Deoxyribonuclease I, commonly known as DNase I, is a fundamental enzyme utilized in molecular biology laboratories. This enzyme breaks down DNA molecules, making it an indispensable tool for various scientific investigations. New England Biolabs (NEB) provides high-quality DNase I products to researchers worldwide, supporting applications from purifying genetic material to preparing samples for advanced sequencing technologies.
Understanding DNase I
DNase I is an endonuclease, an enzyme that degrades DNA by cleaving the phosphodiester bonds within the DNA backbone. This action breaks down larger DNA molecules into smaller fragments, typically di-, tri-, and oligonucleotide products with specific phosphorylated and hydroxylated ends. The enzyme acts non-specifically on DNA sequences, meaning it does not target particular genetic codes.
DNase I is found in various organisms, including mammals, where it plays roles in processes like the digestion of nucleic acids in the gastrointestinal tract and the breakdown of DNA from dying cells for removal. It acts on both single- and double-stranded DNA, as well as chromatin and RNA:DNA hybrids. The enzyme’s activity requires the presence of metal ions, such as magnesium and calcium, for optimal function.
Key Applications in Scientific Research
DNase I is used in RNA purification to remove contaminating DNA from RNA samples. This step is important for techniques sensitive to DNA contamination, such as reverse transcription quantitative polymerase chain reaction (RT-qPCR), RNA sequencing, and microarray analysis. Ensuring RNA samples are DNA-free allows for accurate gene expression studies.
DNase I also plays a role in DNA fragmentation, breaking down large genomic DNA into smaller, more manageable pieces. This fragmentation is a necessary step for preparing DNA libraries for next-generation sequencing (NGS), where uniform fragment sizes are preferred for efficient sequencing. It is also employed in techniques like DNA footprinting, which helps identify protein-binding sites on DNA by observing patterns of protection from DNase I digestion.
DNase I is used to reduce the viscosity of cell lysates during protein purification or cellular fractionation. Cells contain highly concentrated chromosomal DNA, which can make lysates very viscous and difficult to handle. Degrading this DNA with DNase I significantly reduces viscosity, facilitating downstream separation and purification processes.
Why NEB’s DNase I Stands Out
New England Biolabs’ DNase I products, such as DNase I (RNase-free) (M0303S/L) and RQ1 RNase-Free DNase I, are favored by researchers due to their high purity and consistent performance. They are certified as RNase-free, meaning they are rigorously tested to ensure the absence of ribonuclease contamination. This purity is important in RNA-sensitive applications, as even trace amounts of RNases can degrade precious RNA samples.
NEB’s DNase I is isolated from a recombinant source, contributing to its consistent quality across different batches. The enzyme is supplied with a 10X reaction buffer, simplifying experimental setup. NEB provides formulations optimized for specific applications, including versions with or without magnesium chloride. Heat inactivation at 75°C for 10 minutes allows for easy removal of the enzyme from samples, preventing further DNA degradation after the desired reaction is complete. These attributes collectively contribute to the reliability and success of various molecular biology workflows.