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.
AUTOR(ES)
Charette, M F
RESUMO
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.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=339777Documentos Relacionados
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