The multistage model of carcinogenesis states that an accumulation of mutations in genes that are important for maintaining cellular homeostasis may lead to cancer. A specific type of mutation observed in particular types of cancer is the CC-->TT mutation found in the TP53 gene of patients with basal or squamous...
Natural products from plants, bacteria, and fungi play an important role in society. Over the last 35 years, natural products and their derivatives have inspired over 60% of all FDA approved small-molecule drugs, and are among the top prescribed therapeutics.1-2 Fleming’s discovery of the fungal antibiotic penicillin started the “Golden...
PCR-based codon-specific random mutagenesis and site-specific mutagenesis were performed to construct a library of 18 amino acid changes at Arg276 in the conserved leucine-loop of the core catalytic domain of human uracil-DNA glycosylase (UNG). Each Arg276 mutant was then overproduced in E. coli cells and purified to apparent homogeneity by...
DNA damage, if not repaired, can become a mutation. Mutation
accumulation is associated with initiation and progression of tumorigenesis. DNA
mismatch repair (MMR) is required for maintaining genetic stability by repairing
replication errors. Biochemical studies have shown that MMR also recognizes
mismatch-causing DNA lesions, suggesting the role of MMR in...
Intracellular dNTP pool sizes are highly asymmetric, with dGTP usually comprising 5 to 10% of the sum of the dNTP pools. The work presented in this dissertation addresses the question of whether the underrepresentation of dGTP is related to its potential to be oxidized by reactive oxygen species. 8-oxo-guanine is...
Two strains of Escherichia coli were studied to determine the effect of constitutive expression of the SOS DNA damage repair response on the activity of ribonucleotide reductase. Activity of the reductase and cellular deoxynucleoside triphosphate (dNTP) pools were both determined before and after exposure of the cells to ultraviolet radiation....
The DNA-binding domains of E. coli uracil-DNA glycosylase (Ung) and human replication protein A (hRPA) were studied using a general protocol developed in our laboratory for probing protein-DNA interactions. The procedure involves purification and mass spectrometric analysis of the nucleopeptide-products of a tryptically digested UV-crosslinked protein-nucleic acid complex. In the...