Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0344329 (collapse)
 28,634 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

p53R2 is a newly identified small subunit of ribonucleotide reductase (RR) and plays a key role in supplying precursors for DNA repair in a p53-dependent manner. Currently, we are studying the redox property, structure, and function of p53R2. In cell-free systems, p53R2 did not oxidize a reactive oxygen species (ROS) indicator carboxy-H2DCFDA, but another class I RR small subunit, hRRM2, did. Further studies showed that purified recombinant p53R2 protein has catalase activity, which breaks down H2O2. Overexpression of p53R2 reduced intracellular ROS and protected the mitochondrial membrane potential against oxidative stress, whereas overexpression of hRRM2 did not and resulted in a collapse of mitochondrial membrane potential. In a site-directed mutagenesis study, antioxidant activity was abrogated in p53R2 mutants Y331F, Y285F, Y49F, and Y241H, but not Y164F or Y164C. The fluorescence intensity in mutants oxidizing carboxy-H2DCFDA, in order from highest to lowest, was Y331F > Y285F > Y49F > Y241H > wild-type p53R2. This indicates that Y331, Y285, Y49, and Y241 in p53R2 are critical residues involved in scavenging ROS. Of interest, the ability to oxidize carboxy-H2DCFDA indicated by fluorescence intensity was negatively correlated with RR activity from wild-type p53R2, mutants Y331F, Y285F, and Y49F. Our findings suggest that p53R2 may play a key role in defending oxidative stress by scavenging ROS, and this antioxidant property is also important for its fundamental enzymatic activity.
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PMID:Structurally dependent redox property of ribonucleotide reductase subunit p53R2. 1648 86

Human ribonucleotide reductase (RR) small subunits, M2 and P53R2, play key roles in forming RR holoenzyme and supplying nucleotide precursors for DNA replication and repair. Currently, we are studying the redox property, structure, and function of hRRM2 and p53R2. In the cell-free system, p53R2 did not oxidize a reactive oxygen species (ROS) indicator Carboxy-H(2)DCFDA, but hRRM2 did. Further studies demonstrated that purified recombinant p53R2 protein has the catalase activity to scavenge H(2)O(2). Over-expression of p53R2 reduced intracellular ROS and protected the mitochondrial membrane potential against oxidative stress, whereas over-expression of hRRM2 did not result in the collapse of mitochondrial membrane potential. Our findings suggest that p53R2 may play a key role in defending oxidative stress by scavenging ROS, and this antioxidant property is also important for its enzymatic activity.
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PMID:Redox property of ribonucleotide reductase small subunit M2 and p53R2. 1908 48