1ro0
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(New page: 200px<br /><applet load="1ro0" size="450" color="white" frame="true" align="right" spinBox="true" caption="1ro0, resolution 1.8Å" /> '''Bifunctional DNA prim...)
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Revision as of 20:52, 24 November 2007
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Bifunctional DNA primase/polymerase domain of ORF904 from the archaeal plasmid pRN1- Triple mutant F50M/L107M/L110M SeMet remote
Overview
Genome replication generally requires primases, which synthesize an, initial oligonucleotide primer, and DNA polymerases, which elongate the, primer. Primase and DNA polymerase activities are combined, however, in, newly identified replicases from archaeal plasmids, such as pRN1 from, Sulfolobus islandicus. Here we present a structure-function analysis of, the pRN1 primase-polymerase (prim-pol) domain. The crystal structure shows, a central depression lined by conserved residues. Mutations on one side of, the depression reduce DNA affinity. On the opposite side of the depression, cluster three acidic residues and a histidine, which are required for, primase and DNA polymerase activity. One acidic residue binds a manganese, ion, suggestive of a metal-dependent catalytic mechanism. The structure, does not show any similarity to DNA polymerases, but is distantly related, to archaeal and eukaryotic primases, with corresponding active-site, residues. We propose that archaeal and eukaryotic primases and the, prim-pol domain have a common evolutionary ancestor, a bifunctional, replicase for small DNA genomes.
About this Structure
1RO0 is a Single protein structure of sequence from Sulfolobus islandicus with ZN as ligand. Full crystallographic information is available from OCA.
Reference
Structure of a bifunctional DNA primase-polymerase., Lipps G, Weinzierl AO, von Scheven G, Buchen C, Cramer P, Nat Struct Mol Biol. 2004 Feb;11(2):157-62. Epub 2004 Jan 18. PMID:14730355
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