The Escherichia coli preprimosome and DNA B helicase can form replication forks that move at the same rate Journal Article


Authors: Mok, M.; Marians, K. J.
Article Title: The Escherichia coli preprimosome and DNA B helicase can form replication forks that move at the same rate
Abstract: A DNA replication system was developed that could generate rolling-circle DNA molecules in vitro in amounts that permitted kinetic analyses of the movement of the replication forks. Two artificial primer-template DNA substrates were used to study DNA synthesis catalyzed by the DNA polymerase III holoenzyme in the presence of either the preprimosomal proteins (the primosomal proteins minus the DNA G primase) and the Escherichia coli single-stranded DNA binding protein or the DNA B helicase alone. Helicase activities have recently been demonstrated to be associated with the primosome, a mobile multiprotein priming apparatus that requires seven E. coli proteins (replication factor Y (protein n'), proteins n and n'', and the products of the dnaB, dnaC, dnaG, and dnaT genes) for assembly, and with the DNA B protein. Consistent with a rolling-circle mechanism in which a helicase activity permitted extensive (-) strand DNA synthesis on a (+) single-stranded, circular DNA template, the major DNA products formed were multigenome-length, single-stranded, linear molecules. The replication forks assembled with either the preprimosome or the DNA B helicase moved at the same rate (approximately 730 nucleotides/s) at 30 degrees C and possessed apparent processivities in the range of 50,000-150,000 nucleotides. The single-stranded DNA binding protein was not required to maintain this high rate of movement in the case of leading strand DNA synthesis catalyzed by the DNA polymerase III holoenzyme and the DNA B helicase.
Keywords: dna replication; metabolism; enzymology; biosynthesis; bacterial protein; bacterial proteins; kinetics; escherichia coli; restriction endonuclease; helicase; conformation; nucleic acid conformation; bacterial dna; dna, bacterial; dna helicases; dna template; dna directed dna polymerase gamma; templates, genetic; type ii site specific deoxyribonuclease; dna polymerase iii; article; dna restriction enzymes; deoxyribonuclease bamhi
Journal Title: Journal of Biological Chemistry
Volume: 262
Issue: 34
ISSN: 0021-9258
Publisher: American Society for Biochemistry and Molecular Biology  
Date Published: 1987-12-05
Start Page: 16644
End Page: 16654
Language: English
PUBMED: 2824502
PROVIDER: scopus
DOI: 10.1016/S0021-9258(18)49304-0
DOI/URL:
Notes: Article -- Export Date: 5 February 2021 -- Source: Scopus
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MSK Authors
  1. Kenneth Marians
    137 Marians