1
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Jayaraj A, Thayer KM, Beveridge DL, Hingorani MM. Molecular dynamics of mismatch detection-How MutS uses indirect readout to find errors in DNA. Biophys J 2023; 122:3031-3043. [PMID: 37329136 PMCID: PMC10432192 DOI: 10.1016/j.bpj.2023.06.006] [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: 07/05/2022] [Revised: 04/30/2023] [Accepted: 06/12/2023] [Indexed: 06/18/2023] Open
Abstract
The mismatch repair protein MutS safeguards genomic integrity by finding and initiating repair of basepairing errors in DNA. Single-molecule studies show MutS diffusing on DNA, presumably scanning for mispaired/unpaired bases, and crystal structures show a characteristic "mismatch-recognition" complex with DNA enclosed within MutS and kinked at the site of error. But how MutS goes from scanning thousands of Watson-Crick basepairs to recognizing rare mismatches remains unanswered, largely because atomic-resolution data on the search process are lacking. Here, 10 μs all-atom molecular dynamics simulations of Thermus aquaticus MutS bound to homoduplex DNA and T-bulge DNA illuminate the structural dynamics underlying the search mechanism. MutS-DNA interactions constitute a multistep mechanism to check DNA over two helical turns for its 1) shape, through contacts with the sugar-phosphate backbone, 2) conformational flexibility, through bending/unbending engineered by large-scale motions of the clamp domain, and 3) local deformability, through basepair destabilizing contacts. Thus, MutS can localize a potential target by indirect readout due to lower energetic costs of bending mismatched DNA and identify a site that distorts easily due to weaker base stacking and pairing as a mismatch. The MutS signature Phe-X-Glu motif can then lock in the mismatch-recognition complex to initiate repair.
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Affiliation(s)
- Abhilash Jayaraj
- Chemistry Department, Wesleyan University, Middletown, Connecticut.
| | - Kelly M Thayer
- Chemistry Department, Wesleyan University, Middletown, Connecticut
| | | | - Manju M Hingorani
- Molecular Biology and Biochemistry Department, Wesleyan University, Middletown, Connecticut.
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2
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Bruekner SR, Pieters W, Fish A, Liaci AM, Scheffers S, Rayner E, Kaldenbach D, Drost L, Dekker M, van Hees-Stuivenberg S, Delzenne-Goette E, de Konink C, Houlleberghs H, Dubbink H, AlSaegh A, de Wind N, Förster F, te Riele H, Sixma T. Unexpected moves: a conformational change in MutSα enables high-affinity DNA mismatch binding. Nucleic Acids Res 2023; 51:1173-1188. [PMID: 36715327 PMCID: PMC9943660 DOI: 10.1093/nar/gkad015] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 12/30/2022] [Accepted: 01/12/2023] [Indexed: 01/31/2023] Open
Abstract
The DNA mismatch repair protein MutSα recognizes wrongly incorporated DNA bases and initiates their correction during DNA replication. Dysfunctions in mismatch repair lead to a predisposition to cancer. Here, we study the homozygous mutation V63E in MSH2 that was found in the germline of a patient with suspected constitutional mismatch repair deficiency syndrome who developed colorectal cancer before the age of 30. Characterization of the mutant in mouse models, as well as slippage and repair assays, shows a mildly pathogenic phenotype. Using cryogenic electron microscopy and surface plasmon resonance, we explored the mechanistic effect of this mutation on MutSα function. We discovered that V63E disrupts a previously unappreciated interface between the mismatch binding domains (MBDs) of MSH2 and MSH6 and leads to reduced DNA binding. Our research identifies this interface as a 'safety lock' that ensures high-affinity DNA binding to increase replication fidelity. Our mechanistic model explains the hypomorphic phenotype of the V63E patient mutation and other variants in the MBD interface.
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Affiliation(s)
| | | | - Alexander Fish
- Division of Biochemistry, Netherlands Cancer Institute and Oncode Institute, 1066 CX Amsterdam, The Netherlands
| | - A Manuel Liaci
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584CH Utrecht, The Netherlands
| | - Serge Scheffers
- Division of Biochemistry, Netherlands Cancer Institute and Oncode Institute, 1066 CX Amsterdam, The Netherlands
| | - Emily Rayner
- Department of Human Genetics, Leiden University Medical Center, PO Box 9600 2300RC Leiden, The Netherlands
| | - Daphne Kaldenbach
- Division of Tumor Biology and Immunology, Netherlands Cancer Institute, 1066CX Amsterdam, The Netherlands
| | - Lisa Drost
- Division of Tumor Biology and Immunology, Netherlands Cancer Institute, 1066CX Amsterdam, The Netherlands
| | - Marleen Dekker
- Division of Tumor Biology and Immunology, Netherlands Cancer Institute, 1066CX Amsterdam, The Netherlands
| | | | - Elly Delzenne-Goette
- Division of Tumor Biology and Immunology, Netherlands Cancer Institute, 1066CX Amsterdam, The Netherlands
| | - Charlotte de Konink
- Division of Tumor Biology and Immunology, Netherlands Cancer Institute, 1066CX Amsterdam, The Netherlands
| | - Hellen Houlleberghs
- Division of Tumor Biology and Immunology, Netherlands Cancer Institute, 1066CX Amsterdam, The Netherlands
| | - Hendrikus Jan Dubbink
- Department of Pathology, Erasmus Medical Center, PO Box 2040 3000CA Rotterdam, The Netherlands
| | - Abeer AlSaegh
- Sultan Qaboos Comprehensive Cancer Care and Research Center, PO Box 787, 117 Muscat, Oman
| | - Niels de Wind
- Department of Human Genetics, Leiden University Medical Center, PO Box 9600 2300RC Leiden, The Netherlands
| | - Friedrich Förster
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584CH Utrecht, The Netherlands
| | - Hein te Riele
- Correspondence may also be addressed to Hein te Riele. Tel: +31 20 512 2084;
| | - Titia K Sixma
- To whom correspondence should be addressed: Tel: +31 20 512 1959;
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3
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MutS recognition of mismatches within primed DNA replication intermediates. DNA Repair (Amst) 2022; 119:103392. [PMID: 36095926 DOI: 10.1016/j.dnarep.2022.103392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 08/23/2022] [Accepted: 08/25/2022] [Indexed: 11/24/2022]
Abstract
MutS initiates mismatch repair by recognizing mismatches in newly replicated DNA. Specific interactions between MutS and mismatches within double-stranded DNA promote ADP-ATP exchange and a conformational change into a sliding clamp. Here, we demonstrated that MutS from Pseudomonas aeruginosa associates with primed DNA replication intermediates. The predicted structure of this MutS-DNA complex revealed a new DNA binding site, in which Asn 279 and Arg 272 appeared to directly interact with the 3'-OH terminus of primed DNA. Mutation of these residues resulted in a noticeable defect in the interaction of MutS with primed DNA substrates. Remarkably, MutS interaction with a mismatch within primed DNA induced a compaction of the protein structure and impaired the formation of an ATP-bound sliding clamp. Our findings reveal a novel DNA binding mode, conformational change and intramolecular signaling for MutS recognition of mismatches within primed DNA structures.
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4
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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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5
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Ngo LT, Wang WK, Tseng YT, Chang TC, Kuo PL, Chau LK, Huang TT. MutS protein-based fiber optic particle plasmon resonance biosensor for detecting single nucleotide polymorphisms. Anal Bioanal Chem 2021; 413:3329-3337. [PMID: 33712917 DOI: 10.1007/s00216-021-03271-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 02/08/2021] [Accepted: 03/04/2021] [Indexed: 01/29/2023]
Abstract
A new biosensing method is presented to detect gene mutation by integrating the MutS protein from bacteria with a fiber optic particle plasmon resonance (FOPPR) sensing system. In this method, the MutS protein is conjugated with gold nanoparticles (AuNPs) deposited on an optical fiber core surface. The target double-stranded DNA containing an A and C mismatched base pair in a sample can be captured by the MutS protein, causing increased absorption of green light launching into the fiber and hence a decrease in transmitted light intensity through the fiber. As the signal change is enhanced through consecutive total internal reflections along the fiber, the limit of detection for an AC mismatch heteroduplex DNA can be as low as 0.49 nM. Because a microfluidic chip is used to contain the optical fiber, the narrow channel width allows an analysis time as short as 15 min. Furthermore, the label-free and real-time nature of the FOPPR sensing system enables determination of binding affinity and kinetics between MutS and single-base mismatched DNA. The method has been validated using a heterozygous PCR sample from a patient to determine the allelic fraction. The obtained allelic fraction of 0.474 reasonably agrees with the expected allelic fraction of 0.5. Therefore, the MutS-functionalized FOPPR sensor may potentially provide a convenient quantitative tool to detect single nucleotide polymorphisms in biological samples with a short analysis time at the point-of-care sites.
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Affiliation(s)
- Loan Thi Ngo
- Department of Chemistry and Biochemistry and Center for Nano Bio-Detection, National Chung Cheng University, Chiayi, 62102, Taiwan
| | - Wei-Kai Wang
- Department of Dentistry, Institute of Oral Medicine, Department of Stomatology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, 70101, Taiwan
| | - Yen-Ta Tseng
- Department of Chemistry and Biochemistry and Center for Nano Bio-Detection, National Chung Cheng University, Chiayi, 62102, Taiwan
| | - Ting-Chou Chang
- Department of Chemistry and Biochemistry and Center for Nano Bio-Detection, National Chung Cheng University, Chiayi, 62102, Taiwan
| | - Pao-Lin Kuo
- Department of Obstetrics Gynecology, National Cheng Kung University Hospital, College of Medicine and Hospital, National Cheng Kung University, Tainan, 70101, Taiwan
| | - Lai-Kwan Chau
- Department of Chemistry and Biochemistry and Center for Nano Bio-Detection, National Chung Cheng University, Chiayi, 62102, Taiwan.
| | - Tze-Ta Huang
- Department of Dentistry, Institute of Oral Medicine, Department of Stomatology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, 70101, Taiwan.
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6
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Recurrent mismatch binding by MutS mobile clamps on DNA localizes repair complexes nearby. Proc Natl Acad Sci U S A 2020; 117:17775-17784. [PMID: 32669440 DOI: 10.1073/pnas.1918517117] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
DNA mismatch repair (MMR), the guardian of the genome, commences when MutS identifies a mismatch and recruits MutL to nick the error-containing strand, allowing excision and DNA resynthesis. Dominant MMR models posit that after mismatch recognition, ATP converts MutS to a hydrolysis-independent, diffusive mobile clamp that no longer recognizes the mismatch. Little is known about the postrecognition MutS mobile clamp and its interactions with MutL. Two disparate frameworks have been proposed: One in which MutS-MutL complexes remain mobile on the DNA, and one in which MutL stops MutS movement. Here we use single-molecule FRET to follow the postrecognition states of MutS and the impact of MutL on its properties. In contrast to current thinking, we find that after the initial mobile clamp formation event, MutS undergoes frequent cycles of mismatch rebinding and mobile clamp reformation without releasing DNA. Notably, ATP hydrolysis is required to alter the conformation of MutS such that it can recognize the mismatch again instead of bypassing it; thus, ATP hydrolysis licenses the MutS mobile clamp to rebind the mismatch. Moreover, interaction with MutL can both trap MutS at the mismatch en route to mobile clamp formation and stop movement of the mobile clamp on DNA. MutS's frequent rebinding of the mismatch, which increases its residence time in the vicinity of the mismatch, coupled with MutL's ability to trap MutS, should increase the probability that MutS-MutL MMR initiation complexes localize near the mismatch.
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7
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Probing the DNA-binding center of the MutL protein from the Escherichia coli mismatch repair system via crosslinking and Förster resonance energy transfer. Biochimie 2020; 171-172:43-54. [PMID: 32061805 DOI: 10.1016/j.biochi.2020.02.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 02/11/2020] [Indexed: 11/23/2022]
Abstract
As no crystal structure of full-size MutL bound to DNA has been obtained up to date, in the present work we used crosslinking and Förster resonance energy transfer (FRET) assays for probing the putative DNA-binding center of MutL from Escherichia coli. Several single-cysteine MutL variants (scMutL) were used for site-specific crosslinking or fluorophore modification. The crosslinking efficiency between scMutL proteins and mismatched DNA modified with thiol-reactive probes correlated with the distances from the Cys residues to the DNA calculated from a model of MutS-MutL-DNA complex. FRET-based investigation of DNA binding with different scMutL variants clearly showed that the highest signals were detected for the variants MutL(T218C) and MutL(A251C) indicating closeness of the positions 218 and 251 to DNA in the MutL-DNA complex. Indeed, the Cys218 and Cys251 of scMutL were crosslinked to the reactive DNA with the highest yield demonstrating their proximity to DNA in the MutL-DNA complex. The presence of MutS increased the yield of conjugate formation between the MutL variants and the modified DNA due to tighter MutL-DNA interactions caused by MutS binding to MutL.
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8
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Sarangi MK, Zvoda V, Holte MN, Becker NA, Peters JP, Maher LJ, Ansari A. Evidence for a bind-then-bend mechanism for architectural DNA binding protein yNhp6A. Nucleic Acids Res 2019; 47:2871-2883. [PMID: 30698746 PMCID: PMC6451137 DOI: 10.1093/nar/gkz022] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 12/18/2018] [Accepted: 01/18/2019] [Indexed: 01/17/2023] Open
Abstract
The yeast Nhp6A protein (yNhp6A) is a member of the eukaryotic HMGB family of chromatin factors that enhance apparent DNA flexibility. yNhp6A binds DNA nonspecifically with nM affinity, sharply bending DNA by >60°. It is not known whether the protein binds to unbent DNA and then deforms it, or if bent DNA conformations are ‘captured’ by protein binding. The former mechanism would be supported by discovery of conditions where unbent DNA is bound by yNhp6A. Here, we employed an array of conformational probes (FRET, fluorescence anisotropy, and circular dichroism) to reveal solution conditions in which an 18-base-pair DNA oligomer indeed remains bound to yNhp6A while unbent. In 100 mM NaCl, yNhp6A-bound DNA unbends as the temperature is raised, with no significant dissociation of the complex detected up to ∼45°C. In 200 mM NaCl, DNA unbending in the intact yNhp6A complex is again detected up to ∼35°C. Microseconds-resolved laser temperature-jump perturbation of the yNhp6a–DNA complex revealed relaxation kinetics that yielded unimolecular DNA bending/unbending rates on timescales of 500 μs−1 ms. These data provide the first direct observation of bending/unbending dynamics of DNA in complex with yNhp6A, suggesting a bind-then-bend mechanism for this protein.
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Affiliation(s)
- Manas Kumar Sarangi
- Department of Physics, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Viktoriya Zvoda
- Department of Physics, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Molly Nelson Holte
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine and Science, Rochester, MN 55905, USA
| | - Nicole A Becker
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine and Science, Rochester, MN 55905, USA
| | - Justin P Peters
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine and Science, Rochester, MN 55905, USA
| | - L James Maher
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine and Science, Rochester, MN 55905, USA
| | - Anjum Ansari
- Department of Physics, University of Illinois at Chicago, Chicago, IL 60607, USA.,Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
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9
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LeBlanc SJ, Gauer JW, Hao P, Case BC, Hingorani MM, Weninger KR, Erie DA. Coordinated protein and DNA conformational changes govern mismatch repair initiation by MutS. Nucleic Acids Res 2019; 46:10782-10795. [PMID: 30272207 PMCID: PMC6237781 DOI: 10.1093/nar/gky865] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 09/26/2018] [Indexed: 12/13/2022] Open
Abstract
MutS homologs identify base-pairing errors made in DNA during replication and initiate their repair. In the presence of adenosine triphosphate, MutS induces DNA bending upon mismatch recognition and subsequently undergoes conformational transitions that promote its interaction with MutL to signal repair. In the absence of MutL, these transitions lead to formation of a MutS mobile clamp that can move along the DNA. Previous single-molecule FRET (smFRET) studies characterized the dynamics of MutS DNA-binding domains during these transitions. Here, we use protein–DNA and DNA–DNA smFRET to monitor DNA conformational changes, and we use kinetic analyses to correlate DNA and protein conformational changes to one another and to the steps on the pathway to mobile clamp formation. The results reveal multiple sequential structural changes in both MutS and DNA, and they suggest that DNA dynamics play a critical role in the formation of the MutS mobile clamp. Taking these findings together with data from our previous studies, we propose a unified model of coordinated MutS and DNA conformational changes wherein initiation of mismatch repair is governed by a balance of DNA bending/unbending energetics and MutS conformational changes coupled to its nucleotide binding properties.
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Affiliation(s)
- Sharonda J LeBlanc
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.,Department of Physics, North Carolina State University, Raleigh, NC 27695, USA
| | - Jacob W Gauer
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Pengyu Hao
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA
| | - Brandon C Case
- Molecular Biology and Biochemistry Department, Wesleyan University, Middletown, CT 06459, USA
| | - Manju M Hingorani
- Molecular Biology and Biochemistry Department, Wesleyan University, Middletown, CT 06459, USA
| | - Keith R Weninger
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA
| | - Dorothy A Erie
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.,Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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10
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Velmurugu Y, Vivas P, Connolly M, Kuznetsov SV, Rice PA, Ansari A. Two-step interrogation then recognition of DNA binding site by Integration Host Factor: an architectural DNA-bending protein. Nucleic Acids Res 2019; 46:1741-1755. [PMID: 29267885 PMCID: PMC5829579 DOI: 10.1093/nar/gkx1215] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 12/08/2017] [Indexed: 12/23/2022] Open
Abstract
The dynamics and mechanism of how site-specific DNA-bending proteins initially interrogate potential binding sites prior to recognition have remained elusive for most systems. Here we present these dynamics for Integration Host factor (IHF), a nucleoid-associated architectural protein, using a μs-resolved T-jump approach. Our studies show two distinct DNA-bending steps during site recognition by IHF. While the faster (∼100 μs) step is unaffected by changes in DNA or protein sequence that alter affinity by >100-fold, the slower (1–10 ms) step is accelerated ∼5-fold when mismatches are introduced at DNA sites that are sharply kinked in the specific complex. The amplitudes of the fast phase increase when the specific complex is destabilized and decrease with increasing [salt], which increases specificity. Taken together, these results indicate that the fast phase is non-specific DNA bending while the slow phase, which responds only to changes in DNA flexibility at the kink sites, is specific DNA kinking during site recognition. Notably, the timescales for the fast phase overlap with one-dimensional diffusion times measured for several proteins on DNA, suggesting that these dynamics reflect partial DNA bending during interrogation of potential binding sites by IHF as it scans DNA.
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Affiliation(s)
- Yogambigai Velmurugu
- Department of Physics, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Paula Vivas
- Department of Physics, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Mitchell Connolly
- Department of Physics, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Serguei V Kuznetsov
- Department of Physics, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Phoebe A Rice
- Department of Biochemistry & Molecular Biology, University of Chicago, Chicago, IL 60637, USA
| | - Anjum Ansari
- Department of Physics, University of Illinois at Chicago, Chicago, IL 60607, USA.,Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
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11
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Chakraborty S, Steinbach PJ, Paul D, Mu H, Broyde S, Min JH, Ansari A. Enhanced spontaneous DNA twisting/bending fluctuations unveiled by fluorescence lifetime distributions promote mismatch recognition by the Rad4 nucleotide excision repair complex. Nucleic Acids Res 2019; 46:1240-1255. [PMID: 29267981 PMCID: PMC5815138 DOI: 10.1093/nar/gkx1216] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 12/12/2017] [Indexed: 12/15/2022] Open
Abstract
Rad4/XPC recognizes diverse DNA lesions including ultraviolet-photolesions and carcinogen-DNA adducts, initiating nucleotide excision repair. Studies have suggested that Rad4/XPC senses lesion-induced helix-destabilization to flip out nucleotides from damaged DNA sites. However, characterizing how DNA deformability and/or distortions impact recognition has been challenging. Here, using fluorescence lifetime measurements empowered by a maximum entropy algorithm, we mapped the conformational heterogeneities of artificially destabilized mismatched DNA substrates of varying Rad4-binding specificities. The conformational distributions, as probed by FRET between a cytosine-analog pair exquisitely sensitive to DNA twisting/bending, reveal a direct connection between intrinsic DNA deformability and Rad4 recognition. High-specificity CCC/CCC mismatch, free in solution, sampled a strikingly broad range of conformations from B-DNA-like to highly distorted conformations that resembled those observed with Rad4 bound; the extent of these distortions increased with bound Rad4 and with temperature. Conversely, the non-specific TAT/TAT mismatch had a homogeneous, B-DNA-like conformation. Molecular dynamics simulations also revealed a wide distribution of conformations for CCC/CCC, complementing experimental findings. We propose that intrinsic deformability promotes Rad4 damage recognition, perhaps by stalling a diffusing protein and/or facilitating ‘conformational capture’ of pre-distorted damaged sites. Surprisingly, even mismatched DNA specifically bound to Rad4 remains highly dynamic, a feature that may reflect the versatility of Rad4/XPC to recognize many structurally dissimilar lesions.
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Affiliation(s)
- Sagnik Chakraborty
- Department of Physics, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Peter J Steinbach
- Center for Molecular Modeling, Center for Information Technology, National Institutes of Health, Bethesda, MD 20892, USA
| | - Debamita Paul
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Hong Mu
- Department of Biology, New York University, New York, NY 10003, USA
| | - Suse Broyde
- Department of Biology, New York University, New York, NY 10003, USA
| | - Jung-Hyun Min
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Anjum Ansari
- Department of Physics, University of Illinois at Chicago, Chicago, IL 60607, USA.,Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
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12
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Monakhova MV, Kubareva EA, Romanova EA, Semkina AS, Naberezhnov DS, Rao DN, Zatsepin TS, Oretskaya TS. Synthesis of β-Diketone DNA Derivatives for Affinity Modification of Proteins. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2019. [DOI: 10.1134/s1068162019020079] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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13
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Lahiri S, Li Y, Hingorani MM, Mukerji I. MutSγ-Induced DNA Conformational Changes Provide Insights into Its Role in Meiotic Recombination. Biophys J 2018; 115:2087-2101. [PMID: 30467025 DOI: 10.1016/j.bpj.2018.10.029] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 10/16/2018] [Accepted: 10/22/2018] [Indexed: 01/11/2023] Open
Abstract
In many organisms, MutSγ plays a role in meiotic recombination, facilitating crossover formation between homologous chromosomes. Failure to form crossovers leads to improper segregation of chromosomes and aneuploidy, which in humans result in infertility and birth defects. To improve current understanding of MutSγ function, this study investigates the binding affinities and structures of MutSγ in complex with DNA substrates that model homologous recombination intermediates. For these studies, we overexpressed and isolated from Escherichia coli the yeast MutSγ protein Saccharomyces cerevisiae (Sc) Msh4-Msh5. Sc Msh4-Msh5 binds Holliday junction (HJ)-like substrates, 3' overhangs, single-stranded (ss) forks, and the displacement loop with nanomolar affinity. The weakest binding affinities are detected for an intact duplex and open-junction construct. Similar to the human protein, Sc Msh4-Msh5 exhibits the highest affinity for the HJ with a Kd < 0.4 nM in solution. Energy-transfer experiments further demonstrate that DNA structure is modulated by the binding interaction with the largest changes associated with substrates containing an ss end. Upon binding, Sc Msh4-Msh5 displaces the ss away from the duplex in most of the ss-containing intermediates, potentially enabling the binding of RPA and other proteins. In the case of the junction-like intermediates, Msh4-Msh5 binding either stabilizes the existing stacked structure or induces formation of the stacked X conformation. Significantly, we find that upon binding, Msh4-Msh5 stacks an open-junction construct to the same extent as the standard junction. Stabilization of the junction in the stacked conformation is generally refractory to branch migration, which is consistent with a potential role for MutSγ to stabilize HJs and prevent branch migration until resolution by MutLγ. The different binding modalities observed suggest that Msh4-Msh5 not only binds to and stabilizes stacked junctions but also participates in meiotic recombination before junction formation through the stabilization of single-end invasion intermediates.
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Affiliation(s)
- Sudipta Lahiri
- Department of Molecular Biology and Biochemistry, Molecular Biophysics Program, Wesleyan University, Middletown, Connecticut
| | - Yan Li
- Department of Molecular Biology and Biochemistry, Molecular Biophysics Program, Wesleyan University, Middletown, Connecticut
| | - Manju M Hingorani
- Department of Molecular Biology and Biochemistry, Molecular Biophysics Program, Wesleyan University, Middletown, Connecticut
| | - Ishita Mukerji
- Department of Molecular Biology and Biochemistry, Molecular Biophysics Program, Wesleyan University, Middletown, Connecticut.
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14
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Melvin RL, Xiao J, Godwin RC, Berenhaut KS, Salsbury FR. Visualizing correlated motion with HDBSCAN clustering. Protein Sci 2018; 27:62-75. [PMID: 28799290 PMCID: PMC5734272 DOI: 10.1002/pro.3268] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 07/31/2017] [Accepted: 08/02/2017] [Indexed: 12/22/2022]
Abstract
Correlated motion analysis provides a method for understanding communication between and dynamic similarities of biopolymer residues and domains. The typical equal-time correlation matrices-frequently visualized with pseudo-colorings or heat maps-quickly convey large regions of highly correlated motion but hide more subtle similarities of motion. Here we propose a complementary method for visualizing correlations within proteins (or general biopolymers) that quickly conveys intuition about which residues have a similar dynamic behavior. For grouping residues, we use the recently developed non-parametric clustering algorithm HDBSCAN. Although the method we propose here can be used to group residues using correlation as a similarity matrix-the most straightforward and intuitive method-it can also be used to more generally determine groups of residues which have similar dynamic properties. We term these latter groups "Dynamic Domains", as they are based not on spatial closeness but rather closeness in the column space of a correlation matrix. We provide examples of this method across three human proteins of varying size and function-the Nf-Kappa-Beta essential modulator, the clotting promoter Thrombin and the mismatch repair protein (dimer) complex MutS-alpha. Although the examples presented here are from all-atom molecular dynamics simulations, this visualization technique can also be used on correlations matrices built from any ensembles of conformations from experiment or computation.
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Affiliation(s)
- Ryan L. Melvin
- Department of PhysicsWake Forest UniversityWinston SalemNorth Carolina
- Department of Mathematics and StatisticsWake Forest UniversityWinston‐SalemNorth Carolina27109
| | - Jiajie Xiao
- Department of PhysicsWake Forest UniversityWinston SalemNorth Carolina
- Department of Computer ScienceWake Forest UniversityWinston‐SalemNorth Carolina27109
| | - Ryan C. Godwin
- Department of PhysicsWake Forest UniversityWinston SalemNorth Carolina
| | - Kenneth S. Berenhaut
- Department of Mathematics and StatisticsWake Forest UniversityWinston‐SalemNorth Carolina27109
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15
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Růžička M, Kulhánek P, Radová L, Čechová A, Špačková N, Fajkusová L, Réblová K. DNA mutation motifs in the genes associated with inherited diseases. PLoS One 2017; 12:e0182377. [PMID: 28767725 PMCID: PMC5540541 DOI: 10.1371/journal.pone.0182377] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 07/17/2017] [Indexed: 11/18/2022] Open
Abstract
Mutations in human genes can be responsible for inherited genetic disorders and cancer. Mutations can arise due to environmental factors or spontaneously. It has been shown that certain DNA sequences are more prone to mutate. These sites are termed hotspots and exhibit a higher mutation frequency than expected by chance. In contrast, DNA sequences with lower mutation frequencies than expected by chance are termed coldspots. Mutation hotspots are usually derived from a mutation spectrum, which reflects particular population where an effect of a common ancestor plays a role. To detect coldspots/hotspots unaffected by population bias, we analysed the presence of germline mutations obtained from HGMD database in the 5-nucleotide segments repeatedly occurring in genes associated with common inherited disorders, in particular, the PAH, LDLR, CFTR, F8, and F9 genes. Statistically significant sequences (mutational motifs) rarely associated with mutations (coldspots) and frequently associated with mutations (hotspots) exhibited characteristic sequence patterns, e.g. coldspots contained purine tract while hotspots showed alternating purine-pyrimidine bases, often with the presence of CpG dinucleotide. Using molecular dynamics simulations and free energy calculations, we analysed the global bending properties of two selected coldspots and two hotspots with a G/T mismatch. We observed that the coldspots were inherently more flexible than the hotspots. We assume that this property might be critical for effective mismatch repair as DNA with a mutation recognized by MutSα protein is noticeably bent.
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Affiliation(s)
- Michal Růžička
- CEITEC—Central European Institute of Technology, Masaryk University, Kamenice 5, Brno, Czech Republic
- Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Kotlářská 2, Brno, Czech Republic
| | - Petr Kulhánek
- CEITEC—Central European Institute of Technology, Masaryk University, Kamenice 5, Brno, Czech Republic
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, Brno, Czech Republic
| | - Lenka Radová
- CEITEC—Central European Institute of Technology, Masaryk University, Kamenice 5, Brno, Czech Republic
| | - Andrea Čechová
- CEITEC—Central European Institute of Technology, Masaryk University, Kamenice 5, Brno, Czech Republic
| | - Naďa Špačková
- Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Kotlářská 2, Brno, Czech Republic
| | - Lenka Fajkusová
- Centre of Molecular Biology and Gene Therapy, University Hospital Brno and Masaryk University, Jihlavská 20, Brno, Czech Republic
| | - Kamila Réblová
- CEITEC—Central European Institute of Technology, Masaryk University, Kamenice 5, Brno, Czech Republic
- * E-mail:
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16
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Melvin RL, Thompson WG, Godwin RC, Gmeiner WH, Salsbury FR. MutS α's Multi-Domain Allosteric Response to Three DNA Damage Types Revealed by Machine Learning. FRONTIERS IN PHYSICS 2017; 5:10. [PMID: 31938712 PMCID: PMC6959842 DOI: 10.3389/fphy.2017.00010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
MutSα is a key component in the mismatch repair (MMR) pathway. This protein is responsible for initiating the signaling pathways for DNA repair or cell death. Herein we investigate this heterodimer's post-recognition, post-binding response to three types of DNA damage involving cytotoxic, anti-cancer agents-carboplatin, cisplatin, and FdU. Through a combination of supervised and unsupervised machine learning techniques along with more traditional structural and kinetic analysis applied to all-atom molecular dynamics (MD) calculations, we predict that MutSα has a distinct response to each of the three damage types. Via a binary classification tree (a supervised machine learning technique), we identify key hydrogen bond motifs unique to each type of damage and suggest residues for experimental mutation studies. Through a combination of a recently developed clustering (unsupervised learning) algorithm, RMSF calculations, PCA, and correlated motions we predict that each type of damage causes MutSα to explore a specific region of conformation space. Detailed analysis suggests a short range effect for carboplatin-primarily altering the structures and kinetics of residues within 10 angstroms of the damaged DNA-and distinct longer-range effects for cisplatin and FdU. In our simulations, we also observe that a key phenylalanine residue-known to stack with a mismatched or unmatched bases in MMR-stacks with the base complementary to the damaged base in 88.61% of MD frames containing carboplatinated DNA. Similarly, this Phe71 stacks with the base complementary to damage in 91.73% of frames with cisplatinated DNA. This residue, however, stacks with the damaged base itself in 62.18% of trajectory frames with FdU-substituted DNA and has no stacking interaction at all in 30.72% of these frames. Each drug investigated here induces a unique perturbation in the MutSα complex, indicating the possibility of a distinct signaling event and specific repair or death pathway (or set of pathways) for a given type of damage.
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Affiliation(s)
- Ryan L. Melvin
- Salsbury Group, Department of Physics, Wake Forest University, Winston-Salem, NC, USA
| | - William G. Thompson
- Salsbury Group, Department of Physics, Wake Forest University, Winston-Salem, NC, USA
| | - Ryan C. Godwin
- Salsbury Group, Department of Physics, Wake Forest University, Winston-Salem, NC, USA
| | - William H. Gmeiner
- Gmeiner Laboratory, Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Freddie R. Salsbury
- Salsbury Group, Department of Physics, Wake Forest University, Winston-Salem, NC, USA
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17
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Lakhani B, Thayer KM, Hingorani MM, Beveridge DL. Evolutionary Covariance Combined with Molecular Dynamics Predicts a Framework for Allostery in the MutS DNA Mismatch Repair Protein. J Phys Chem B 2017; 121:2049-2061. [PMID: 28135092 PMCID: PMC5346969 DOI: 10.1021/acs.jpcb.6b11976] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
![]()
Mismatch
repair (MMR) is an essential, evolutionarily conserved
pathway that maintains genome stability by correcting base-pairing
errors in DNA. Here we examine the sequence and structure of MutS
MMR protein to decipher the amino acid framework underlying its two
key activities—recognizing mismatches in DNA and using ATP
to initiate repair. Statistical coupling analysis (SCA) identified
a network (sector) of coevolved amino acids in the MutS protein family.
The potential functional significance of this SCA sector was assessed
by performing molecular dynamics (MD) simulations for alanine mutants
of the top 5% of 160 residues in the distribution, and control nonsector
residues. The effects on three independent metrics were monitored:
(i) MutS domain conformational dynamics, (ii) hydrogen bonding between
MutS and DNA/ATP, and (iii) relative ATP binding free energy. Each
measure revealed that sector residues contribute more substantively
to MutS structure–function than nonsector residues. Notably,
sector mutations disrupted MutS contacts with DNA and/or ATP from
a distance via contiguous pathways and correlated motions, supporting
the idea that SCA can identify amino acid networks underlying allosteric
communication. The combined SCA/MD approach yielded novel, experimentally
testable hypotheses for unknown roles of many residues distributed
across MutS, including some implicated in Lynch cancer syndrome.
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Affiliation(s)
- Bharat Lakhani
- Molecular Biology and Biochemistry Department, ‡Molecular Biophysics Program, §Chemistry Department, and ∥Computer Science Department, Wesleyan University , Middletown, Connecticut 06459, United States
| | - Kelly M Thayer
- Molecular Biology and Biochemistry Department, ‡Molecular Biophysics Program, §Chemistry Department, and ∥Computer Science Department, Wesleyan University , Middletown, Connecticut 06459, United States
| | - Manju M Hingorani
- Molecular Biology and Biochemistry Department, ‡Molecular Biophysics Program, §Chemistry Department, and ∥Computer Science Department, Wesleyan University , Middletown, Connecticut 06459, United States
| | - David L Beveridge
- Molecular Biology and Biochemistry Department, ‡Molecular Biophysics Program, §Chemistry Department, and ∥Computer Science Department, Wesleyan University , Middletown, Connecticut 06459, United States
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18
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Wei G, Xi W, Nussinov R, Ma B. Protein Ensembles: How Does Nature Harness Thermodynamic Fluctuations for Life? The Diverse Functional Roles of Conformational Ensembles in the Cell. Chem Rev 2016; 116:6516-51. [PMID: 26807783 PMCID: PMC6407618 DOI: 10.1021/acs.chemrev.5b00562] [Citation(s) in RCA: 253] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
All soluble proteins populate conformational ensembles that together constitute the native state. Their fluctuations in water are intrinsic thermodynamic phenomena, and the distributions of the states on the energy landscape are determined by statistical thermodynamics; however, they are optimized to perform their biological functions. In this review we briefly describe advances in free energy landscape studies of protein conformational ensembles. Experimental (nuclear magnetic resonance, small-angle X-ray scattering, single-molecule spectroscopy, and cryo-electron microscopy) and computational (replica-exchange molecular dynamics, metadynamics, and Markov state models) approaches have made great progress in recent years. These address the challenging characterization of the highly flexible and heterogeneous protein ensembles. We focus on structural aspects of protein conformational distributions, from collective motions of single- and multi-domain proteins, intrinsically disordered proteins, to multiprotein complexes. Importantly, we highlight recent studies that illustrate functional adjustment of protein conformational ensembles in the crowded cellular environment. We center on the role of the ensemble in recognition of small- and macro-molecules (protein and RNA/DNA) and emphasize emerging concepts of protein dynamics in enzyme catalysis. Overall, protein ensembles link fundamental physicochemical principles and protein behavior and the cellular network and its regulation.
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Affiliation(s)
- Guanghong Wei
- State Key Laboratory of Surface Physics, Key Laboratory for Computational Physical Sciences (MOE), and Department of Physics, Fudan University, Shanghai, P. R. China
| | - Wenhui Xi
- State Key Laboratory of Surface Physics, Key Laboratory for Computational Physical Sciences (MOE), and Department of Physics, Fudan University, Shanghai, P. R. China
| | - Ruth Nussinov
- Basic Science Program, Leidos Biomedical Research, Inc. Cancer and Inflammation Program, National Cancer Institute, Frederick, Maryland 21702, USA
- Sackler Inst. of Molecular Medicine Department of Human Genetics and Molecular Medicine Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Buyong Ma
- Basic Science Program, Leidos Biomedical Research, Inc. Cancer and Inflammation Program, National Cancer Institute, Frederick, Maryland 21702, USA
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19
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Hermans N, Laffeber C, Cristovão M, Artola-Borán M, Mardenborough Y, Ikpa P, Jaddoe A, Winterwerp HHK, Wyman C, Jiricny J, Kanaar R, Friedhoff P, Lebbink JHG. Dual daughter strand incision is processive and increases the efficiency of DNA mismatch repair. Nucleic Acids Res 2016; 44:6770-86. [PMID: 27174933 PMCID: PMC5001592 DOI: 10.1093/nar/gkw411] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 05/03/2016] [Indexed: 12/27/2022] Open
Abstract
DNA mismatch repair (MMR) is an evolutionarily-conserved process responsible for the repair of replication errors. In Escherichia coli, MMR is initiated by MutS and MutL, which activate MutH to incise transiently-hemimethylated GATC sites. MMR efficiency depends on the distribution of these GATC sites. To understand which molecular events determine repair efficiency, we quantitatively studied the effect of strand incision on unwinding and excision activity. The distance between mismatch and GATC site did not influence the strand incision rate, and an increase in the number of sites enhanced incision only to a minor extent. Two GATC sites were incised by the same activated MMR complex in a processive manner, with MutS, the closed form of MutL and MutH displaying different roles. Unwinding and strand excision were more efficient on a substrate with two nicks flanking the mismatch, as compared to substrates containing a single nick or two nicks on the same side of the mismatch. Introduction of multiple nicks by the human MutLα endonuclease also contributed to increased repair efficiency. Our data support a general model of prokaryotic and eukaryotic MMR in which, despite mechanistic differences, mismatch-activated complexes facilitate efficient repair by creating multiple daughter strand nicks.
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Affiliation(s)
- Nicolaas Hermans
- Department of Molecular Genetics, Cancer Genomics Netherlands, Erasmus Medical Center Rotterdam, 3015 AA Rotterdam,The Netherlands
| | - Charlie Laffeber
- Department of Molecular Genetics, Cancer Genomics Netherlands, Erasmus Medical Center Rotterdam, 3015 AA Rotterdam,The Netherlands
| | - Michele Cristovão
- Department of Molecular Genetics, Cancer Genomics Netherlands, Erasmus Medical Center Rotterdam, 3015 AA Rotterdam,The Netherlands
| | - Mariela Artola-Borán
- Institute of Molecular Cancer Research of the University of Zurich and ETH Zurich, Winterthurerstrasse 190, CH 8057 Zurich, Switzerland
| | - Yannicka Mardenborough
- Department of Molecular Genetics, Cancer Genomics Netherlands, Erasmus Medical Center Rotterdam, 3015 AA Rotterdam,The Netherlands
| | - Pauline Ikpa
- Department of Molecular Genetics, Cancer Genomics Netherlands, Erasmus Medical Center Rotterdam, 3015 AA Rotterdam,The Netherlands
| | - Aruna Jaddoe
- Department of Molecular Genetics, Cancer Genomics Netherlands, Erasmus Medical Center Rotterdam, 3015 AA Rotterdam,The Netherlands
| | - Herrie H K Winterwerp
- Division of Biochemistry and Center for Biomedical Genetics, Netherlands Cancer Institute, 1006 BE Amsterdam, The Netherlands
| | - Claire Wyman
- Department of Molecular Genetics, Cancer Genomics Netherlands, Erasmus Medical Center Rotterdam, 3015 AA Rotterdam,The Netherlands Department of Radiation Oncology, Erasmus Medical Center Rotterdam, 3015 CE Rotterdam, The Netherlands
| | - Josef Jiricny
- Institute of Molecular Cancer Research of the University of Zurich and ETH Zurich, Winterthurerstrasse 190, CH 8057 Zurich, Switzerland
| | - Roland Kanaar
- Department of Molecular Genetics, Cancer Genomics Netherlands, Erasmus Medical Center Rotterdam, 3015 AA Rotterdam,The Netherlands Department of Radiation Oncology, Erasmus Medical Center Rotterdam, 3015 CE Rotterdam, The Netherlands
| | - Peter Friedhoff
- Institute for Biochemistry, Justus-Liebig-University, D-35392 Giessen, Germany
| | - Joyce H G Lebbink
- Department of Molecular Genetics, Cancer Genomics Netherlands, Erasmus Medical Center Rotterdam, 3015 AA Rotterdam,The Netherlands Department of Radiation Oncology, Erasmus Medical Center Rotterdam, 3015 CE Rotterdam, The Netherlands
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20
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Hingorani MM. Mismatch binding, ADP-ATP exchange and intramolecular signaling during mismatch repair. DNA Repair (Amst) 2016; 38:24-31. [PMID: 26704427 PMCID: PMC4740199 DOI: 10.1016/j.dnarep.2015.11.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Revised: 09/08/2015] [Accepted: 11/30/2015] [Indexed: 12/16/2022]
Abstract
The focus of this article is on the DNA binding and ATPase activities of the mismatch repair (MMR) protein, MutS-our current understanding of how this protein uses ATP to fuel its actions on DNA and initiate repair via interactions with MutL, the next protein in the pathway. Structure-function and kinetic studies have yielded detailed views of the MutS mechanism of action in MMR. How MutS and MutL work together after mismatch recognition to enable strand-specific nicking, which leads to strand excision and synthesis, is less clear and remains an active area of investigation.
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21
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Manhart CM, Alani E. Roles for mismatch repair family proteins in promoting meiotic crossing over. DNA Repair (Amst) 2016; 38:84-93. [PMID: 26686657 PMCID: PMC4740264 DOI: 10.1016/j.dnarep.2015.11.024] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 08/14/2015] [Accepted: 11/30/2015] [Indexed: 12/13/2022]
Abstract
The mismatch repair (MMR) family complexes Msh4-Msh5 and Mlh1-Mlh3 act with Exo1 and Sgs1-Top3-Rmi1 in a meiotic double strand break repair pathway that results in the asymmetric cleavage of double Holliday junctions (dHJ) to form crossovers. This review discusses how meiotic roles for Msh4-Msh5 and Mlh1-Mlh3 do not fit paradigms established for post-replicative MMR. We also outline models used to explain how these factors promote the formation of meiotic crossovers required for the accurate segregation of chromosome homologs during the Meiosis I division.
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Affiliation(s)
- Carol M Manhart
- Department of Molecular Biology and Genetics, Cornell University, 457 Biotechnology Building, Ithaca, NY 14853-2703, USA
| | - Eric Alani
- Department of Molecular Biology and Genetics, Cornell University, 457 Biotechnology Building, Ithaca, NY 14853-2703, USA.
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22
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Gauer J, LeBlanc S, Hao P, Qiu R, Case B, Sakato M, Hingorani M, Erie D, Weninger K. Single-Molecule FRET to Measure Conformational Dynamics of DNA Mismatch Repair Proteins. Methods Enzymol 2016; 581:285-315. [PMID: 27793283 PMCID: PMC5423442 DOI: 10.1016/bs.mie.2016.08.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Single-molecule FRET measurements have a unique sensitivity to protein conformational dynamics. The FRET signals can either be interpreted quantitatively to provide estimates of absolute distance in a molecule configuration or can be qualitatively interpreted as distinct states, from which quantitative kinetic schemes for conformational transitions can be deduced. Here we describe methods utilizing single-molecule FRET to reveal the conformational dynamics of the proteins responsible for DNA mismatch repair. Experimental details about the proteins, DNA substrates, fluorescent labeling, and data analysis are included. The complementarity of single molecule and ensemble kinetic methods is discussed as well.
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Affiliation(s)
- J.W. Gauer
- University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - S. LeBlanc
- University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - P. Hao
- North Carolina State University, Raleigh, NC, United States
| | - R. Qiu
- North Carolina State University, Raleigh, NC, United States
| | - B.C. Case
- Wesleyan University, Middletown, CT, United States
| | - M. Sakato
- Wesleyan University, Middletown, CT, United States
| | | | - D.A. Erie
- University of North Carolina at Chapel Hill, Chapel Hill, NC, United States,Corresponding authors: ;
| | - K.R. Weninger
- North Carolina State University, Raleigh, NC, United States,Corresponding authors: ;
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23
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Single-molecule motions and interactions in live cells reveal target search dynamics in mismatch repair. Proc Natl Acad Sci U S A 2015; 112:E6898-906. [PMID: 26575623 DOI: 10.1073/pnas.1507386112] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
MutS is responsible for initiating the correction of DNA replication errors. To understand how MutS searches for and identifies rare base-pair mismatches, we characterized the dynamic movement of MutS and the replisome in real time using superresolution microscopy and single-molecule tracking in living cells. We report that MutS dynamics are heterogeneous in cells, with one MutS population exploring the nucleoid rapidly, while another MutS population moves to and transiently dwells at the replisome region, even in the absence of appreciable mismatch formation. Analysis of MutS motion shows that the speed of MutS is correlated with its separation distance from the replisome and that MutS motion slows when it enters the replisome region. We also show that mismatch detection increases MutS speed, supporting the model for MutS sliding clamp formation after mismatch recognition. Using variants of MutS and the replication processivity clamp to impair mismatch repair, we find that MutS dynamically moves to and from the replisome before mismatch binding to scan for errors. Furthermore, a block to DNA synthesis shows that MutS is only capable of binding mismatches near the replisome. It is well-established that MutS engages in an ATPase cycle, which is necessary for signaling downstream events. We show that a variant of MutS with a nucleotide binding defect is no longer capable of dynamic movement to and from the replisome, showing that proper nucleotide binding is critical for MutS to localize to the replisome in vivo. Our results provide mechanistic insight into the trafficking and movement of MutS in live cells as it searches for mismatches.
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24
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Abstract
DNA mismatch repair (MMR) identifies and corrects errors made during replication. In all organisms except those expressing MutH, interactions between a DNA mismatch, MutS, MutL, and the replication processivity factor (β-clamp or PCNA) activate the latent MutL endonuclease to nick the error-containing daughter strand. This nick provides an entry point for downstream repair proteins. Despite the well-established significance of strand-specific nicking in MMR, the mechanism(s) by which MutS and MutL assemble on mismatch DNA to allow the subsequent activation of MutL's endonuclease activity by β-clamp/PCNA remains elusive. In both prokaryotes and eukaryotes, MutS homologs undergo conformational changes to a mobile clamp state that can move away from the mismatch. However, the function of this MutS mobile clamp is unknown. Furthermore, whether the interaction with MutL leads to a mobile MutS-MutL complex or a mismatch-localized complex is hotly debated. We used single molecule FRET to determine that Thermus aquaticus MutL traps MutS at a DNA mismatch after recognition but before its conversion to a sliding clamp. Rather than a clamp, a conformationally dynamic protein assembly typically containing more MutL than MutS is formed at the mismatch. This complex provides a local marker where interaction with β-clamp/PCNA could distinguish parent/daughter strand identity. Our finding that MutL fundamentally changes MutS actions following mismatch detection reframes current thinking on MMR signaling processes critical for genomic stability.
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25
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The role of Asn-212 in the catalytic mechanism of human endonuclease APE1: stopped-flow kinetic study of incision activity on a natural AP site and a tetrahydrofuran analogue. DNA Repair (Amst) 2015; 21:43-54. [PMID: 25038572 DOI: 10.1016/j.dnarep.2014.06.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 06/18/2014] [Accepted: 06/19/2014] [Indexed: 11/21/2022]
Abstract
Mammalian AP endonuclease 1 is a pivotal enzyme of the base excision repair pathway acting on apurinic/apyrimidinic sites. Previous structural and biochemical studies showed that the conserved Asn-212 residue is important for the enzymatic activity of APE1. Here, we report a comprehensive pre-steady-state kinetic analysis of two APE1 mutants, each containing amino acid substitutions at position 212, to ascertain the role of Asn-212 in individual steps of the APE1 catalytic mechanism. We applied the stopped-flow technique for detection of conformational transitions in the mutant proteins and DNA substrates during the catalytic cycle, using fluorophores that are sensitive to the micro-environment. Our data indicate that Asn-212 substitution by Asp reduces the rate of the incision step by ∼550-fold, while Ala substitution results in ∼70,000-fold decrease. Analysis of the binding steps revealed that both mutants continued to rapidly and efficiently bind to abasic DNA containing the natural AP site or its tetrahydrofuran analogue (F). Moreover, transient kinetic analysis showed that N212A APE1 possessed a higher binding rate and a higher affinity for specific substrates compared to N212D APE1. Molecular dynamics (MD) simulation revealed a significant dislocation of the key catalytic residues of both mutant proteins relative to wild-type APE1. The analysis of the model structure of N212D APE1 provides evidence for alternate hydrogen bonding between Asn-212 and Asp-210 residues, whereas N212A possesses an extended active site pocket due to Asn removal. Taken together, these biochemical and MD simulation results indicate that Asn-212 is essential for abasic DNA incision, but is not crucial for effective recognition/binding.
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26
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Kumar C, Eichmiller R, Wang B, Williams GM, Bianco PR, Surtees JA. ATP binding and hydrolysis by Saccharomyces cerevisiae Msh2-Msh3 are differentially modulated by mismatch and double-strand break repair DNA substrates. DNA Repair (Amst) 2014; 18:18-30. [PMID: 24746922 DOI: 10.1016/j.dnarep.2014.03.032] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 03/24/2014] [Accepted: 03/31/2014] [Indexed: 01/08/2023]
Abstract
In Saccharomyces cerevisiae, Msh2-Msh3-mediated mismatch repair (MMR) recognizes and targets insertion/deletion loops for repair. Msh2-Msh3 is also required for 3' non-homologous tail removal (3'NHTR) in double-strand break repair. In both pathways, Msh2-Msh3 binds double-strand/single-strand junctions and initiates repair in an ATP-dependent manner. However, we recently demonstrated that the two pathways have distinct requirements with respect to Msh2-Msh3 activities. We identified a set of aromatic residues in the nucleotide binding pocket (FLY motif) of Msh3 that, when mutated, disrupted MMR, but left 3'NHTR largely intact. One of these mutations, msh3Y942A, was predicted to disrupt the nucleotide sandwich and allow altered positioning of ATP within the pocket. To develop a mechanistic understanding of the differential requirements for ATP binding and/or hydrolysis in the two pathways, we characterized Msh2-Msh3 and Msh2-msh3Y942A ATP binding and hydrolysis activities in the presence of MMR and 3'NHTR DNA substrates. We observed distinct, substrate-dependent ATP hydrolysis and nucleotide turnover by Msh2-Msh3, indicating that the MMR and 3'NHTR DNA substrates differentially modify the ATP binding/hydrolysis activities of Msh2-Msh3. Msh2-msh3Y942A retained the ability to bind DNA and ATP but exhibited altered ATP hydrolysis and nucleotide turnover. We propose that both ATP and structure-specific repair substrates cooperate to direct Msh2-Msh3-mediated repair and suggest an explanation for the msh3Y942A separation-of-function phenotype.
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Affiliation(s)
- Charanya Kumar
- Department of Biochemistry, Immunology, University at Buffalo (SUNY), Buffalo, NY 14214, USA
| | - Robin Eichmiller
- Department of Biochemistry, Immunology, University at Buffalo (SUNY), Buffalo, NY 14214, USA
| | - Bangchen Wang
- Department of Biochemistry, Immunology, University at Buffalo (SUNY), Buffalo, NY 14214, USA
| | - Gregory M Williams
- Department of Biochemistry, Immunology, University at Buffalo (SUNY), Buffalo, NY 14214, USA
| | - Piero R Bianco
- Department of Microbiology and Immunology, University at Buffalo (SUNY), Buffalo, NY 14214, USA
| | - Jennifer A Surtees
- Department of Biochemistry, Immunology, University at Buffalo (SUNY), Buffalo, NY 14214, USA.
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