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)

A group of proteins that act as primers for initiation of linear DNA replication are called DNA-terminal proteins (terminal proteins). We have found a short stretch of conserved amino acid sequence among the terminal proteins from six different sources. The location of this sequence motif is also similar among the different terminal-proteins. To determine the functional role of this terminal-protein domain in DNA replication, we have studied the bacteriophage PRD1 system. The PRD1 terminal protein and DNA polymerase genes were cloned into expression vectors, and the recombinant plasmids were used for constructing PRD1 terminal protein mutants. Site-directed mutagenesis and functional analysis showed that one of the two arginines (Arg-174) in the conserved sequence is critical for the initiation complex-forming activity of the PRD1 terminal protein. Replacement of Arg-174 by noncharged amino acids resulted in nonfunctional terminal protein. Phenylglyoxal, an alpha-dicarbonyl compound that reacts with the guanidino group of arginine, inhibits initiation complex formation between PRD1 terminal protein and dGMP. On the basis of these results, we propose that Arg-174 represents, at least in part, the binding site for phosphate groups of dGTP.
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PMID:An essential arginine residue for initiation of protein-primed DNA replication. 223 78

Phenylglyoxal, an arginine-specific reagent, strongly inhibits DNA polymerases isolated from eukaryotic, prokaryotic, and RNA tumor viral sources as well as Escherichia coli RNA polymerase. The inhibitory action of phenylglyoxal appears to be due to interference with the template binding function of these enzymes and implies the presence of an arginine residue at the template binding site of these enzymes from diverse sources and suggests that template dependent DNA, and perhaps RNA polymerases, may be mechanistically similar with respect to their template binding function. In contrast, the activity of terminal deoxynucleotidyl-transferase, a template-independent DNA polymerase isolated from calf thymus, is not inhibited by phenylglyoxal. A detailed analysis of the inhibitory process carried out using avian myeloblastosis virus (AMV) DNA polymerase as a test enzyme revealed that inclusion of template-primer during the preincubation with phenylglyoxal, but not substrate triphosphates or primer alone, protects the enzyme against phenylglyoxal inactivation. Furthermore, phenylglyoxal does not appear to inhibit the elongation of initiated DNA strands, but blocks the reinitiation of DNA synthesis.
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PMID:Phenylglyoxal as a template site-specific reagent for DNA and RNA polymerases. Selective inhibition of initiation. 698 8