Abstract
We have solved the crystal structures of the bacteriophage RB69 sliding clamp, its complex with a peptide essential for DNA polymerase interactions, and the DNA polymerase complexed with primer-template DNA. The editing complex structure shows a partially melted duplex DNA exiting from the exonuclease domain at an unexpected angle and significant changes in the protein structure. The clamp complex shows the C-terminal 11 residues of polymerase bound in a hydrophobic pocket, and it allows docking of the editing and clamp structures together. The peptide binds to the sliding clamp at a position identical to that of a replication inhibitor peptide bound to PCNA, suggesting that the replication inhibitor protein p21CIP1 functions by competing with eukaryotic polymerases for the same binding pocket on the clamp.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Amino Acid Sequence
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Bacteriophages / genetics
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Binding Sites
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Crystallography, X-Ray
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Cyclin-Dependent Kinase Inhibitor p21
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Cyclins / metabolism
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DNA Replication*
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DNA, Viral / chemistry*
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DNA, Viral / metabolism*
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DNA-Directed DNA Polymerase / chemistry*
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DNA-Directed DNA Polymerase / metabolism*
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Models, Molecular
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Molecular Sequence Data
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Nucleic Acid Conformation
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Nucleic Acid Denaturation
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Proliferating Cell Nuclear Antigen / chemistry
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Proliferating Cell Nuclear Antigen / metabolism
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Protein Conformation
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Protein Structure, Secondary
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Templates, Genetic*
Substances
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Cyclin-Dependent Kinase Inhibitor p21
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Cyclins
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DNA, Viral
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Proliferating Cell Nuclear Antigen
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DNA-Directed DNA Polymerase
Associated data
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PDB/1B77
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PDB/1B8H
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PDB/1CLQ
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PDB/1QE4