1
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Peñafiel-Ayala A, Peralta-Castro A, Mora-Garduño J, García-Medel P, Zambrano-Pereira AG, Díaz-Quezada C, Abraham-Juárez MJ, Benítez-Cardoza CG, Sloan DB, Brieba LG. Plant Organellar MSH1 Is a Displacement Loop-Specific Endonuclease. PLANT & CELL PHYSIOLOGY 2024; 65:560-575. [PMID: 37756637 DOI: 10.1093/pcp/pcad112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 09/09/2023] [Accepted: 09/19/2023] [Indexed: 09/29/2023]
Abstract
MutS HOMOLOG 1 (MSH1) is an organellar-targeted protein that obstructs ectopic recombination and the accumulation of mutations in plant organellar genomes. MSH1 also modulates the epigenetic status of nuclear DNA, and its absence induces a variety of phenotypic responses. MSH1 is a member of the MutS family of DNA mismatch repair proteins but harbors an additional GIY-YIG nuclease domain that distinguishes it from the rest of this family. How MSH1 hampers recombination and promotes fidelity in organellar DNA inheritance is unknown. Here, we elucidate its enzymatic activities by recombinantly expressing and purifying full-length MSH1 from Arabidopsis thaliana (AtMSH1). AtMSH1 is a metalloenzyme that shows a strong binding affinity for displacement loops (D-loops). The DNA-binding abilities of AtMSH1 reside in its MutS domain and not in its GIY-YIG domain, which is the ancillary nickase of AtMSH1. In the presence of divalent metal ions, AtMSH1 selectively executes multiple incisions at D-loops, but not other DNA structures including Holliday junctions or dsDNA, regardless of the presence or absence of mismatches. The selectivity of AtMSH1 to dismantle D-loops supports the role of this enzyme in preventing recombination between short repeats. Our results suggest that plant organelles have evolved novel DNA repair routes centered around the anti-recombinogenic activity of MSH1.
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Affiliation(s)
- Alejandro Peñafiel-Ayala
- Langebio-Cinvestav Sede Irapuato, Km. 9.6 Libramiento Norte Carretera. Irapuato-León, Irapuato, Guanajuato 36821, México
| | - Antolin Peralta-Castro
- Langebio-Cinvestav Sede Irapuato, Km. 9.6 Libramiento Norte Carretera. Irapuato-León, Irapuato, Guanajuato 36821, México
| | - Josue Mora-Garduño
- Langebio-Cinvestav Sede Irapuato, Km. 9.6 Libramiento Norte Carretera. Irapuato-León, Irapuato, Guanajuato 36821, México
| | - Paola García-Medel
- Langebio-Cinvestav Sede Irapuato, Km. 9.6 Libramiento Norte Carretera. Irapuato-León, Irapuato, Guanajuato 36821, México
| | - Angie G Zambrano-Pereira
- Langebio-Cinvestav Sede Irapuato, Km. 9.6 Libramiento Norte Carretera. Irapuato-León, Irapuato, Guanajuato 36821, México
| | - Corina Díaz-Quezada
- Langebio-Cinvestav Sede Irapuato, Km. 9.6 Libramiento Norte Carretera. Irapuato-León, Irapuato, Guanajuato 36821, México
| | - María Jazmín Abraham-Juárez
- Langebio-Cinvestav Sede Irapuato, Km. 9.6 Libramiento Norte Carretera. Irapuato-León, Irapuato, Guanajuato 36821, México
| | - Claudia G Benítez-Cardoza
- Laboratorio de Investigación Bioquímica, Programa Institucional en Biomedicina Molecular ENMyH-IPN, Guillermo Massieu Helguera No. 239, La Escalera Ticoman 07320 DF, México
| | - Daniel B Sloan
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Luis G Brieba
- Langebio-Cinvestav Sede Irapuato, Km. 9.6 Libramiento Norte Carretera. Irapuato-León, Irapuato, Guanajuato 36821, México
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2
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Borsellini A, Kunetsky V, Friedhoff P, Lamers MH. Cryogenic electron microscopy structures reveal how ATP and DNA binding in MutS coordinates sequential steps of DNA mismatch repair. Nat Struct Mol Biol 2022; 29:59-66. [PMID: 35013597 DOI: 10.1038/s41594-021-00707-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 11/24/2021] [Indexed: 12/18/2022]
Abstract
DNA mismatch repair detects and corrects mismatches introduced during DNA replication. The protein MutS scans for mismatches and coordinates the repair cascade. During this process, MutS undergoes multiple conformational changes in response to ATP binding, hydrolysis and release, but how ATP induces the various MutS conformations is incompletely understood. Here we present four cryogenic electron microscopy structures of Escherichia coli MutS at sequential stages of the ATP hydrolysis cycle that reveal how ATP binding and hydrolysis induce closing and opening of the MutS dimer, respectively. Biophysical analysis demonstrates how DNA binding modulates the ATPase cycle by prevention of hydrolysis during scanning and mismatch binding, while preventing ADP release in the sliding clamp state. Nucleotide release is achieved when MutS encounters single-stranded DNA that is produced during removal of the daughter strand. The combination of ATP binding and hydrolysis and its modulation by DNA enables MutS to adopt the different conformations needed to coordinate the sequential steps of the mismatch repair cascade.
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Affiliation(s)
- Alessandro Borsellini
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, the Netherlands
| | | | - Peter Friedhoff
- Institute for Biochemistry, Justus-Liebig University, Giessen, Germany
| | - Meindert H Lamers
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, the Netherlands.
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3
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Inoue K, Takada S, Terakawa T. Coarse-grained molecular dynamics simulations of base-pair mismatch recognition protein MutS sliding along DNA. Biophys Physicobiol 2022; 19:1-16. [PMID: 35797408 PMCID: PMC9173861 DOI: 10.2142/biophysico.bppb-v19.0015] [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: 03/15/2022] [Accepted: 04/12/2022] [Indexed: 12/01/2022] Open
Abstract
DNA mismatches are frequently generated by various intrinsic and extrinsic factors including DNA replication errors, oxygen species, ultraviolet, and ionizing radiation. These mismatches should be corrected by the mismatches repair (MMR) pathway to maintain genome integrity. In the Escherichia coli (E. coli) MMR pathway, MutS searches and recognizes a base-pair mismatch from millions of base-pairs. Once recognized, ADP bound to MutS is exchanged with ATP, which induces a conformational change in MutS. Previous single-molecule fluorescence microscopy studies have suggested that ADP-bound MutS temporarily slides along double-stranded DNA in a rotation-coupled manner to search a base-pair mismatch and so does ATP-bound MutS in a rotation-uncoupled manner. However, the detailed structural dynamics of the sliding remains unclear. In this study, we performed coarse-grained molecular dynamics simulations of the E. coli MutS bound on DNA in three different conformations: ADP-bound (MutSADP), ATP-bound open clamp (MutSOpenATP), and ATP-bound closed clamp (MutSClosedATP) conformations. In the simulations, we observed conformation-dependent diffusion of MutS along DNA. MutSADP and MutSClosedATP diffused along DNA in a rotation-coupled manner with rare and frequent groove-crossing events, respectively. In the groove-crossing events, MutS overcame an edge of a groove and temporarily diffused in a rotation-uncoupled manner. It was also indicated that mismatch searches by MutSOpenATP is inefficient in terms of mismatch checking even though it diffuses along DNA and reaches unchecked regions more rapidly than MutSADP.
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Affiliation(s)
- Keisuke Inoue
- Department of Biophysics, Graduate School of Science, Kyoto University
| | - Shoji Takada
- Department of Biophysics, Graduate School of Science, Kyoto University
| | - Tsuyoshi Terakawa
- Department of Biophysics, Graduate School of Science, Kyoto University
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4
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Large conformational changes in MutS during DNA scanning, mismatch recognition and repair signalling. EMBO J 2012; 31:2528-40. [PMID: 22505031 DOI: 10.1038/emboj.2012.95] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Accepted: 03/21/2012] [Indexed: 12/18/2022] Open
Abstract
MutS protein recognizes mispaired bases in DNA and targets them for mismatch repair. Little is known about the transient conformations of MutS as it signals initiation of repair. We have used single-molecule fluorescence resonance energy transfer (FRET) measurements to report the conformational dynamics of MutS during this process. We find that the DNA-binding domains of MutS dynamically interconvert among multiple conformations when the protein is free and while it scans homoduplex DNA. Mismatch recognition restricts MutS conformation to a single state. Steady-state measurements in the presence of nucleotides suggest that both ATP and ADP must be bound to MutS during its conversion to a sliding clamp form that signals repair. The transition from mismatch recognition to the sliding clamp occurs via two sequential conformational changes. These intermediate conformations of the MutS:DNA complex persist for seconds, providing ample opportunity for interaction with downstream proteins required for repair.
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5
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Inactivation of the DNA repair genes mutS, mutL or the anti-recombination gene mutS2 leads to activation of vitamin B1 biosynthesis genes. PLoS One 2011; 6:e19053. [PMID: 21552516 PMCID: PMC3084264 DOI: 10.1371/journal.pone.0019053] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Accepted: 03/22/2011] [Indexed: 11/20/2022] Open
Abstract
Oxidative stress generates harmful reactive oxygen species (ROS) that attack biomolecules including DNA. In living cells, there are several mechanisms for detoxifying ROS and repairing oxidatively-damaged DNA. In this study, transcriptomic analyses clarified that disruption of DNA repair genes mutS and mutL, or the anti-recombination gene mutS2, in Thermus thermophilus HB8, induces the biosynthesis pathway for vitamin B1, which can serve as an ROS scavenger. In addition, disruption of mutS, mutL, or mutS2 resulted in an increased rate of oxidative stress-induced mutagenesis. Co-immunoprecipitation and pull-down experiments revealed previously-unknown interactions of MutS2 with MutS and MutL, indicating that these proteins cooperatively participate in the repair of oxidatively damaged DNA. These results suggested that bacterial cells sense the accumulation of oxidative DNA damage or absence of DNA repair activity, and signal the information to the transcriptional regulation machinery for an ROS-detoxifying system.
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6
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Winkler I, Marx AD, Lariviere D, Heinze RJ, Cristovao M, Reumer A, Curth U, Sixma TK, Friedhoff P. Chemical trapping of the dynamic MutS-MutL complex formed in DNA mismatch repair in Escherichia coli. J Biol Chem 2011; 286:17326-37. [PMID: 21454657 DOI: 10.1074/jbc.m110.187641] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The ternary complex comprising MutS, MutL, and DNA is a key intermediate in DNA mismatch repair. We used chemical cross-linking and fluorescence resonance energy transfer (FRET) to study the interaction between MutS and MutL and to shed light onto the structure of this complex. Via chemical cross-linking, we could stabilize this dynamic complex and identify the structural features of key events in DNA mismatch repair. We could show that in the complex between MutS and MutL the mismatch-binding and connector domains of MutS are in proximity to the N-terminal ATPase domain of MutL. The DNA- and nucleotide-dependent complex formation could be monitored by FRET using single cysteine variants labeled in the connector domain of MutS and the transducer domain of MutL, respectively. In addition, we could trap MutS after an ATP-induced conformational change by an intramolecular cross-link between Cys-93 of the mismatch-binding domain and Cys-239 of the connector domain.
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Affiliation(s)
- Ines Winkler
- Institute for Biochemistry, FB 08, Justus Liebig University, D-35392 Giessen, Germany
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7
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Morita R, Nakane S, Shimada A, Inoue M, Iino H, Wakamatsu T, Fukui K, Nakagawa N, Masui R, Kuramitsu S. Molecular mechanisms of the whole DNA repair system: a comparison of bacterial and eukaryotic systems. J Nucleic Acids 2010; 2010:179594. [PMID: 20981145 PMCID: PMC2957137 DOI: 10.4061/2010/179594] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Accepted: 07/27/2010] [Indexed: 11/20/2022] Open
Abstract
DNA is subjected to many endogenous and exogenous damages. All organisms have developed a complex network of DNA repair mechanisms. A variety of different DNA repair pathways have been reported: direct reversal, base excision repair, nucleotide excision repair, mismatch repair, and recombination repair pathways. Recent studies of the fundamental mechanisms for DNA repair processes have revealed a complexity beyond that initially expected, with inter- and intrapathway complementation as well as functional interactions between proteins involved in repair pathways. In this paper we give a broad overview of the whole DNA repair system and focus on the molecular basis of the repair machineries, particularly in Thermus thermophilus HB8.
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Affiliation(s)
- Rihito Morita
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
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8
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Fukui K. DNA mismatch repair in eukaryotes and bacteria. J Nucleic Acids 2010; 2010. [PMID: 20725617 PMCID: PMC2915661 DOI: 10.4061/2010/260512] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2010] [Accepted: 06/24/2010] [Indexed: 12/17/2022] Open
Abstract
DNA mismatch repair (MMR) corrects mismatched base pairs mainly caused by DNA replication errors. The fundamental mechanisms and proteins involved in the early reactions of MMR are highly conserved in almost all organisms ranging from bacteria to human. The significance of this repair system is also indicated by the fact that defects in MMR cause human hereditary nonpolyposis colon cancers as well as sporadic tumors. To date, 2 types of MMRs are known: the human type and Escherichia coli type. The basic features of the former system are expected to be universal among the vast majority of organisms including most bacteria. Here, I review the molecular mechanisms of eukaryotic and bacterial MMR, emphasizing on the similarities between them.
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Affiliation(s)
- Kenji Fukui
- RIKEN SPring-8 Center, Harima Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
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9
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Mukherjee S, Feig M. Conformational change in MSH2-MSH6 upon binding DNA coupled to ATPase activity. Biophys J 2009; 96:L63-5. [PMID: 19486659 DOI: 10.1016/j.bpj.2009.04.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2009] [Revised: 03/30/2009] [Accepted: 04/08/2009] [Indexed: 01/18/2023] Open
Abstract
Postreplication DNA mismatch repair is initiated by the eukaryotic protein MSH2-MSH6 or the prokaryotic protein MutS, both showing overall conserved structure and functionality. Crystal structures of MSH2-MSH6 and MutS bound to the mismatch DNA reveal a closed architecture of the clamp and the lever domains exhibiting strong contacts with the bent DNA backbone. Long molecular dynamics simulations of the human MSH2-MSH6 protein in the absence of a DNA show an altered conformation of the protein that reflects the protein's state before binding to DNA. The clamp and the lever domains of both MSH6 and MSH2 open in an asymmetric and dramatic fashion. The opening of the clamp and the lever domains in the absence of DNA is coupled to changes in the ATPase domains, which explains the experimentally observed diminished ATPase activity in DNA-free MSH2-MSH6 and illustrates the allosteric coupling between DNA binding and ATPase activity.
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Affiliation(s)
- Shayantani Mukherjee
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
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10
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Mukherjee S, Law SM, Feig M. Deciphering the mismatch recognition cycle in MutS and MSH2-MSH6 using normal-mode analysis. Biophys J 2009; 96:1707-20. [PMID: 19254532 DOI: 10.1016/j.bpj.2008.10.071] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Accepted: 10/24/2008] [Indexed: 11/24/2022] Open
Abstract
Postreplication DNA mismatch repair is essential for maintaining the integrity of genomic information in prokaryotes and eukaryotes. The first step in mismatch repair is the recognition of base-base mismatches and insertions/deletions by bacterial MutS or eukaryotic MSH2-MSH6. Crystal structures of both proteins bound to mismatch DNA reveal a similar molecular architecture but provide limited insight into the detailed molecular mechanism of long-range allostery involved in mismatch recognition and repair initiation. This study describes normal-mode calculations of MutS and MSH2-MSH6 with and without DNA. The results reveal similar protein flexibilities and suggest common dynamic and functional characteristics. A strongly correlated motion is present between the lever domain and ATPase domains, which suggests a pathway for long-range allostery from the N-terminal DNA binding domain to the C-terminal ATPase domains, as indicated by experimental studies. A detailed analysis of individual low-frequency modes of both MutS and MSH2-MSH6 shows changes in the DNA-binding domains coupled to the ATPase sites, which are interpreted in the context of experimental data to arrive at a complete molecular-level mismatch recognition cycle. Distinct conformational states are proposed for DNA scanning, mismatch recognition, repair initiation, and sliding along DNA after mismatch recognition. Hypotheses based on the results presented here form the basis for further experimental and computational studies.
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Affiliation(s)
- Shayantani Mukherjee
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
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11
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Kamikubo H, Shimizu N, Harigai M, Yamazaki Y, Imamoto Y, Kataoka M. Characterization of the solution structure of the M intermediate of photoactive yellow protein using high-angle solution x-ray scattering. Biophys J 2007; 92:3633-42. [PMID: 17307829 PMCID: PMC1853148 DOI: 10.1529/biophysj.106.097287] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
It is widely accepted that PYP undergoes global structural changes during the formation of the biologically active intermediate PYP(M). High-angle solution x-ray scattering experiments were performed using PYP variants that lacked the N-terminal 6-, 15-, or 23-amino-acid residues (T6, T15, and T23, respectively) to clarify these structural changes. The scattering profile of the dark state of intact PYP exhibited two broad peaks in the high-angle region (0.3 A(-1) < Q < 0.8 A(-1)). The intensities and positions of the peaks were systematically changed as a result of the N-terminal truncations. These observations and the agreement between the observed scattering profiles and the calculated profiles based on the crystal structure confirm that the high-angle scattering profiles were caused by intramolecular interference and that the structure of the chromophore-binding domain was not affected by the N-terminal truncations. The profiles of the PYP(M) intermediates of the N-terminally truncated PYP variants were significantly different from the profiles of the dark states of these proteins, indicating that substantial conformational rearrangements occur within the chromophore-binding domain during the formation of PYP(M). By use of molecular fluctuation analysis, structural models of the chromophore-binding region of PYP(M) were constructed to reproduce the observed profile of T23. The structure obtained by averaging 51 potential models revealed the displacement of the loop connecting beta4 and beta5, and the deformation of the alpha4 helix. High-angle x-ray scattering with molecular fluctuation simulation allows us to derive the structural properties of the transient state of a protein in solution.
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Affiliation(s)
- Hironari Kamikubo
- Graduate School of Materials Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
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12
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Fukui K, Kosaka H, Kuramitsu S, Masui R. Nuclease activity of the MutS homologue MutS2 from Thermus thermophilus is confined to the Smr domain. Nucleic Acids Res 2007; 35:850-60. [PMID: 17215294 PMCID: PMC1807967 DOI: 10.1093/nar/gkl735] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
MutS homologues are highly conserved enzymes engaged in DNA mismatch repair (MMR), meiotic recombination and other DNA modifications. Genome sequencing projects have revealed that bacteria and plants possess a MutS homologue, MutS2. MutS2 lacks the mismatch-recognition domain of MutS, but contains an extra C-terminal region called the small MutS-related (Smr) domain. Sequences homologous to the Smr domain are annotated as ‘proteins of unknown function’ in various organisms ranging from bacteria to human. Although recent in vivo studies indicate that MutS2 plays an important role in recombinational events, there had been only limited characterization of the biochemical function of MutS2 and the Smr domain. We previously established that Thermus thermophilus MutS2 (ttMutS2) possesses endonuclease activity. In this study, we report that a Smr-deleted ttMutS2 mutant retains the dimerization, ATPase and DNA-binding activities, but has no endonuclease activity. Furthermore, the Smr domain alone was stable and functional in binding and incising DNA. It is noteworthy that an endonuclease activity is associated with a MutS homologue, which is generally thought to recognize specific DNA structures.
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Affiliation(s)
- Kenji Fukui
- Department of Biological Sciences, Graduate School of Science, Osaka UniversityToyonaka, Osaka 560-0043, Japan
| | - Hiromichi Kosaka
- Department of Biological Sciences, Graduate School of Science, Osaka UniversityToyonaka, Osaka 560-0043, Japan
| | - Seiki Kuramitsu
- Department of Biological Sciences, Graduate School of Science, Osaka UniversityToyonaka, Osaka 560-0043, Japan
- RIKEN SPring-8 Center, Harima Institute1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - Ryoji Masui
- Department of Biological Sciences, Graduate School of Science, Osaka UniversityToyonaka, Osaka 560-0043, Japan
- RIKEN SPring-8 Center, Harima Institute1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
- To whom correspondence should be addressed at Department of Biology, Graduate School of Science, Osaka University, 1-1 Machikaneyamacho, Toyonaka, Osaka 560-0043, Japan. Tel: +81 06 6850 5433; Fax: +81 06 6850 5442;
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13
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Joseph N, Duppatla V, Rao DN. Functional characterization of the DNA mismatch binding protein MutS from Haemophilus influenzae. Biochem Biophys Res Commun 2006; 334:891-900. [PMID: 16026761 DOI: 10.1016/j.bbrc.2005.06.178] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2005] [Accepted: 06/29/2005] [Indexed: 10/25/2022]
Abstract
This investigation demonstrates DNA mismatch repair activity in Haemophilus influenzae cell free extracts. The mutS gene as well as purified protein of H. influenzae restored repair activity in complementation assays performed with mutS deficient Escherichia coli strain. The difference in affinity for GT and AC mismatched bases by H. influenzae MutS was reflected in the efficiency with which these DNA heteroduplexes were repaired in vitro, with GT being repaired well and AC the least. Unlike E. coli MutS, the H. influenzae homolog failed to give protein-DNA complex with homoduplex DNA. Interestingly, MutS was found to bind single-stranded DNA but with lesser affinity as compared to heteroduplex DNA. Apart from the nucleotide- and DNA-mediated conformational transitions, as monitored by circular dichroism and limited proteolysis, our data suggest a functional role when H. influenzae MutS encounters single-stranded DNA during exonucleolytic step of DNA repair process. We propose that, conformational changes in H. influenzae MutS not only modulate mismatch recognition but also trigger some of the down stream processes involved in the DNA mismatch repair process.
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Affiliation(s)
- Nimesh Joseph
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India
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14
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Joseph N, Duppatla V, Rao DN. Prokaryotic DNA Mismatch Repair. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 2006; 81:1-49. [PMID: 16891168 DOI: 10.1016/s0079-6603(06)81001-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Nimesh Joseph
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
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15
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Abstract
DNA mismatch repair (MMR) is an evolutionarily conserved process that corrects mismatches generated during DNA replication and escape proofreading. MMR proteins also participate in many other DNA transactions, such that inactivation of MMR can have wide-ranging biological consequences, which can be either beneficial or detrimental. We begin this review by briefly considering the multiple functions of MMR proteins and the consequences of impaired function. We then focus on the biochemical mechanism of MMR replication errors. Emphasis is on structure-function studies of MMR proteins, on how mismatches are recognized, on the process by which the newly replicated strand is identified, and on excision of the replication error.
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Affiliation(s)
- Thomas A Kunkel
- Laboratory of Molecular Genetics and Laboratory of Structural Biology, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA.
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16
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Antony E, Hingorani MM. Asymmetric ATP binding and hydrolysis activity of the Thermus aquaticus MutS dimer is key to modulation of its interactions with mismatched DNA. Biochemistry 2004; 43:13115-28. [PMID: 15476405 PMCID: PMC2839884 DOI: 10.1021/bi049010t] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Prokaryotic MutS and eukaryotic Msh proteins recognize base pair mismatches and insertions or deletions in DNA and initiate mismatch repair. These proteins function as dimers (and perhaps higher order oligomers) and possess an ATPase activity that is essential for DNA repair. Previous studies of Escherichia coli MutS and eukaryotic Msh2-Msh6 proteins have revealed asymmetry within the dimer with respect to both DNA binding and ATPase activities. We have found the Thermus aquaticus MutS protein amenable to detailed investigation of the nature and role of this asymmetry. Here, we show that (a) in a MutS dimer one subunit (S1) binds nucleotide with high affinity and the other (S2) with 10-fold weaker affinity, (b) S1 hydrolyzes ATP rapidly while S2 hydrolyzes ATP at a 30-50-fold slower rate, (c) mismatched DNA binding to MutS inhibits ATP hydrolysis at S1 but slow hydrolysis continues at S2, and (d) interaction between mismatched DNA and MutS is weakened when both subunits are occupied by ATP but remains stable when S1 is occupied by ATP and S2 by ADP. These results reveal key MutS species in the ATPase pathway; S1(ADP)-S2(ATP) is formed preferentially in the absence of DNA or in the presence of fully matched DNA, while S1(ATP)-S2(ATP) and S1(ATP)-S2(ADP) are formed preferentially in the presence of mismatched DNA. These MutS species exhibit differences in interaction with mismatched DNA that are likely important for the mechanism of MutS action in DNA repair.
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17
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Lamers MH, Georgijevic D, Lebbink JH, Winterwerp HHK, Agianian B, de Wind N, Sixma TK. ATP increases the affinity between MutS ATPase domains. Implications for ATP hydrolysis and conformational changes. J Biol Chem 2004; 279:43879-85. [PMID: 15297450 DOI: 10.1074/jbc.m406380200] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
MutS is the key protein of the Escherichia coli DNA mismatch repair system. It recognizes mispaired and unpaired bases and has intrinsic ATPase activity. ATP binding after mismatch recognition by MutS serves as a switch that enables MutL binding and the subsequent initiation of mismatch repair. However, the mechanism of this switch is poorly understood. We have investigated the effects of ATP binding on the MutS structure. Crystallographic studies of ATP-soaked crystals of MutS show a trapped intermediate, with ATP in the nucleotide-binding site. Local rearrangements of several residues around the nucleotide-binding site suggest a movement of the two ATPase domains of the MutS dimer toward each other. Analytical ultracentrifugation experiments confirm such a rearrangement, showing increased affinity between the ATPase domains upon ATP binding and decreased affinity in the presence of ADP. Mutations of specific residues in the nucleotide-binding domain reduce the dimer affinity of the ATPase domains. In addition, ATP-induced release of DNA is strongly reduced in these mutants, suggesting that the two activities are coupled. Hence, it seems plausible that modulation of the affinity between ATPase domains is the driving force for conformational changes in the MutS dimer. These changes are driven by distinct amino acids in the nucleotide-binding site and form the basis for long-range interactions between the ATPase domains and DNA-binding domains and subsequent binding of MutL and initiation of mismatch repair.
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Affiliation(s)
- Meindert H Lamers
- Division of Molecular Carcinogenesis, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam
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Joshi A, Rao BJ. ATP hydrolysis induces expansion of MutS contacts on heteroduplex: a case for MutS treadmilling? Biochemistry 2002; 41:3654-66. [PMID: 11888282 DOI: 10.1021/bi015743r] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An unsolved problem in E. coli mismatch repair is how the MutS-MutL complex communicates positional information of a mismatch to MutH. MutS is bound to a mismatch in the absence of ATP, exhibiting a short DNase I footprint that is dramatically expanded in ATP hydrolysis. The same is corroborated by restriction enzyme site protection far away from the mismatch. High-resolution gel-shift analyses revealed that super-shifted specific complexes, presumably containing multiple MutS homodimers on the same heteroduplex, were generated during ATP hydrolysis. Such complexes are largely nonspecific in "minus ATP" or in ATP gamma S conditions. Specific ternary complexes of MutS-MutL-heteroduplexes were formed only during ATP hydrolysis. These results suggest that MutS loading onto a mismatch induces the formation of a higher-order complex containing multiple MutS homodimers, presumably through a putative "treadmilling action" that is ATP-hydrolysis dependent. Such a higher-order MutS complex productively interacts with MutL in ATP-hydrolyzing conditions and generates a specific ternary complex, which might communicate with MutH. This model should neither depend on nor give rise to the spooling of DNA. This was corroborated when we observed footprint extension in ATP-hydrolyzing conditions, despite the heteroduplex ends being tethered to agarose beads that block helical rotations.
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Affiliation(s)
- Amita Joshi
- Department of Biological Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Bombay 400 005, India
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