3lgb
From Proteopedia
Crystal Structure of the Fe-S Domain of the yeast DNA primase
Structural highlights
Function[PRI2_YEAST] DNA primase is the polymerase that synthesizes small RNA primers for the Okazaki fragments made during discontinuous DNA replication. In a complex with DNA polymerase alpha (DNA polymerase alpha:primase) constitutes a replicative polymerase. Both primase components participate in formation of the active center, but the ATP-binding site is exclusively located on p48. Evolutionary ConservationCheck, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedBACKGROUND: DNA synthesis during replication relies on RNA primers synthesised by the primase, a specialised DNA-dependent RNA polymerase that can initiate nucleic acid synthesis de novo. In archaeal and eukaryotic organisms, the primase is a heterodimeric enzyme resulting from the constitutive association of a small (PriS) and large (PriL) subunit. The ability of the primase to initiate synthesis of an RNA primer depends on a conserved Fe-S domain at the C-terminus of PriL (PriL-CTD). However, the critical role of the PriL-CTD in the catalytic mechanism of initiation is not understood. METHODOLOGY/PRINCIPAL FINDINGS: Here we report the crystal structure of the yeast PriL-CTD at 1.55 A resolution. The structure reveals that the PriL-CTD folds in two largely independent alpha-helical domains joined at their interface by a [4Fe-4S] cluster. The larger N-terminal domain represents the most conserved portion of the PriL-CTD, whereas the smaller C-terminal domain is largely absent in archaeal PriL. Unexpectedly, the N-terminal domain reveals a striking structural similarity with the active site region of the DNA photolyase/cryptochrome family of flavoproteins. The region of similarity includes PriL-CTD residues that are known to be essential for initiation of RNA primer synthesis by the primase. CONCLUSION/SIGNIFICANCE: Our study reports the first crystallographic model of the conserved Fe-S domain of the archaeal/eukaryotic primase. The structural comparison with a cryptochrome protein bound to flavin adenine dinucleotide and single-stranded DNA provides important insight into the mechanism of RNA primer synthesis by the primase. Shared active site architecture between the large subunit of eukaryotic primase and DNA photolyase.,Sauguet L, Klinge S, Perera RL, Maman JD, Pellegrini L PLoS One. 2010 Apr 9;5(4):e10083. PMID:20404922[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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