Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.7 (DNA polymerase)
 17,007 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The rat mitochondrial single strand DNA binding protein (SSB) P16 was purified to apparent homogeneity by elution from single strand DNA agarose with ethidium bromide. Each monomer of P16 contains two tryptophan residues, and the intrinsic fluorescence from these residues is quenched upon binding to single strand polynucleotides. From fluorescence quench titrations of ligand to fixed amounts of DNA lattice, a binding site size of 8 or 9 nucleotides per P16 monomer was found. Measurement of the affinity of P16 for isolated sites by titration with either oligo(dT)8 or 5'-dephosphorylated oligo(dT)8 indicated values on the order of 10(7) M-1. P16 exhibited a binding preference for single strand DNA, poly(dT), and poly(dC) in comparison to double strand DNA, poly(U), or poly[d(A-T)]. Although it was not possible to show that P16 destabilizes double helical DNA or even poly[d(A-T)], binding of P16 does inhibit the process of renaturation as shown by inhibition of duplex formation between poly(dA) and poly(dT). The binding of saturating amounts of P16 to single strand poly(dT).oligo(dA)50 template-primers enhanced approximately 10-fold the activity of both the homologous mitochondrial DNA polymerase and the Escherichia coli DNA polymerase I Klenow fragment. However, the mitochondrial DNA primase was nearly completely inhibited by the saturation of the poly(dT) template with P16. Amino-terminal sequence analysis of P16 and a protease-insensitive, DNA binding domain (Mr approximately 6000) revealed that the DNA binding domain residues, at least in part, in the amino-terminal third of the P16 molecule. Furthermore, the amino-terminal sequence was found to be strikingly similar to that of the Xenopus laevis mtSSB-1 and to a lesser extent similar to E. coli SSB and E. coli F sex factor SSB.
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PMID:Structural and functional studies of the rat mitochondrial single strand DNA binding protein P16. 222 14

Most DNA polymerases interact with their cognate processive replication factor through a small peptide, this interaction being absolutely required for their function in vivo. We have solved the crystal structure of a complex between the beta sliding clamp of Escherichia coli and the 16 residue C-terminal peptide of Pol IV (P16). The seven C-terminal residues bind to a pocket located at the surface of one beta monomer. This region was previously identified as the binding site of another beta clamp binding protein, the delta subunit of the gamma complex. We show that peptide P16 competitively prevents beta-clamp-mediated stimulation of both Pol IV and alpha subunit DNA polymerase activities, suggesting that the site of interaction of the alpha subunit with beta is identical with, or overlaps that of Pol IV. This common binding site for delta, Pol IV and alpha subunit is shown to be formed by residues that are highly conserved among many bacterial beta homologs, thus defining an evolutionarily conserved hydrophobic crevice for sliding clamp ligands and a new target for antibiotic drug design.
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PMID:Structural and biochemical analysis of sliding clamp/ligand interactions suggest a competition between replicative and translesion DNA polymerases. 1472 36

Aberrant DNA methylation of CpG site in the gene promoter region has been confirmed to be closely associated with carcinogenesis. In this present study, a new method based on the allele-specific extension on microarray technique for detecting changes of DNA methylation in cancer was developed. The target gene regions were amplified from the bisulfite treated genomic DNA (gDNA) with modified primers and treated with exonuclease to generate single-strand targets. Allele-specific extension of the immobilized primers took place along a stretch of target sequence with the presence of DNA polymerase and Cy5-labeled dGTP. To control the false positive signals, the hybridization condition, DNA polymerase, extension time and primers design were optimized. Two breast tumor-related genes (P16 and E-cadherin) were analyzed with this present method successfully and all the results were compatible with that of traditional methylation-specific PCR. The experiments results demonstrated that this DNA microarray-based method could be applied as a high throughput tool for methylation status analysis of the cancer-related genes, which could be widely used in cancer diagnosis or the detection of recurrence.
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PMID:Allele-specific extension on microarray for DNA methylation analysis. 1796 40