Abstract
All cellular organisms use specialized RNA polymerases called "primases" to synthesize RNA primers for the initiation of DNA replication. The high-resolution crystal structure of a primase, comprising the catalytic core of the Escherichia coli DnaG protein, was determined. The core structure contains an active-site architecture that is unrelated to other DNA or RNA polymerase palm folds, but is instead related to the "toprim" fold. On the basis of the structure, it is likely that DnaG binds nucleic acid in a groove clustered with invariant residues and that DnaG is positioned within the replisome to accept single-stranded DNA directly from the replicative helicase.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Motifs
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Amino Acid Sequence
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Binding Sites
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Catalytic Domain
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Crystallography, X-Ray
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DNA Helicases / chemistry
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DNA Helicases / metabolism
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DNA Primase / chemistry*
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DNA Primase / metabolism*
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DNA Replication
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DNA, Bacterial / metabolism
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DNA, Single-Stranded / metabolism*
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DNA-Directed RNA Polymerases / chemistry*
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DNA-Directed RNA Polymerases / metabolism
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Escherichia coli / enzymology*
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Escherichia coli / metabolism
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Metals / metabolism
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Models, Molecular
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Molecular Sequence Data
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Nucleic Acid Hybridization
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Protein Conformation
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Protein Folding
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Protein Structure, Secondary
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Protein Structure, Tertiary
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RNA / biosynthesis
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Recombinant Proteins / chemistry
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Recombinant Proteins / metabolism
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Templates, Genetic
Substances
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DNA, Bacterial
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DNA, Single-Stranded
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Metals
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RNA primers
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Recombinant Proteins
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RNA
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DNA Primase
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DNA-Directed RNA Polymerases
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DNA Helicases