces cerevisiae Rad51 protein regulates filament formation and ATPase activity. Nucleic Acids Res 2008; 37:158-71. [PMID: 19033358 PMCID: PMC2615628 DOI: 10.1093/nar/gkn914] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Previous studies showed that the K342E substitution in the Saccharomyces cerevisiae Rad51 protein increases the interaction with Rad54 protein in the two-hybrid system, leads to increased sensitivity to the alkylating agent MMS and hyper-recombination in an oligonucleotide-mediated gene targeting assay. K342 localizes in loop 2, a region of Rad51 whose function is not well understood. Here, we show that Rad51-K342E displays DNA-independent and DNA-dependent ATPase activities, owing to its ability to form filaments in the absence of a DNA lattice. These filaments exhibit a compressed pitch of 81 Å, whereas filaments of wild-type Rad51 and Rad51-K342E on DNA form extended filaments with a 97 Å pitch. Rad51-K342E shows near normal binding to ssDNA, but displays a defect in dsDNA binding, resulting in less stable protein-dsDNA complexes. The mutant protein is capable of catalyzing the DNA strand exchange reaction and is insensitive to inhibition by the early addition of dsDNA. Wild-type Rad51 protein is inhibited under such conditions, because of its ability to bind dsDNA. No significant changes in the interaction between Rad51-K342E and Rad54 could be identified. These findings suggest that loop 2 contributes to the primary DNA-binding site in Rad51, controlling filament formation and ATPase activity.
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Affiliation(s)
- Xiao-Ping Zhang
- Department of Microbiology, University of California, Davis, CA 95616-8665, USA
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31
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Abstract
The bacterial RecA protein participates in a remarkably diverse set of functions, all of which are involved in the maintenance of genomic integrity. RecA is a central component in both the catalysis of recombinational DNA repair and the regulation of the cellular SOS response. Despite the mechanistic differences of its functions, all require formation of an active RecA/ATP/DNA complex. RecA is a classic allosterically regulated enzyme, and ATP binding results in a dramatic increase in DNA binding affinity and a cooperative assembly of RecA subunits to form an ordered, helical nucleoprotein filament. The molecular events that underlie this ATP-induced structural transition are becoming increasingly clear. This review focuses on descriptions of our current understanding of the molecular design and allosteric regulation of RecA. We present a comprehensive list of all published recA mutants and use the results of various genetic and biochemical studies, together with available structural information, to develop ideas regarding the design of RecA functional domains and their catalytic organization.
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Affiliation(s)
- Dharia A McGrew
- Department of Biochemistry and Molecular Pharmacology, Aaron Lazare Research Building, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605-2324, USA
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Protein structure prediction by all-atom free-energy refinement. BMC STRUCTURAL BIOLOGY 2007; 7:12. [PMID: 17371594 PMCID: PMC1832197 DOI: 10.1186/1472-6807-7-12] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2006] [Accepted: 03/19/2007] [Indexed: 11/18/2022]
Abstract
Background The reliable prediction of protein tertiary structure from the amino acid sequence remains challenging even for small proteins. We have developed an all-atom free-energy protein forcefield (PFF01) that we could use to fold several small proteins from completely extended conformations. Because the computational cost of de-novo folding studies rises steeply with system size, this approach is unsuitable for structure prediction purposes. We therefore investigate here a low-cost free-energy relaxation protocol for protein structure prediction that combines heuristic methods for model generation with all-atom free-energy relaxation in PFF01. Results We use PFF01 to rank and cluster the conformations for 32 proteins generated by ROSETTA. For 22/10 high-quality/low quality decoy sets we select near-native conformations with an average Cα root mean square deviation of 3.03 Å/6.04 Å. The protocol incorporates an inherent reliability indicator that succeeds for 78% of the decoy sets. In over 90% of these cases near-native conformations are selected from the decoy set. This success rate is rationalized by the quality of the decoys and the selectivity of the PFF01 forcefield, which ranks near-native conformations an average 3.06 standard deviations below that of the relaxed decoys (Z-score). Conclusion All-atom free-energy relaxation with PFF01 emerges as a powerful low-cost approach toward generic de-novo protein structure prediction. The approach can be applied to large all-atom decoy sets of any origin and requires no preexisting structural information to identify the native conformation. The study provides evidence that a large class of proteins may be foldable by PFF01.
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Egel R. RecA-DNA filament topology: the overlooked alternative of an unconventional syn-syn duplex intermediate. DNA Repair (Amst) 2007; 6:669-75. [PMID: 17317338 DOI: 10.1016/j.dnarep.2006.12.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2006] [Revised: 12/17/2006] [Accepted: 12/21/2006] [Indexed: 10/23/2022]
Abstract
The helical filaments of RecA protein mediate strand exchange for homologous recombination, but the paths of the interacting DNAs have yet to be determined. Although this interaction is commonly limited to three strands, it is reasoned here that the intrinsic symmetry relationships of quadruplex topology are superior in explaining a range of observations. In particular, this topology suggests the potential of post-exchange base pairing in the unorthodox configuration of syn-syn glycosidic bonds between the nucleotide bases and the pentose rings in the sugar-phosphate backbone, which would transiently be stabilized by the external scaffolding of the RecA protein filament.
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Affiliation(s)
- Richard Egel
- Institute of Molecular Biology and Physiology, University of Copenhagen, Ole Maaløe Vej 5, DK-2100 Copenhagen Ø, Denmark.
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Krishna R, Prabu JR, Manjunath GP, Datta S, Chandra NR, Muniyappa K, Vijayan M. Snapshots of RecA protein involving movement of the C-domain and different conformations of the DNA-binding loops: crystallographic and comparative analysis of 11 structures of Mycobacterium smegmatis RecA. J Mol Biol 2007; 367:1130-44. [PMID: 17306300 DOI: 10.1016/j.jmb.2007.01.058] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2006] [Revised: 01/17/2007] [Accepted: 01/22/2007] [Indexed: 10/23/2022]
Abstract
Mycobacterium smegmatis RecA and its nucleotide complexes crystallize in three different, but closely related, forms characterized by specific ranges of unit cell dimensions. The six crystals reported here and five reported earlier, all grown under the same or very similar conditions, belong to these three forms, all in space group P6(1). They include one obtained by reducing relative humidity around the crystal. In all crystals, RecA monomers form filaments around a 6(1) screw axis. Thus, the c-dimension of the crystal corresponds to the pitch of the RecA filament. As reported for Escherichia coli RecA, the variation in the pitch among the three forms correlates well with the motion of the C-terminal domain of the RecA monomers with respect to the main domain. The domain motion is compatible with formation of inactive as well as active RecA filaments involving monomers with a fully ordered C domain. It does not appear to influence the movement upon nucleotide-binding of the switch residue, which is believed to provide the trigger for transmitting the effect of nucleotide binding to the DNA-binding region. Interestingly, partial dehydration of the crystal results in the movement of the residue similar to that caused by nucleotide binding. The ordering of the DNA-binding loops, which present ensembles of conformations, is also unaffected by domain motion. The conformation of loop L2 appears to depend upon nucleotide binding, presumably on account of the movement of the switch residue that forms part of the loop. The conformations of loops L1 and L2 are correlated and have implications for intermolecular communications within the RecA filament. The structures resulting from different orientations of the C domain and different conformations of the DNA-binding loops appear to represent snapshots of the RecA at different phases of activity, and provide insights into the mechanism of action of RecA.
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Affiliation(s)
- R Krishna
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560 012, India
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35
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Fonseca MM, Alarcon FJ, Vasconcelos ATD, Agnez-Lima LF. A model for the RecA protein of Mycoplasma synoviae. Genet Mol Biol 2007. [DOI: 10.1590/s1415-47572007000200018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Qian X, He Y, Wu Y, Luo Y. Asp302 determines potassium dependence of a RadA recombinase from Methanococcus voltae. J Mol Biol 2006; 360:537-47. [PMID: 16782126 DOI: 10.1016/j.jmb.2006.05.058] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2005] [Revised: 04/12/2006] [Accepted: 05/23/2006] [Indexed: 12/20/2022]
Abstract
Archaeal RadA/Rad51 are close homologues of eukaryal Rad51/DMC1. Such recombinases, as well as their bacterial RecA orthologues, form helical nucleoprotein filaments in which a hallmark strand exchange reaction occurs between homologous DNA substrates. Our recent ATPase and structure studies on RadA recombinase from Methanococcus voltae have suggested that not only magnesium but also potassium ions are absorbed at the ATPase center. Potassium, but not sodium, stimulates the ATP hydrolysis reaction with an apparent dissociation constant of approximately 40 mM. The minimal inhibitory effect by 40 mM NaCl further suggests that the protein does not have adequate affinity for sodium. The wild-type protein's strand exchange activity is also stimulated by potassium with an apparent dissociation constant of approximately 35 mM. We made site-directed mutations at the potassium-contacting residues Glu151 and Asp302. The mutant proteins are expectedly defective in promoting ATP hydrolysis. Similar potassium preference in strand exchange is observed for the E151D and E151K proteins. The D302K protein, however, shows comparable strand exchange efficiencies in the presence of either potassium or sodium. Crystallized E151D filaments reveal a potassium-dependent conformational change similar to what has previously been observed with the wild-type protein. We interpret these data as suggesting that both ATP hydrolysis and DNA strand exchange requires accessibility to an "active" conformation similar to the crystallized ATPase-active form in the presence of ATP, Mg2+ and K+.
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Affiliation(s)
- Xinguo Qian
- Department of Biochemistry, University of Saskatchewan, A3 Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan, Canada S7N 5E5
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37
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Galkin VE, Wu Y, Zhang XP, Qian X, He Y, Yu X, Heyer WD, Luo Y, Egelman EH. The Rad51/RadA N-Terminal Domain Activates Nucleoprotein Filament ATPase Activity. Structure 2006; 14:983-92. [PMID: 16765891 DOI: 10.1016/j.str.2006.04.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2006] [Revised: 04/08/2006] [Accepted: 04/10/2006] [Indexed: 10/24/2022]
Abstract
Proteins in the RecA/RadA/Rad51 family form helical filaments on DNA that function in homologous recombination. While these proteins all have the same highly conserved ATP binding core, the RadA/Rad51 proteins have an N-terminal domain that shows no homology with the C-terminal domain found in RecA. Both the Rad51 N-terminal and RecA C-terminal domains have been shown to bind DNA, but no role for these domains has been established. We show that RadA filaments can be trapped in either an inactive or active conformation with respect to the ATPase and that activation involves a large rotation of the subunit aided by the N-terminal domain. The G103E mutation within the yeast Rad51 N-terminal domain inactivates the filament by failing to make proper contacts between the N-terminal domain and the core. These results show that the N-terminal domains play a regulatory role in filament activation and highlight the modular architecture of the recombination proteins.
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Affiliation(s)
- Vitold E Galkin
- Department of Biochemistry and Molecular Genetics, University of Virginia, Box 800733, Charlottesville, Virginia 22908, USA
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38
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Krishna R, Manjunath GP, Kumar P, Surolia A, Chandra NR, Muniyappa K, Vijayan M. Crystallographic identification of an ordered C-terminal domain and a second nucleotide-binding site in RecA: new insights into allostery. Nucleic Acids Res 2006; 34:2186-95. [PMID: 16648362 PMCID: PMC1450331 DOI: 10.1093/nar/gkl107] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2005] [Revised: 09/16/2005] [Accepted: 03/08/2006] [Indexed: 11/13/2022] Open
Abstract
RecA protein is a crucial and central component of the homologous recombination and DNA repair machinery. Despite numerous studies on the protein, several issues concerning its action, including the allosteric regulation mechanism have remained unclear. Here we report, for the first time, a crystal structure of a complex of Mycobacterium smegmatis RecA (MsRecA) with dATP, which exhibits a fully ordered C-terminal domain, with a second dATP molecule bound to it. ATP binding is an essential step for all activities of RecA, since it triggers the formation of active nucleoprotein filaments. In the crystal filament, dATP at the first site communicates with a dATP of the second site of an adjacent subunit, through conserved residues, suggesting a new route for allosteric regulation. In addition, subtle but definite changes observed in the orientation of the nucleotide at the first site and in the positions of the segment preceding loop L2 as well as in the segment 102-105 situated between the 2 nt, all appear to be concerted and suggestive of a biological role for the second bound nucleotide.
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Affiliation(s)
- R. Krishna
- Molecular Biophysics Unit, Indian Institute of ScienceBangalore 560 012, India
- Department of Biochemistry, Indian Institute of ScienceBangalore 560 012, India
- Bioinformatics Centre and Supercomputer Education and Research Centre, Indian Institute of ScienceBangalore 560 012, India
| | - G. P. Manjunath
- Department of Biochemistry, Indian Institute of ScienceBangalore 560 012, India
| | - P. Kumar
- Molecular Biophysics Unit, Indian Institute of ScienceBangalore 560 012, India
- Department of Biochemistry, Indian Institute of ScienceBangalore 560 012, India
- Bioinformatics Centre and Supercomputer Education and Research Centre, Indian Institute of ScienceBangalore 560 012, India
| | - A. Surolia
- Molecular Biophysics Unit, Indian Institute of ScienceBangalore 560 012, India
- Department of Biochemistry, Indian Institute of ScienceBangalore 560 012, India
- Bioinformatics Centre and Supercomputer Education and Research Centre, Indian Institute of ScienceBangalore 560 012, India
| | - Nagasuma R. Chandra
- Bioinformatics Centre and Supercomputer Education and Research Centre, Indian Institute of ScienceBangalore 560 012, India
| | - K. Muniyappa
- Department of Biochemistry, Indian Institute of ScienceBangalore 560 012, India
| | - M. Vijayan
- Correspondence may also be addressed to M. Vijayan. Tel: +91 80 22932590; Fax: +91 80 23600535;
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39
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Abstract
RecA protein catalyses an ATP-dependent DNA strand-exchange reaction that is the central step in the repair of dsDNA breaks by homologous recombination. Although much is known about the structure of RecA protein itself, we do not at present have a detailed picture of how RecA binds to ssDNA and dsDNA substrates, and how these interactions are controlled by the binding and hydrolysis of the ATP cofactor. Recent studies from electron microscopy and X-ray crystallography have revealed important ATP-mediated conformational changes that occur within the protein, providing new insights into how RecA catalyses DNA strand-exchange. A unifying theme is emerging for RecA and related ATPase enzymes in which the binding of ATP at a subunit interface results in large conformational changes that are coupled to interactions with the substrates in such a way as to promote the desired reactions.
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Affiliation(s)
- Charles E Bell
- Department of Molecular and Cellular Biochemistry, Ohio State University College of Medicine and Public Health, 371 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210, USA.
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40
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Möller HM, Martinez-Yamout MA, Dyson HJ, Wright PE. Solution Structure of the N-terminal Zinc Fingers of the Xenopus laevis double-stranded RNA-binding Protein ZFa. J Mol Biol 2005; 351:718-30. [PMID: 16051273 DOI: 10.1016/j.jmb.2005.06.032] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2005] [Revised: 06/03/2005] [Accepted: 06/08/2005] [Indexed: 10/25/2022]
Abstract
Several zinc finger proteins have been discovered recently that bind specifically to double-stranded RNA. These include the mammalian JAZ and wig proteins, and the seven-zinc finger protein ZFa from Xenopus laevis. We have determined the solution structure of a 127 residue fragment of ZFa, which consists of two zinc finger domains connected by a linker that remains unstructured in the free protein in solution. The first zinc finger consists of a three-stranded beta-sheet and three helices, while the second finger contains only a two-stranded sheet and two helices. The common structures of the core regions of the two fingers are superimposable. Each finger has a highly electropositive surface that maps to a helix-kink-helix motif. There is no evidence for interactions between the two fingers, consistent with the length (24 residues) and unstructured nature of the intervening linker. Comparison with a number of other proteins shows similarities in the topology and arrangement of secondary structure elements with canonical DNA-binding zinc fingers, with protein interaction motifs such as FOG zinc fingers, and with other DNA-binding and RNA-binding proteins that do not contain zinc. However, in none of these cases does the alignment of these structures with the ZFa zinc fingers produce a consistent picture of a plausible RNA-binding interface. We conclude that the ZFa zinc fingers represent a new motif for the binding of double-stranded RNA.
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Affiliation(s)
- Heiko M Möller
- Department of Molecular Biology and Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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41
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Galkin VE, Esashi F, Yu X, Yang S, West SC, Egelman EH. BRCA2 BRC motifs bind RAD51-DNA filaments. Proc Natl Acad Sci U S A 2005; 102:8537-42. [PMID: 15937124 PMCID: PMC1150802 DOI: 10.1073/pnas.0407266102] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Germ-line mutations in BRCA2 account for approximately half the cases of autosomal dominant familial breast cancers. BRCA2 has been shown to interact directly with RAD51, an essential component of the cellular machinery for homologous recombination and the maintenance of genome stability. Interactions between BRCA2 and RAD51 take place by means of the conserved BRC repeat regions of BRCA2. Previously, it was shown that peptides corresponding to BRC3 or BRC4 bind RAD51 monomers and block RAD51-DNA filament formation. In this work, we further analyze these interactions and find that at lower molar ratios BRC3 or BRC4 actually bind and form stable complexes with RAD51-DNA nucleoprotein filaments. Only at high concentrations of the BRC repeats are filaments disrupted. The specific protein-protein contacts occur in the RAD51 filament by means of the N-terminal domain of RAD51 for BRC3 and the nucleotide-binding core of RAD51 for BRC4. These observations show that the BRC repeats bind distinct regions of RAD51 and are nonequivalent in their mode of interaction. The results provide insight into why mutation in just one of the eight BRC repeats would affect the way that BRCA2 protein interacts with the RAD51 filament. Disruption of a single RAD51 interaction site, one of several simultaneous interactions occurring throughout the BRC repeat-containing exon 11 of BRCA2, might modulate the ability of RAD51 to promote recombinational repair and lead to an increased risk of breast cancer.
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Affiliation(s)
- Vitold E Galkin
- Department of Biochemistry and Molecular Genetics, University of Virginia Health Sciences Center, Charlottesville, VA 22908-0733, USA
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42
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Zhang XP, Lee KI, Solinger JA, Kiianitsa K, Heyer WD. Gly-103 in the N-terminal domain of Saccharomyces cerevisiae Rad51 protein is critical for DNA binding. J Biol Chem 2005; 280:26303-11. [PMID: 15908697 DOI: 10.1074/jbc.m503244200] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Rad51 is a homolog of the bacterial RecA protein and is central for recombination in eukaryotes performing homology search and DNA strand exchange. Rad51 and RecA share a core ATPase domain that is structurally similar to the ATPase domains of helicases and the F1 ATPase. Rad51 has an additional N-terminal domain, whereas RecA protein has an additional C-terminal domain. Here we show that glycine 103 in the N-terminal domain of Saccharomyces cerevisiae Rad51 is important for binding to single-stranded and duplex DNA. The Rad51-G103E mutant protein is deficient in DNA strand exchange and ATPase activity due to a primary DNA binding defect. The N-terminal domain of Rad51 is connected to the ATPase core through an extended elbow linker that ensures flexibility of the N-terminal domain. Molecular modeling of the Rad51-G103E mutant protein shows that the negatively charged glutamate residue lies on the surface of the N-terminal domain facing a positively charged patch composed of Arg-260, His-302, and Lys-305 on the ATPase core domain. A possible structural explanation for the DNA binding defect is that a charge interaction between Glu-103 and the positive patch restricts the flexibility of the N-terminal domain. Rad51-G103E was identified in a screen for Rad51 interaction-deficient mutants and was shown to ablate the Rad54 interaction in two-hybrid assays (Krejci, L., Damborsky, J., Thomsen, B., Duno, M., and Bendixen, C. (2001) Mol. Cell. Biol. 21, 966-976). Surprisingly, we found that the physical interaction of Rad51-G103E with Rad54 was not affected. Our data suggest that the two-hybrid interaction defect was an indirect consequence of the DNA binding defect.
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Affiliation(s)
- Xiao-Ping Zhang
- Section of Microbiology, University of California, Davis, California 95616-8665, USA
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43
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Rajan R, Bell CE. Crystal structure of RecA from Deinococcus radiodurans: insights into the structural basis of extreme radioresistance. J Mol Biol 2005; 344:951-63. [PMID: 15544805 DOI: 10.1016/j.jmb.2004.09.087] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2004] [Revised: 09/27/2004] [Accepted: 09/28/2004] [Indexed: 11/15/2022]
Abstract
The resistance of Deinococcus radiodurans (Dr) to extreme doses of ionizing radiation depends on its highly efficient capacity to repair dsDNA breaks. Dr RecA, the key protein in the repair of dsDNA breaks by homologous recombination, promotes DNA strand-exchange by an unprecedented inverse pathway, in which the presynaptic filament is formed on dsDNA instead of ssDNA. In order to gain insight into the remarkable repair capacity of Dr and the novel mechanistic features of its RecA protein, we have determined its X-ray crystal structure in complex with ATPgammaS at 2.5A resolution. Like RecA from Escherichia coli, Dr RecA crystallizes as a helical filament that is closely related to its biologically relevant form, but with a more compressed pitch of 67 A. Although the overall fold of Dr RecA is similar to E.coli RecA, there is a large reorientation of the C-terminal domain, which in E.coli RecA has a site for binding dsDNA. Compared to E.coli RecA, the inner surface along the central axis of the Dr RecA filament has an increased positive electrostatic potential. Unique amino acid residues in Dr RecA cluster around a flexible beta-hairpin that has also been implicated in DNA binding.
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Affiliation(s)
- Rakhi Rajan
- Department of Molecular and Cellular Biochemistry, Ohio State University College of Medicine and Public Health, 371 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210, USA
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44
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Xing X, Bell CE. Crystal structures of Escherichia coli RecA in complex with MgADP and MnAMP-PNP. Biochemistry 2005; 43:16142-52. [PMID: 15610008 DOI: 10.1021/bi048165y] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
RecA catalyzes the DNA pairing and strand-exchange steps of homologous recombination, an important mechanism for repair of double-stranded DNA breaks. The binding of RecA to DNA is modulated by adenosine nucleotides. ATP increases the affinity of RecA for DNA, while ADP decreases the affinity. Previously, the crystal structures of E. coli RecA and its complex with ADP have been determined to resolutions of 2.3 and 3.0 A, respectively, but the model for the RecA-ADP complex did not include magnesium ion or side chains. Here, we have determined the crystal structures of RecA in complex with MgADP and MnAMP-PNP, a nonhydrolyzable analogue of ATP, at resolutions of 1.9 and 2.1 A, respectively. Both crystals grow in the same conditions and have RecA in a right-handed helical form with a pitch of approximately 82 A. The crystal structures show the detailed interactions of RecA with the nucleotide cofactors, including the metal ion and the gamma phosphate of AMP-PNP. There are very few conformational differences between the structures of RecA bound to ADP and AMP-PNP, which differ from uncomplexed RecA only in a slight opening of the P-loop residues 66-73 upon nucleotide binding. To interpret the functional significance of the structure of the MnAMP-PNP complex, a coprotease assay was used to compare the ability of different nucleotides to promote the active, extended conformation of RecA. Whereas ATPgammaS and ADP-AlF(4) facilitate a robust coprotease activity, ADP and AMP-PNP do not activate RecA at all. We conclude that the crystal structure of the RecA-MnAMP-PNP complex represents a preisomerization state of the RecA protein that exists after ATP has bound but before the conformational transition to the active state.
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Affiliation(s)
- Xu Xing
- Department of Molecular and Cellular Biochemistry, Ohio State University College of Medicine and Public Health, 371 Hamilton Hall, 1645 Neil Avenue, Columbus, Ohio 43210, USA
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Wu Y, Qian X, He Y, Moya IA, Luo Y. Crystal structure of an ATPase-active form of Rad51 homolog from Methanococcus voltae. Insights into potassium dependence. J Biol Chem 2004; 280:722-8. [PMID: 15537659 DOI: 10.1074/jbc.m411093200] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Homologous gene recombination is crucial for the repair of DNA. A superfamily of recombinases facilitate a central strand exchange reaction in the repair process. This reaction is initiated by coating single-stranded DNA (ssDNA) with recombinases in the presence of ATP and Mg(2+) co-factors to form helical nucleoprotein filaments with elevated ATPase and strand invasion activities. At the amino acid sequence level, archaeal RadA and Rad51 and eukaryal Rad51 and meiosis-specific DMC1 form a closely related group of recombinases distinct from bacterial RecA. Unlike the extensively studied Escherichia coli RecA (EcRecA), increasing evidences on yeast and human recombinases imply that their optimal activities are dependent on the presence of a monovalent cation, particularly potassium. Here we present the finding that archaeal RadA from Methanococcus voltae (MvRadA) is a stringent potassium-dependent ATPase, and the crystal structure of this protein in complex with the non-hydrolyzable ATP analog adenosine 5'-(beta,gamma-iminotriphosphate), Mg(2+), and K(+) at 2.4 A resolution. Potassium triggered an in situ conformational change in the ssDNA-binding L2 region concerted with incorporation of two potassium ions at the ATPase site in the RadA crystals preformed in K(+)-free medium. Both potassium ions were observed in contact with the gamma-phosphate of the ATP analog, implying a direct role by the monovalent cations in stimulating the ATPase activity. Cross-talk between the ATPase site and the ssDNA-binding L2 region visualized in the MvRadA structure provides an explanation to the co-factor-induced allosteric effect on RecA-like recombinases.
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Affiliation(s)
- Yan Wu
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
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Xing X, Bell CE. Crystal structures of Escherichia coli RecA in a compressed helical filament. J Mol Biol 2004; 342:1471-85. [PMID: 15364575 DOI: 10.1016/j.jmb.2004.07.091] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2004] [Revised: 07/26/2004] [Accepted: 07/27/2004] [Indexed: 11/29/2022]
Abstract
The X-ray crystal structure of uncomplexed Escherichia coli RecA protein has been determined in three new crystal forms at resolutions of 1.9 A, 2.0 A, and 2.6 A. The RecA protein used for this study contains the extra residues Gly-Ser-His-Met at the N terminus, but retains normal ssDNA-dependent ATPase and coprotease activities. In all three crystals, RecA is packed in a right-handed helical filament with a pitch of approximately 74 A. These RecA filaments are compressed relative to the original crystal structure of RecA, which has a helical pitch of 82.7 A. In the structures of the compressed RecA filament, the monomer-monomer interface and the core domain are essentially the same as in the RecA structure with the 83 A pitch. The change in helical pitch is accommodated by a small movement of the N-terminal domain, which is reoriented to preserve the contacts it makes at the monomer-monomer interface. The new crystal structures show significant variation in the orientation and conformation of the C-terminal domain, as well as in the inter-filament packing interactions. In crystal form 2, a calcium ion is bound closely to a beta-hairpin of the C-terminal domain and to Asp38 of a neighboring filament, and residues 329-331 of the C-terminal tail become ordered to contact a neighboring filament. In crystal forms 3 and 4, a sulfate ion or a phosphate anion is bound to the same site on RecA as the beta-phosphate group of ADP, causing an opening of the P-loop. Altogether, the structures show the conformational variability of RecA protein in the crystalline state, providing insight into many aspects of RecA function.
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Affiliation(s)
- Xu Xing
- Department of Molecular and Cellular Biochemistry, Ohio State University College of Medicine and Public Health, 371 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210, USA
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Wu Y, He Y, Moya IA, Qian X, Luo Y. Crystal structure of archaeal recombinase RADA: a snapshot of its extended conformation. Mol Cell 2004; 15:423-35. [PMID: 15304222 DOI: 10.1016/j.molcel.2004.07.014] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2004] [Revised: 06/25/2004] [Accepted: 06/29/2004] [Indexed: 12/18/2022]
Abstract
Homologous recombination of DNA plays crucial roles in repairing severe DNA damage and in generating genetic diversity. The process is facilitated by a superfamily of recombinases: bacterial RecA, archaeal RadA and Rad51, and eukaryal Rad51 and DMC1. These recombinases share a common ATP-dependent filamentous quaternary structure for binding DNA and facilitating strand exchange. We have determined the crystal structure of Methanococcus voltae RadA in complex with the ATP analog AMP-PNP at 2.0 A resolution. The RadA filament is a 106.7 A pitch helix with six subunits per turn. The DNA binding loops L1 and L2 are located in close proximity to the filament axis. The ATP analog is buried between two RadA subunits, a feature similar to that of the active filament of Escherichia coli RecA revealed by electron microscopy. The disposition of the N-terminal domain suggests a role of the Helix-hairpin-Helix motif in binding double-stranded DNA.
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Affiliation(s)
- Yan Wu
- Department of Biochemistry, University of Saskatchewan, A3 Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan, Canada S7N 5E5
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Andrä J, Garidel P, Majerle A, Jerala R, Ridge R, Paus E, Novitsky T, Koch MHJ, Brandenburg K. Biophysical characterization of the interaction of Limulus polyphemus endotoxin neutralizing protein with lipopolysaccharide. ACTA ACUST UNITED AC 2004; 271:2037-46. [PMID: 15128313 DOI: 10.1111/j.1432-1033.2004.04134.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Endotoxin-neutralizing protein (ENP) of the horseshoe crab is one of the most potent neutralizers of endotoxins [bacterial lipopolysaccharide (LPS)]. Here, we report on the interaction of LPS with recombinant ENP using a variety of physical and biological techniques. In biological assays (Limulus amebocyte lysate and tumour necrosis factor-alpha induction in human mononuclear cells), ENP causes a strong reduction of the immunostimulatory ability of LPS in a dose-dependent manner. Concomitantly, the accessible negative surface charges of LPS and lipid A (zeta potential) are neutralized and even converted into positive values. The gel to liquid crystalline phase transitions of LPS and lipid A shift to higher temperatures indicative of a rigidification of the acyl chains, however, the only slight enhancement of the transition enthalpy indicates that the hydrophobic moiety is not strongly disturbed. The aggregate structure of lipid A is converted from a cubic into a multilamellar phase upon ENP binding, whereas the secondary structure of ENP does not change due to the interaction with LPS. ENP contains a hydrophobic binding site to which the dye 1-anilino-8-sulfonic acid binds at a K(d) of 19 micro m, which is displaced by LPS. Because lipopolysaccharide-binding protein (LBP) is not able to bind to LPS when ENP and LPS are preincubated, tight binding of ENP to LPS can be deduced with a K(d) in the low nonomolar range. Importantly, ENP is able to incorporate by itself into target phospholipid liposomes, and is also able to mediate the intercalation of LPS into the liposomes thus acting as a transport protein in a manner similar to LBP. Thus, LPS-ENP complexes might enter target membranes of immunocompetent cells, but are not able to activate due to the ability of ENP to change LPS aggregates from an active into an inactive form.
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Affiliation(s)
- Jörg Andrä
- Forschungszentrum Borstel, Leibniz-Zentrum für Medizin und Biowissenschaften, Borstel, Germany
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Shin DS, Pellegrini L, Daniels DS, Yelent B, Craig L, Bates D, Yu DS, Shivji MK, Hitomi C, Arvai AS, Volkmann N, Tsuruta H, Blundell TL, Venkitaraman AR, Tainer JA. Full-length archaeal Rad51 structure and mutants: mechanisms for RAD51 assembly and control by BRCA2. EMBO J 2003; 22:4566-76. [PMID: 12941707 PMCID: PMC202371 DOI: 10.1093/emboj/cdg429] [Citation(s) in RCA: 216] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
To clarify RAD51 interactions controlling homologous recombination, we report here the crystal structure of the full-length RAD51 homolog from Pyrococcus furiosus. The structure reveals how RAD51 proteins assemble into inactive heptameric rings and active DNA-bound filaments matching three-dimensional electron microscopy reconstructions. A polymerization motif (RAD51-PM) tethers individual subunits together to form assemblies. Subunit interactions support an allosteric 'switch' promoting ATPase activity and DNA binding roles for the N-terminal domain helix-hairpin-helix (HhH) motif. Structural and mutational results characterize RAD51 interactions with the breast cancer susceptibility protein BRCA2 in higher eukaryotes. A designed P.furiosus RAD51 mutant binds BRC repeats and forms BRCA2-dependent nuclear foci in human cells in response to gamma-irradiation-induced DNA damage, similar to human RAD51. These results show that BRCA2 repeats mimic the RAD51-PM and imply analogous RAD51 interactions with RAD52 and RAD54. Both BRCA2 and RAD54 may act as antagonists and chaperones for RAD51 filament assembly by coupling RAD51 interface exchanges with DNA binding. Together, these structural and mutational results support an interface exchange hypothesis for coordinated protein interactions in homologous recombination.
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Affiliation(s)
- David S Shin
- Department of Molecular Biology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
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Abstract
Many proteins function as helical polymers within the cell. Two intensively studied examples are eukaryotic actin and bacterial RecA, which belong to two different protein superfamilies. However, most other members of these superfamilies do not polymerize into helical filaments. General features of polymorphism, cooperativity and allostery that emerge from studies of eukaryotic actin and bacterial RecA raise more general issues about how conserved these filamentous structures have been during evolution.
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Affiliation(s)
- Edward H Egelman
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, Virginia 22908-0733, USA.
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