GO:0106377 2-hydroxy-ATP hydrolase activity

GO:0106377, 2-hydroxy-ATP hydrolase activity, is a molecular function defined by the reaction 2-hydroxy-ATP + H2O = 2-hydroxy-AMP + H+ + diphosphate. This activity belongs to the family of nucleotide hydrolases that remove oxidized or otherwise damaged nucleotides from the cellular pool, thereby preventing their incorporation into DNA or RNA. The reaction specifically targets 2-hydroxy-ATP, an oxidized form of ATP, and converts it to 2-hydroxy-AMP and diphosphate. Because oxidized nucleotides can mispair during replication and transcription, enzymes with this activity are central to nucleotide pool sanitation and genome maintenance. The human enzyme MTH1 (also known as NUDT1) is the prototypical protein that hydrolyzes 2-hydroxy-ATP, and its ability to act on this substrate has been directly demonstrated in biochemical assays. MTH1 is a MutT homolog, and its broader substrate repertoire includes other oxidized nucleotides such as 8-chloro-dGTP, underscoring its role in defending against diverse nucleotide lesions. Researchers studying oxidative stress, cancer metabolism, and DNA repair frequently encounter this activity because it sits at the interface of nucleotide metabolism and genome stability. Understanding GO:0106377 therefore provides a molecular entry point into how cells manage oxidative damage at the nucleotide level.

In our own words, GO:0106377 describes the catalytic activity of an enzyme that uses water to cleave 2-hydroxy-ATP into 2-hydroxy-AMP and diphosphate, releasing a proton. This is a hydrolytic reaction that belongs to the broader class of nucleotide triphosphate hydrolases, and it specifically recognizes an oxidized adenine nucleotide as its substrate. The activity is defined by its substrate specificity and products rather than by a single protein, meaning any enzyme that catalyzes this exact reaction can be annotated with GO:0106377.

GO:0106377 is important because it represents a direct enzymatic defense against oxidized nucleotides, which are generated under conditions of oxidative stress and can cause mutations if incorporated into DNA or RNA. The human enzyme MTH1 hydrolyzes 2-hydroxy-ATP, and this activity helps maintain the integrity of the nucleotide pool by eliminating a potentially mutagenic substrate. Because MTH1 also acts on other oxidized nucleotides such as 8-chloro-dGTP, the activity contributes to a broad sanitizing function that supports genome stability. Dysregulation of this activity has been linked to cancer biology, where cancer cells may rely on MTH1 to survive oxidative stress. Consequently, measuring and manipulating 2-hydroxy-ATP hydrolase activity is relevant for understanding mutagenesis, cancer cell vulnerabilities, and the cellular response to oxidative damage.

The following genes and proteins are directly or functionally linked to 2-hydroxy-ATP hydrolase activity (GO:0106377) based on published biochemical evidence.

The activity of 2-hydroxy-ATP hydrolase is primarily regulated at the level of MTH1 expression and protein stability, although direct allosteric regulation has not been extensively characterized. MTH1 expression can be induced by oxidative stress, and its promoter contains response elements that respond to cellular redox status. Post-translational modifications may also affect MTH1 activity or localization, but these mechanisms require further study. Because MTH1 also acts on other oxidized nucleotides such as 8-chloro-dGTP, its overall cellular impact is influenced by the spectrum of damaged nucleotides present. Researchers should consider both transcriptional and post-transcriptional regulation when designing experiments to modulate this activity.

Cancer cells often exhibit elevated oxidative stress and may become dependent on MTH1 to sanitize oxidized nucleotides, including 2-hydroxy-ATP. Knockdown or inhibition of MTH1 can reduce cancer cell viability, suggesting that 2-hydroxy-ATP hydrolase activity contributes to tumor survival. This has made MTH1 a candidate target for anticancer therapy, particularly in tumors with high reactive oxygen species levels.

Oxidative damage is a hallmark of neurodegenerative diseases, and MTH1 may protect neurons by hydrolyzing oxidized nucleotides such as 2-hydroxy-ATP. Loss of MTH1 function could exacerbate neuronal vulnerability to oxidative stress, although direct evidence in human neurodegeneration is still emerging. Model systems using MTH1 knockout or overexpression can help clarify its protective role.

Accumulation of oxidized nucleotides is associated with aging, and MTH1-mediated hydrolysis of 2-hydroxy-ATP may help maintain genome stability over time. Reduced MTH1 activity could lead to increased mutation load and cellular senescence. Studying this activity in aging models may reveal mechanisms of age-related decline.

Direct measurement of 2-hydroxy-ATP hydrolase activity can be performed using purified enzyme and substrate, followed by detection of products via HPLC or mass spectrometry. These assays are essential for confirming that a candidate protein carries GO:0106377 activity. They can also be used to screen for inhibitors or to compare mutant enzymes.

CRISPR knockout screens can identify genes that modulate sensitivity to oxidative stress or that are synthetic lethal with MTH1 loss. Such screens help place 2-hydroxy-ATP hydrolase activity within cellular networks. Libraries targeting nucleotide metabolism genes are particularly useful.

RNA-seq and proteomics can reveal changes in gene expression and protein abundance upon MTH1 knockout or overexpression. These approaches help identify pathways that compensate for loss of 2-hydroxy-ATP hydrolase activity. They also provide insights into oxidative stress response networks.

Fluorescence microscopy of tagged MTH1 can reveal its subcellular localization and dynamics. This is important because 2-hydroxy-ATP hydrolase activity may be needed in specific compartments such as mitochondria or nucleus. Live-cell imaging can track responses to oxidative stress.

Researchers studying 2-hydroxy-ATP hydrolase activity-related genes often need to determine whether a candidate gene is causally involved in oxidative stress resistance, genome stability, or cancer cell survival. EDITGENE provides a comprehensive suite of CRISPR-based services to generate precisely engineered cell models for such investigations.

GO:0106377, 2-hydroxy-ATP hydrolase activity, represents a critical enzymatic defense against oxidized nucleotides, with human MTH1 as the primary enzyme responsible for this reaction. Its ability to hydrolyze 2-hydroxy-ATP and other damaged nucleotides underscores its importance in genome stability and oxidative stress responses. Continued research using CRISPR-engineered cell models will further clarify its roles in cancer, neurodegeneration, and aging.