Abstract
The Escherichia coli replisome contains three polymerases, one more than necessary to duplicate the two parental strands. Using single-molecule studies, we reveal two advantages conferred by the third polymerase. First, dipolymerase replisomes are inefficient at synthesizing lagging strands, leaving single-strand gaps, whereas tripolymerase replisomes fill strands almost to completion. Second, tripolymerase replisomes are much more processive than dipolymerase replisomes. These features account for the unexpected three-polymerase-structure of bacterial replisomes.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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DNA Polymerase III / chemistry
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DNA Polymerase III / metabolism*
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DNA Replication*
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DNA, Bacterial / chemistry
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DNA, Bacterial / genetics
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DNA, Bacterial / metabolism
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Escherichia coli / enzymology
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Escherichia coli / genetics
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Escherichia coli Proteins / chemistry
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Escherichia coli Proteins / metabolism*
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Models, Genetic
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Models, Molecular
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Multienzyme Complexes / metabolism*
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Nucleic Acid Conformation
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Protein Binding
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Protein Structure, Tertiary
Substances
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DNA, Bacterial
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Escherichia coli Proteins
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Multienzyme Complexes
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DNA polymerase III, alpha subunit
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DNA Polymerase III
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dnaQ protein, E coli