GO:0030983 mismatched DNA binding: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0030983 mismatched DNA binding is a molecular function defined as binding to a double-stranded DNA region containing one or more mismatches.
• The human MSH2 protein was the first mismatch-binding factor shown to recognize mismatched microsatellite DNA sequences.
• Yeast Msh2-Msh6 and Mlh1-Pms1 heterodimers display distinct DNA binding properties that underpin mismatch recognition and repair.
• Mismatch binding ligands and metal ions can be used as chemical probes to detect and enrich mismatched DNA [1,2,3,7].
• DNA charge transport provides a label-free sensing strategy for detecting mismatched DNA binding events.
• Mismatched DNA binding is central to DNA mismatch repair, genome stability, and cancer predisposition research [5,6].
Description
GO:0030983 mismatched DNA binding is a molecular function that describes the binding of a protein or chemical entity to a double-stranded DNA region containing one or more mismatches. This function is fundamental to DNA mismatch repair, where specialized proteins must locate and engage mispaired bases within the genome to maintain replication fidelity [5,6]. The human MSH2 protein was shown to bind mismatched microsatellite DNA sequences, establishing a direct biochemical link between mismatch recognition and genome stability. Beyond protein factors, small molecules and metal ions can also bind mismatched DNA, making this function relevant to chemical biology and biosensing [1,2,3,4]. The yeast Msh2-Msh6 and Mlh1-Pms1 heterodimers exhibit distinct DNA binding properties that help define how mismatch recognition is coupled to downstream repair events. Because mismatched DNA binding is a prerequisite for mismatch repair, defects in this function are associated with cancer predisposition and genome instability [5,6]. Researchers study this term using biochemical binding assays, affinity chromatography, and electrochemical sensing approaches [7,8].
mismatched DNA binding At A Glance
| GO ID | GO:0030983 |
|---|---|
| GO term | mismatched DNA binding |
| Ontology | molecular_function |
| Synonym | mispair binding; mispaired DNA binding |
| Definition | Binding to a double-stranded DNA region containing one or more mismatches. |
| Major function | Recognition and engagement of mispaired bases within double-stranded DNA. |
| Representative proteins | MSH2, MSH6, MLH1, PMS1 and their heterodimers [5,6]. |
| Chemical probes | Mismatch binding ligands, metal ions, and intercalating metal complexes [1,2,3,4,7]. |
| Detection methods | Affinity chromatography, calorimetry, and DNA charge transport sensing [3,7,8]. |
What Is GO:0030983?
In simple terms, mismatched DNA binding means a molecule attaches to a double-stranded DNA region where the two strands do not perfectly match. The QuickGO definition states that this molecular function is the binding to a double-stranded DNA region containing one or more mismatches. It is a molecular_function term with synonyms including mispair binding and mispaired DNA binding. This function is distinct from sequence-specific binding to perfectly matched DNA because it depends on the presence of a mispaired or unmatched base within the duplex.
Why Is mismatched DNA binding Important in Cell Biology?
Mismatched DNA binding is important because it is the initial recognition step in DNA mismatch repair, a pathway that protects genome integrity by correcting replication errors [5,6]. The human MSH2 protein binds mismatched microsatellite DNA sequences, and this binding activity is directly relevant to understanding how mismatch repair defects contribute to cancer. Yeast Msh2-Msh6 and Mlh1-Pms1 heterodimers provide a tractable model for dissecting the DNA binding properties that initiate repair. In addition, mismatched DNA binding is exploited in biotechnology, where mismatch binding ligands and metal ions are used to detect or enrich mismatched DNA [1,2,3,7]. DNA charge transport offers a label-free route to sense mismatch binding events, linking fundamental biochemistry to biosensor development. Thus, GO:0030983 connects basic DNA repair biology, disease mechanisms, and molecular detection technologies [5,6,7,8].
• Mismatched DNA binding initiates DNA mismatch repair and helps maintain genome stability [5,6].
• The human MSH2 protein directly binds mismatched microsatellite DNA sequences.
• Yeast Msh2-Msh6 and Mlh1-Pms1 heterodimers show distinct mismatch DNA binding properties.
• Defects in mismatch recognition are linked to cancer predisposition and microsatellite instability [5,6].
• Mismatch binding ligands enable affinity enrichment of mismatched DNA for analysis.
• Metal ions such as Hg(2+) can specifically bind mismatched base pairs involving 5-hydroxyuracil.
• Isothermal titration calorimetry can detect direct metal ion binding to mismatched base pairs.
• Epirubicin hydrochloride preferentially binds single nucleotide mismatched DNA.
• Ruthenium complexes can discriminate between matched and mismatched DNA.
• DNA charge transport provides a sensitive readout of mismatched DNA binding.
What Happens During mismatched DNA binding?
Recognition of the mismatch
In simple terms: The binding molecule first finds the spot where the DNA strands do not match.
The human MSH2 protein was shown to bind mismatched microsatellite DNA sequences, demonstrating direct recognition of mispaired bases within a duplex. Yeast Msh2-Msh6 heterodimers also exhibit DNA binding properties consistent with mismatch recognition. This step is the molecular basis of GO:0030983 and determines whether downstream repair or detection can proceed [5,6].
Stable engagement of the mispaired duplex
In simple terms: After finding the mismatch, the binding molecule holds onto the DNA.
Mismatch binding ligands can be immobilized on Sepharose to capture mismatched DNA, showing that stable engagement of mispaired duplexes is achievable in affinity chromatography formats. Metal ions such as Hg(2+) can specifically bind mismatched base pairs involving 5-hydroxyuracil in duplex DNA, further illustrating stable chemical engagement of mismatches. Isothermal titration calorimetry has been used to detect direct binding of metal ions to mismatched base pairs, providing thermodynamic evidence for stable engagement.
Discrimination between matched and mismatched DNA
In simple terms: The binding molecule must tell the difference between perfect and imperfect DNA.
Ru(bpy)2(eilatin)2+ was shown to bind matched and mismatched DNA with different behavior, demonstrating that discrimination is possible with small molecules. Epirubicin hydrochloride preferentially binds single nucleotide mismatched DNA and can subsequently be sequestered by a mixed micelle, indicating selectivity for mismatched sites. Yeast Msh2-Msh6 and Mlh1-Pms1 heterodimers display distinct DNA binding properties that contribute to discrimination during mismatch recognition.
Signal generation and detection
In simple terms: Binding to a mismatch can be converted into a measurable signal.
DNA charge transport can sense DNA binding events, providing a label-free strategy to detect mismatched DNA binding. Mismatch binding ligand-Sepharose affinity chromatography allows enrichment and analysis of mismatched DNA. Isothermal titration calorimetry quantifies direct binding of metal ions to mismatched base pairs, offering a thermodynamically resolved detection method.
Key Genes Involved in GO:0030983 mismatched DNA binding
The following genes and proteins are directly implicated in mismatched DNA binding or in the biochemical detection of mismatched DNA, based on the verified literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| MSH2 | Binds mismatched microsatellite DNA sequences | Core mismatch recognition factor; cancer and genome stability studies |
| MSH6 | Partners with Msh2 in yeast Msh2-Msh6 heterodimer | Mismatch DNA binding properties of the heterodimer |
| MLH1 | Partners with Pms1 in yeast Mlh1-Pms1 heterodimer | DNA binding properties of the heterodimer |
| PMS1 | Partners with Mlh1 in yeast Mlh1-Pms1 heterodimer | DNA binding properties of the heterodimer |
| MSH2 (human) | Binds mismatched microsatellite DNA | Direct biochemical evidence for mismatch binding |
| Msh2 (yeast) | Mismatch recognition subunit | Model system for mismatch binding assays |
| Msh6 (yeast) | Mismatch recognition subunit | Model system for mismatch binding assays |
| Mlh1 (yeast) | Heterodimer partner | DNA binding characterization |
| Pms1 (yeast) | Heterodimer partner | DNA binding characterization |
| MSH2-related mismatch binding factors | Recognize mispaired bases | Comparative binding studies |
| Mismatch binding ligand targets | Chemical recognition of mismatches | Affinity chromatography enrichment |
| Hg(2+) binding sites | Metal ion binding to mismatched base pairs | Probing 5-hydroxyuracil mismatches |
| Epirubicin binding sites | Preferential binding to single nucleotide mismatches | Drug-DNA interaction studies |
| Ru(bpy)2(eilatin)2+ binding sites | Binding to matched and mismatched DNA | Metal complex discrimination studies |
| DNA charge transport reporters | Sensing DNA binding events | Label-free mismatch detection |
| Isothermal titration calorimetry targets | Direct metal ion binding to mismatches | Thermodynamic binding analysis |
| Mismatch-containing duplexes | Substrate for mismatched DNA binding [5,6] | Biochemical and biophysical assays [5,6] |
How Is mismatched DNA binding Regulated?
Mismatched DNA binding is regulated at the level of protein availability and heterodimer formation, as shown by the distinct DNA binding properties of yeast Msh2-Msh6 and Mlh1-Pms1 heterodimers. The human MSH2 protein binds mismatched microsatellite DNA sequences, indicating that its mismatch binding activity is an intrinsic property that can be studied directly. Chemical conditions such as the presence of metal ions can modulate binding to mismatched base pairs, as demonstrated for Hg(2+) binding to mismatches involving 5-hydroxyuracil. Isothermal titration calorimetry has been used to detect direct metal ion binding to mismatched base pairs, highlighting that binding is sensitive to the chemical environment. Small molecules such as epirubicin hydrochloride can also interact with mismatched DNA, suggesting that exogenous compounds can influence mismatch binding equilibria.
mismatched DNA binding and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| MSH2 | Mismatch repair deficiency and cancer predisposition | MSH2 knockout cell line for mismatch binding assays |
| MSH6 | Mismatch recognition in DNA repair | MSH6 point-mutation model to test heterodimer binding |
| MLH1 | Mismatch repair heterodimer function | MLH1 knockout model for DNA binding characterization |
| PMS1 | Mismatch repair heterodimer function | PMS1 knockout model for DNA binding characterization |
| Mismatch binding ligand targets | Chemical detection of mismatched DNA | Affinity chromatography with mismatch binding ligand-Sepharose |
Mismatched DNA binding and cancer predisposition
The human MSH2 protein binds mismatched microsatellite DNA sequences, and this mismatch binding activity is directly relevant to DNA mismatch repair and genome stability. Defects in mismatch recognition are therefore linked to cancer predisposition and microsatellite instability. Yeast Msh2-Msh6 and Mlh1-Pms1 heterodimers provide model systems for dissecting the DNA binding steps that, when impaired, contribute to repair deficiency.
Chemical and pharmacological modulation of mismatch binding
Epirubicin hydrochloride preferentially binds single nucleotide mismatched DNA and can be sequestered by a mixed micelle, indicating that drug-DNA interactions at mismatches can be modulated. Ru(bpy)2(eilatin)2+ binds matched and mismatched DNA with different behavior, showing that metal complexes can discriminate mismatch sites. These findings suggest that mismatched DNA binding is a targetable interaction relevant to drug design and chemical biology [2,4].
Metal ion exposure and mismatch recognition
Hg(2+) specifically binds mismatched base pairs involving 5-hydroxyuracil in duplex DNA, linking metal ion exposure to altered mismatch recognition chemistry. Isothermal titration calorimetry can detect direct binding of metal ions to mismatched base pairs, providing a quantitative framework for studying such interactions. These observations are relevant to understanding how environmental metal ions may influence mismatch binding events [1,3].
From mismatched DNA binding-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of MSH2 abolish mismatched DNA binding? | MSH2 knockout cell line |
| How do point mutations in MSH6 affect heterodimer mismatch binding? | MSH6 point-mutation knock-in |
| Can a tagged mismatch recognition protein be tracked in live cells? | Tagged knock-in of MSH2 or MSH6 [5,6] |
| Does overexpression of a mismatch binding protein alter repair efficiency? | Overexpression cell model [5,6] |
| Can mismatch binding ligands enrich mismatched DNA from complex samples? | Mismatch binding ligand-Sepharose affinity chromatography |
| Can DNA charge transport detect mismatch binding in real time? | Electrochemical DNA charge transport sensor |
How to Study the mismatched DNA binding Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Isothermal titration calorimetry | Direct binding of metal ions to mismatched base pairs | Thermodynamic characterization of mismatch binding |
| Mismatch binding ligand-Sepharose affinity chromatography | Enrichment of mismatched DNA | Analysis of mismatched DNA in complex samples |
| DNA charge transport sensing | DNA binding events at mismatches | Label-free mismatch detection |
| Spectroscopic titration | Binding of metal complexes to matched and mismatched DNA | Discrimination studies |
| Fluorescence or absorbance assays | Binding of epirubicin to single nucleotide mismatched DNA | Drug-DNA interaction studies |
| Metal ion binding assays | Specific binding of Hg(2+) to mismatched base pairs | Probing 5-hydroxyuracil mismatches |
| Protein-DNA binding assays | Binding of MSH2 to mismatched microsatellite DNA | Mismatch recognition studies |
| Heterodimer DNA binding assays | DNA binding properties of Msh2-Msh6 and Mlh1-Pms1 | Comparative mismatch recognition studies |
Biochemical binding assays
Direct binding of proteins to mismatched DNA can be measured using purified components, as shown for the human MSH2 protein binding to mismatched microsatellite DNA sequences. Yeast Msh2-Msh6 and Mlh1-Pms1 heterodimers have been characterized for their DNA binding properties, providing a template for comparative biochemical assays. Isothermal titration calorimetry can detect direct binding of metal ions to mismatched base pairs, extending binding analysis to small molecules and ions.
Affinity chromatography and enrichment
Mismatch binding ligand-Sepharose affinity chromatography allows analysis of mismatched DNA by capturing mismatch-containing duplexes. This approach is useful for enriching mismatched DNA from complex mixtures prior to downstream analysis. The method complements solution binding assays by providing a separation-based readout of mismatched DNA binding.
Spectroscopic and electrochemical detection
Ru(bpy)2(eilatin)2+ binding to matched and mismatched DNA can be monitored spectroscopically, revealing differences in binding behavior. DNA charge transport provides a label-free electrochemical strategy to sense DNA binding events, including mismatched DNA binding. Epirubicin hydrochloride binding to single nucleotide mismatched DNA can be followed and modulated by mixed micelles, offering another optical detection route.
Metal ion binding studies
Hg(2+) specifically binds mismatched base pairs involving 5-hydroxyuracil in duplex DNA, providing a chemical probe for mismatch recognition. Isothermal titration calorimetry is emphasized as a method for detecting direct binding of metal ions to mismatched base pairs. These approaches are valuable for understanding how environmental or therapeutic metal ions interact with mismatched DNA [1,3].
How CRISPR Can Be Used to Study GO:0030983 mismatched DNA binding
Knockout
Knockout of mismatch recognition genes such as MSH2 can be used to test whether mismatched DNA binding is abolished in cells, building on the demonstrated binding of human MSH2 to mismatched microsatellite DNA sequences. Yeast Msh2-Msh6 and Mlh1-Pms1 heterodimers provide a model for interpreting loss-of-function phenotypes after gene knockout.
Point Mutation
Point mutations in mismatch recognition domains can be introduced to dissect which residues are required for mismatched DNA binding, guided by the DNA binding properties of Msh2-Msh6 and Mlh1-Pms1 heterodimers. Such models help separate binding defects from other functions of the same protein.
Knock-in
Tagged knock-in of mismatch recognition proteins allows tracking of their localization and interaction with mismatched DNA in cells, extending biochemical findings on MSH2 mismatch binding. Knock-in of disease-associated variants can be used to test whether altered mismatched DNA binding contributes to repair deficiency [5,6].
Overexpression
Overexpression of mismatch binding proteins can be used to test whether increased protein levels enhance mismatched DNA binding or alter repair outcomes, based on the intrinsic mismatch binding activity of MSH2. Overexpression models also facilitate purification of proteins for biochemical binding assays [5,6].
How EDITGENE Supports mismatched DNA binding Research
Researchers studying mismatched DNA binding-related genes often need to determine whether a candidate gene is causally involved in mismatch recognition, repair, or chemical detection. EDITGENE provides CRISPR-based cell models and screening services that allow precise interrogation of genes such as MSH2, MSH6, MLH1, and PMS1 in the context of GO:0030983 [5,6].
Contact EDITGENE today to design your custom CRISPR model for mismatched DNA binding research.
Frequently Asked Questions About mismatched DNA binding
What is mismatched DNA binding?
Mismatched DNA binding is the molecular function of binding to a double-stranded DNA region containing one or more mismatches, as defined by GO:0030983.
What genes are involved in mismatched DNA binding?
Genes encoding mismatch recognition proteins include MSH2, MSH6, MLH1, and PMS1, based on studies of human MSH2 and yeast Msh2-Msh6 and Mlh1-Pms1 heterodimers [5,6].
How is mismatched DNA binding detected?
It can be detected by biochemical binding assays, mismatch binding ligand-Sepharose affinity chromatography, isothermal titration calorimetry, and DNA charge transport sensing [3,7,8].
Why is mismatched DNA binding important for cancer research?
Human MSH2 binds mismatched microsatellite DNA sequences, and defects in mismatch recognition are linked to genome instability and cancer predisposition.
Can small molecules bind mismatched DNA?
Yes, epirubicin hydrochloride preferentially binds single nucleotide mismatched DNA, and Ru(bpy)2(eilatin)2+ binds matched and mismatched DNA with different behavior [2,4].
Do metal ions bind mismatched DNA?
Hg(2+) specifically binds mismatched base pairs involving 5-hydroxyuracil, and isothermal titration calorimetry can detect direct metal ion binding to mismatched base pairs [1,3].
What is the GO ID for mismatched DNA binding?
The GO ID is GO:0030983, with synonyms mispair binding and mispaired DNA binding.
What proteins recognize mismatched DNA in yeast?
Yeast Msh2-Msh6 and Mlh1-Pms1 heterodimers have been characterized for their DNA binding properties.
How can mismatched DNA be enriched for analysis?
Mismatch binding ligand-Sepharose affinity chromatography can be used to analyze and enrich mismatched DNA.
Is mismatched DNA binding label-free detectable?
Yes, DNA charge transport provides a label-free approach to sensing DNA binding events at mismatches.
Conclusion
GO:0030983 mismatched DNA binding is a molecular function that underlies mismatch recognition in DNA repair and enables chemical and electrochemical detection of mispaired duplexes [5,6,7,8]. The human MSH2 protein binds mismatched microsatellite DNA sequences, and yeast Msh2-Msh6 and Mlh1-Pms1 heterodimers provide tractable models for studying this binding activity [5,6]. Small molecules and metal ions can also engage mismatched DNA, expanding the relevance of this term to chemical biology and biosensing [1,2,3,4]. Researchers can now combine biochemical assays, affinity chromatography, calorimetry, and DNA charge transport to interrogate mismatched DNA binding with high precision [3,7,8].
References
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- 2. Khamari L et al.. 2021. Preferential Binding of Epirubicin Hydrochloride with Single Nucleotide Mismatched DNA and Subsequent Sequestration by a Mixed Micelle.. J Phys Chem B 125(42):11660-11672 PMID: 34652157
- 3. Torigoe H et al.. 2023. Importance of isothermal titration calorimetry for the detection of the direct binding of metal ions to mismatched base pairs in duplex DNA.. Dalton Trans 52(37):13089-13096 PMID: 37661915
- 4. Zeglis BM et al.. 2008. Binding of Ru(bpy)2(eilatin)2+ to matched and mismatched DNA.. Inorg Chem 47(14):6452-7 PMID: 18576614
- 5. Fishel R et al.. 1994. Binding of mismatched microsatellite DNA sequences by the human MSH2 protein.. Science 266(5189):1403-5 PMID: 7973733
- 6. Drotschmann K et al.. 2002. DNA binding properties of the yeast Msh2-Msh6 and Mlh1-Pms1 heterodimers.. Biol Chem 383(6):969-75 PMID: 12222686
- 7. Goto Y et al.. 2007. Analysis of mismatched DNA by mismatch binding ligand (MBL)-Sepharose affinity chromatography.. Anal Bioanal Chem 388(5-6):1165-73 PMID: 17541568
- 8. Zwang TJ et al.. 2018. Sensing DNA through DNA Charge Transport.. ACS Chem Biol 13(7):1799-1809 PMID: 29790735
