MutS mediates heteroduplex loop formation by a translocation mechanism

Allen, Dwayne J.; Makhov, Alexander M.; Grilley, Michelle; Taylor, John Hermon; Thresher, Randy J.; Modrich, Paul; Griffith, Jack D.

doi:10.1093/emboj/16.14.4467

Cited by 302 publications

(297 citation statements)

References 32 publications

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“…5A, the maximum level of binding of MutS to the heteroduplex GG/CT is much higher as compared with that of the perfectly paired duplex, as expected for a mismatch binding protein. As deduced at saturation binding obtained at a higher protein concentration (RU max ϭ 650, data not shown), MutS as a dimer was found to bind to the heteroduplex in a 1:1 manner, in agreement with previous studies (40,49). Adding a cisplatin 1,2-intrastrand adduct to the GG/CC homoduplex results in an increase of the plateau level.…”

Section: Muts Recognizes An Extensive Set Of Cisplatin 12-intrastransupporting

confidence: 90%

Binding Discrimination of MutS to a Set of Lesions and Compound Lesions (Base Damage and Mismatch) Reveals Its Potential Role as a Cisplatin-damaged DNA Sensing Protein

Fourrier

Brooks²,

Malinge³

2003

Journal of Biological Chemistry

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The DNA mismatch repair (MMR) system plays a critical role in sensitizing both prokaryotic and eukaryotic cells to the clinically potent anticancer drug cisplatin. It is thought to mediate cytotoxicity through recognition of cisplatin DNA lesions. This drug generates a range of lesions that may also give rise to compound lesions resulting from the misincorporation of a base during translesion synthesis. Using gel mobility shift competition assays and surface plasmon resonance, we have analyzed the interaction of Escherichia coli MutS protein with site-specifically modified DNA oligonucleotides containing each of the four cisplatin cross-links or a set of compound lesions. The major 1,2-d(GpG) cisplatin intrastrand cross-link was recognized with only a 1.5-fold specificity, whereas a 47-fold specificity was found with a natural G/T containing DNA substrate. The rate of association, k on, for binding to the 1,2-d(GpG) adduct was 3.1 ؋ 10 4 M ؊1 s ؊1 and the specificity of binding was essentially dependent on k off . DNA duplexes containing a single 1,2-d(ApG), 1,3-d(GpCpG) adduct, and an interstrand cross-link of cisplatin were not preferentially recognized. Among 12 DNA substrates, each containing a different cisplatin compound lesion derived from replicative misincorporation of one base opposite either of the 1,2-intrastrand adducts, 10 were specifically recognized including those that are more likely formed in vivo based on cisplatin mutation spectra. Moreover, among these lesions, two compound lesions formed when an adenine was misincorporated opposite a 1,2-d(GpG) adduct were not substrates for the MutYdependent mismatch repair pathway. The ability of MutS to sense differentially various platinated DNA substrates suggests that cisplatin compound lesions formed during misincorporation of a base opposite either adducted base of both 1,2-intrastrand cross-links are more plausible critical lesions for MMR-mediated cisplatin cytotoxicity.cis-Diamminedichloroplatinum(II) (cisplatin) 1 is among the most widely used anticancer chemotherapeutic agents in the treatment of many human tumors, particularly testicular and ovarian tumors (1). In the reaction between DNA and cisplatin, different types of bifunctional adducts are formed that are thought to be the key toxic lesions (2-4). Although these adducts are responsible for a variety of cellular responses including replication and/or transcription inhibition, there is not yet a clear understanding of the molecular mechanisms linking the formation of adducts and cisplatin-induced apoptosis (5, 6). Cisplatin reacts preferentially with the N-7 atoms of purine residues in DNA. The major adducts (90%) are 1,2-intrastrand cross-links at d(GpG) and d(ApG) sites and the minor adducts correspond to 1,3-intrastrand cross-links at d(GpNpG) (N being a nucleotide residue) and interstrand cross-links formed at d(GpC/GpC) sites (7-10). Once formed, cisplatin lesions such as the major 1,2-intrastrand cross-links can undergo replication bypass in cells treated with cisplatin (11,12). Be...

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Section: Muts Recognizes An Extensive Set Of Cisplatin 12-intrastransupporting

confidence: 90%

Binding Discrimination of MutS to a Set of Lesions and Compound Lesions (Base Damage and Mismatch) Reveals Its Potential Role as a Cisplatin-damaged DNA Sensing Protein

Fourrier

Brooks²,

Malinge³

2003

Journal of Biological Chemistry

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“…The heteroduplexes used in these experiments contain an NheI site 5 bp from the mismatch, which is rendered resistant to cleavage by MutS binding (12). As shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…One invokes movement of MutS or the MutL-MutS complex along the helix between the mismatch and the strand signal (11)(12)(13), a second posits mismatch recognition by MutS as a trigger for polymerization of a second protein along the helix between the two DNA sites (11), and the third attributes interaction of the two sites to a DNA-looping mechanism (14,15). Several laboratories have demonstrated that, when challenged with ATP, MutS homologs leave a mismatch by movement along the helix contour, and evidence for movement of the MutL-MutS homolog complex along DNA also is available (reviewed in refs.…”

mentioning

confidence: 99%

Protein roadblocks and helix discontinuities are barriers to the initiation of mismatch repair

Pluciennik¹,

Modrich

2007

Proc. Natl. Acad. Sci. U.S.A.

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The hemimethylated d(GATC) sequence that directs Escherichia coli mismatch repair can reside on either side of a mismatch at a separation distance of 1,000 bp or more. Initiation of repair involves the mismatch-, MutS-, and MutL-dependent activation of MutH endonuclease, which incises the unmethylated strand at the d(GATC) sequence, with the ensuing strand break serving as the loading site for the appropriate 3 -to-5 or 5 -to-3 excision system. However, the mechanism responsible for the coordinated recognition of the mismatch and a hemimodified d(GATC) site is uncertain. We show that a protein roadblock (EcoRIE111Q, a hydrolytically defective form of EcoRI endonuclease) placed on the helix between the two DNA sites inhibits MutH activation by 70 -80% and that events that escape inhibition are attributable, at least in part, to diffusion of EcoRIE111Q away from its recognition site. We also demonstrate that a double-strand break located within the shorter path linking the mismatch and a d(GATC) site in a circular heteroduplex abolishes MutH activation, whereas a double-strand break within the longer path is without effect. These findings support the idea that initiation of mismatch repair involves signaling along the helix contour.DNA repair ͉ genetic stability ͉ signaling M ismatch repair is a conserved process that corrects biosynthetic errors and ensures the fidelity of homologous genetic recombination. Eleven activities have been implicated in Escherichia coli methyl-directed mismatch repair that has been reconstituted in a purified system. The reaction depends on MutS, MutL, MutH, DNA helicase II (MutU/UvrD), singlestranded DNA-binding protein, exonuclease I, exonuclease VII, exonuclease X, RecJ exonuclease, DNA polymerase III holoenzyme, and DNA ligase (1-4). The strand specificity necessary for replication error correction by this system is based on the transient absence of d(GATC) methylation in newly synthesized DNA (5).Repair is initiated via mismatch recognition by MutS (6), which recruits MutL to the heteroduplex in a mismatch-and ATP-dependent fashion (7,8). Assembly of the MutL-MutSheteroduplex complex is sufficient to activate MutH endonuclease, which incises the unmethylated strand of a hemimethylated d(GATC)-strand signal (9) that may reside either 3Ј or 5Ј to the mismatch at distances of as much as 1 kb or more (2). MutS and MutL also activate DNA helicase II, which is loaded at the MutH strand break in an orientation-dependent manner, so that helix unwinding proceeds toward the mismatch (10). That portion of the incised strand displaced in this manner is degraded by a single-stranded exonuclease, resulting in mismatch removal. When the MutH nick is 3Ј to the mismatch, the single-stranded hydrolytic requirement can be met by exonuclease I, exonuclease VII, or exonuclease X, and, when the nick is 5Ј to the mispair, either exonuclease VII or RecJ will suffice in this regard (2-4). The mechanism responsible for action at a distance during mismatch repair is poorly understood, but the bidirectional ...

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“…Several research groups have reported an apparent reduction in the affinity of MutS for mismatched DNA following ATP binding, which manifests as MutS sliding off short linear mismatched DNA substrates with unblocked ends during gel mobility-shift analysis (1,13,(23)(24)(25)28,48); presumably, such movement of MutS on DNA serves an important function during mismatch repair. Since we have now identified some nucleotide-bound forms of MutS in the pathway, we tested their interaction with +T-containing duplex DNA substrate.…”

Section: What Is Their Function?mentioning

confidence: 99%

Asymmetric ATP Binding and Hydrolysis Activity of the Thermus aquaticus MutS Dimer Is Key to Modulation of Its Interactions with Mismatched DNA

2004

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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.Mismatch repair maintains genomic integrity by correcting mispaired bases and insertions or deletions that occur in DNA due to errors in DNA replication or recombination. The process initiates with a mismatch recognition phase, in which MutS protein binds to the distortion in the DNA duplex, followed by excision of the offending DNA strand, catalyzed by helicase and exonuclease enzymes, and finally DNA resynthesis and ligation of the new strand, apparently by the normal DNA replication machinery (1). In Escherichia coli, after MutS (a homodimer) binds the mismatch, it interacts with MutL (also a homodimer), resulting in stimulation of MutH endonuclease activity and nicking of the mismatch-containing DNA strand to initiate strand excision (2-4). Since these core components of the DNA mismatch repair system were identified in E. coli, homologues of MutS and MutL have been discovered and analyzed in numerous other organisms, including humans. Eukaryotic MutS proteins function as heterodimers, such as Msh2-Msh6, 1 which recognizes base pair mismatches and small insertion or deletion loops, and Msh2-Msh3, which appears to be specific for insertion or † This work was supported by a grant from the N. .

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MutS mediates heteroduplex loop formation by a translocation mechanism

Cited by 302 publications

References 32 publications

Binding Discrimination of MutS to a Set of Lesions and Compound Lesions (Base Damage and Mismatch) Reveals Its Potential Role as a Cisplatin-damaged DNA Sensing Protein

Binding Discrimination of MutS to a Set of Lesions and Compound Lesions (Base Damage and Mismatch) Reveals Its Potential Role as a Cisplatin-damaged DNA Sensing Protein

Protein roadblocks and helix discontinuities are barriers to the initiation of mismatch repair

Asymmetric ATP Binding and Hydrolysis Activity of the Thermus aquaticus MutS Dimer Is Key to Modulation of Its Interactions with Mismatched DNA

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