Ribonucleotide reductases (RNRs) transform RNA building blocks to DNA building blocks by catalyzing the substitution of the 2'OH-group of a ribonucleotide with a hydrogen by a mechanism involving protein radicals. Three classes of RNRs employ different mechanisms for the generation of the protein radical. Recent structural studies of members from each class have led to a deeper understanding of their catalytic mechanism and allosteric regulation by nucleoside triphosphates. The main emphasis of this review is on regulation of RNR at the molecular and cellular level. Conformational transitions induced by nucleotide binding determine the regulation of substrate specificity. An intricate interplay between gene activation, enzyme inhibition, and protein degradation regulates, together with the allosteric effects, enzyme activity and provides the appropriate amount of deoxynucleotides for DNA replication and repair. In spite of large differences in the amino acid sequences, basic structural features are remarkably similar and suggest a common evolutionary origin for the three classes.
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http://dx.doi.org/10.1146/annurev.biochem.75.103004.142443 | DOI Listing |
Mitochondrial retrograde signaling (MRS) pathways relay the functional status of mitochondria to elicit homeostatic or adaptive changes in nuclear gene expression. Budding yeast have "intergenomic signaling" pathways that sense the amount of mitochondrial DNA (mtDNA) independently of oxidative phosphorylation (OXPHOS), the primary function of genes encoded by mtDNA. However, MRS pathways that sense the amount of mtDNA in mammalian cells remain poorly understood.
View Article and Find Full Text PDFis a major contributor to infections in humans and is widely distributed in the environment. It is capable of aerobic and anaerobic growth, providing adaptability to environmental changes and in confronting immune responses. We applied high-throughput native 2-dimensional metalloproteomics to under oxic and anoxic conditions.
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January 2025
Department of Emergency Medicine, Hengyang Medical School, The Affiliated Changsha Central Hospital, University of South China, Changsha, Hunan, China.
Our study aims to investigate the role of pyrimidine metabolism in prostate cancer and its associations with the immune microenvironment, drug sensitivity, and tumor mutation burden. Through transcriptomic and single-cell RNA sequencing analyses, we explored metabolic pathway enrichment, immune infiltration patterns, and differential gene expression in prostate cancer samples. The results showed that pyrimidine metabolism-related genes were significantly upregulated in the P2 subgroup compared to the P1 subgroup, with enhanced metabolic activity observed in basal and luminal epithelial cells.
View Article and Find Full Text PDFGenes (Basel)
December 2024
State Key Lab of Pharmaceutical Biotechnology (SKLPB), College of Life Sciences in Nanjing University (Xianlin Campus), Nanjing University, Nanjing 210046, China.
Background: Hepatocellular carcinoma (HCC) is a type of malignant tumor with high morbidity and mortality. Untimely treatment and high recurrence are currently the major challenges for HCC. The identification of potential targets of HCC progression is crucial for the development of new therapeutic strategies.
View Article and Find Full Text PDFIn Saccharomyces cerevisiae cells, the bulk of mitochondrial DNA (mtDNA) replication is mediated by the replicative high-fidelity DNA polymerase γ. However, upon UV irradiation low-fidelity translesion polymerases: Polη, Polζ and Rev1, participate in an error-free replicative bypass of UV-induced lesions in mtDNA. We analysed how translesion polymerases could function in mitochondria.
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