Endonuclease Assays
Endonuclease Assays - Related Videos
11:53
Substrate Generation for Endonucleases of CRISPR/Cas Systems
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Cited by 4 •
2012
CRISPR/Cas systems mediate adaptive immunity in Bacteria and Archaea. Many Cas proteins are proposed to act as endoribonucleases acting on crRNA precursors of varying length. Here we illustrate three different approaches to generate pre-crRNA substrates for the biochemical analysis of Cas endonuclease activity.
09:40
Quantitation and Analysis of the Formation of HO-Endonuclease Stimulated Chromosomal Translocations by Single-Strand Annealing in Saccharomyces cerevisiae
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Cited by 9 •
2011
The HO-stimulated translocation assay monitors single-strand annealing following the creation of DNA double-strand breaks at multiple loci in diploid Saccharomyces cerevisiae. This mechanism may model genome rearrangements in somatic cells of higher eukaryotes following exposure to high doses of ionizing radiation.
06:07
Continuous Fluorescence-Based Endonuclease-Coupled DNA Methylation Assay to Screen for DNA Methyltransferase Inhibitors
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2022
DNA methyltransferases are potential cancer drug targets. Here, a protocol is presented to assess small molecules for DNA methyltransferase inhibition. This assay utilizes an endonuclease to couple DNA methylation to fluorescence generation and allows for enzyme activity to be monitored in real...
09:16
In Vitro Directed Evolution of a Restriction Endonuclease with More Stringent Specificity
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2020
Restriction endonucleases with new sequence specificity can be developed from enzymes recognizing a partially degenerate sequence. Here we provide a detailed protocol that we successfully used to alter the sequence specificity of NlaIV enzyme. Key ingredients of the protocol are the in vitro compartmentalization of the transcription/translation reaction and selection of variants with new sequence specificities.
10:59
Visualizing and Quantifying Endonuclease-Based Site-Specific DNA Damage
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Cited by 3 •
2021
This article introduces essential steps of immunostaining and chromatin immunoprecipitation. These protocols are commonly used to study DNA damage-related cellular processes and to visualize and quantify the recruitment of proteins implicated in DNA repair.
FAQs
Cleavage patterns depend on more than enzyme concentration: substrate sequence, nucleic acid structure, and chemical modifications can alter whether and where phosphodiester bonds are cut. By comparing products from deliberately varied substrates, researchers can identify preferences that reveal substrate specificity. This approach is useful for determining how an endonuclease recognizes DNA or RNA features.
Reaction requirements are tested by changing experimental conditions while keeping the substrate and enzyme comparison consistent. Measuring activity under those conditions can show which requirements support catalysis, whereas reduced cleavage can indicate inhibition. Endonuclease assays therefore connect an observed change in cleavage with a specific condition, rather than treating activity as an unexplained property.
The readout determines how cleavage is interpreted. A shift in electrophoretic pattern or fragment size directly indicates a different product distribution, while fluorescence or absorbance reports a measurable change associated with the reaction. Examining cleavage products across conditions helps distinguish altered activity from changes in substrate sequence, structure, or chemical modification.
A practical workflow begins by selecting a defined DNA or RNA substrate and combining it with purified endonuclease under controlled conditions. Researchers then compare the reaction with relevant altered conditions or substrates and detect cleavage through fragment size, fluorescence, absorbance, or electrophoresis. Consistent comparison of these outputs supports evaluation of activity, specificity, and inhibition.
Researchers apply Endonuclease Assays when they need a controlled measurement of nucleic-acid cleavage rather than only a qualitative description of enzyme behavior. In biology, the results support investigations of DNA and RNA structure, repair, and degradation. The same measurements can contribute to studies of genome stability and molecular biology.
Results can guide biotechnology and therapeutic-development studies by showing whether sequence, structure, or chemical modification changes cleavage. A comparison of products across conditions provides evidence for characterizing enzyme behavior, while inhibition measurements can identify conditions that suppress activity. The assay therefore links molecular observations to broader studies of nucleic-acid processing.