3q36

Crystal structure of the 4Fe-4S cluster domain of human DNA primase large subunit

spinqualitylabelsall models 3q36, resolution 2.50Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3q36 is a 2 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.5Å Ligands: FE Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function PRI2_HUMAN DNA primase is the polymerase that synthesizes small RNA primers for the Okazaki fragments made during discontinuous DNA replication. Publication Abstract from PubMed DNA polymerases cannot synthesize DNA without a primer, and DNA primase is the only specialized enzyme capable of de novo synthesis of short RNA primers. In eukaryotes, primase functions within a heterotetrameric complex in concert with a tightly bound DNA polymerase alpha (Pol alpha). In humans, the Pol alpha part is comprised of a catalytic subunit (p180) and an accessory subunit B (p70), and the primase part consists of a small catalytic subunit (p49) and a large essential subunit (p58). The latter subunit participates in primer synthesis, counts the number of nucleotides in a primer, assists the release of the primer-template from primase and transfers it to the Pol alpha active site. Recently reported crystal structures of the C-terminal domains of the yeast and human enzymes' large subunits provided critical information related to their structure, possible sites for binding of nucleotides and template DNA, as well as the overall organization of eukaryotic primases. However, the structures also revealed a difference in the folding of their proposed DNA-binding fragments, raising the possibility that yeast and human proteins are functionally different. Here we report new structure of the C-terminal domain of the human primase p58 subunit. This structure exhibits a fold similar to a fold reported for the yeast protein but different than a fold reported for the human protein. Based on a comparative analysis of all three C-terminal domain structures, we propose a mechanism of RNA primer length counting and dissociation of the primer-template from primase by a switch in conformation of the ssDNA-binding region of p58. Crystal structure of the C-terminal domain of human DNA primase large subunit: Implications for the mechanism of the primase - polymerase alpha switch.,Agarkar VB, Babayeva ND, Pavlov YI, Tahirov TH Cell Cycle. 2011 Mar 15;10(6). PMID:21346410 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also RNA polymerase 3D structures

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