title: Persistence of DNA synthesis arrest sites in the presence of T4 DNA polymerase and T4 gene 32, 44, 45 and 62 DNA polymerase accessory proteins.
abstract: DNA synthesis by phage T4 DNA polymerase is arrested at specific sequences in single-stranded DNA templates. To determine whether or not T4 DNA polymerase accessory proteins 32, 44, 45 and 62 eliminated recognition of these arrest sites, unique primer-templates were constructed in which DNA synthesis began at a DNA primer located at different distances from palindromic and nonpalindromic arrest sites. Nucleotide positions that caused polymerase to pause or leave the template were identified by sequence analysis of 5'-end labeled nascent DNA chains. Stable hairpin structures at palindromic sequences were confirmed by acetylation of single-stranded sequences with bromoacetaldehyde. Our results confirmed that these T4 DNA polymerase accessory proteins stimulated T4 DNA polymerase activity and processivity on natural as well as homopolymer primer-templates. However, they did not alter recognition of DNA synthesis arrest sites by T4 DNA polymerase. Extensive DNA synthesis resulted from an increased rate of translocation and/or processivity to the same extent over all DNA sequences.
mesh_terms: D004261:DNA Replication; D004279:DNA, Viral / Q000302:isolation & purification; D004259:DNA-Directed DNA Polymerase / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D005796:Genes; D005814:Genes, Viral; D007700:Kinetics; D008970:Molecular Weight; D013604:T-Phages / Q000201:enzymology / Q000235:genetics*; D013698:Templates, Genetic; D014764:Viral Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D004279:DNA, Viral; D014764:Viral Proteins; D004259:DNA-Directed DNA Polymerase