Abstract
The determination of the structure of the processivity factor (beta subunit) of Escherichia coli DNA polymerase III holoenzyme showed that this protein acts to clamp the polymerase onto DNA by forming a closed circular structure that can encircle duplex DNA (X.-P. Kong, R. Onrust, M. O'Donnell & J. Kuriyan. (1992). Cell, 69, 425-437). In this review we describe the features of the beta subunit that allow it to be linked tightly but non-specifically to DNA, and discuss the surprisingly symmetrical architecture of the molecule. The simple repeating pattern of the chain fold allows a connection to be made to the as yet unknown structures of eukaryotic proliferating cell nuclear antigen and the gene 45 protein of bacteriophage T4, which are the processivity factors of the corresponding DNA polymerases.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
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Review
MeSH terms
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Adenosine Triphosphatases / chemistry
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Adenosine Triphosphatases / metabolism
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Amino Acid Sequence
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Bacteriophage T4 / chemistry
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DNA / metabolism
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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-Binding Proteins / chemistry
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DNA-Binding Proteins / metabolism*
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Escherichia coli / enzymology
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Models, Molecular
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Molecular Sequence Data
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Nuclear Proteins / chemistry
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Nucleic Acid Conformation
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Proliferating Cell Nuclear Antigen
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Protein Structure, Tertiary
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Sequence Alignment
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Sequence Homology, Amino Acid
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Viral Proteins / chemistry
Substances
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DNA-Binding Proteins
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Nuclear Proteins
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Proliferating Cell Nuclear Antigen
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Viral Proteins
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DNA
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DNA Polymerase III
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Adenosine Triphosphatases