4ba1 | pdb_00004ba1

Archaeal exosome (Rrp4-Rrp41(D182A)-Rrp42) bound to inorganic phosphate

spinqualitylabelsall models 4ba1, resolution 1.80Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4ba1 is a 3 chain structure with sequence from Atcc 35091. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: 1PE, NA, PEG, PO4 Related: 2br2, 2c37, 2c38, 2c39, 2je6, 2jea, 2jeb, 4ba2 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [ECX2_SULSO] Probably involved in the 3'->5' degradation of a variety of RNA species (Potential). [ECR1_SULSO] Probably involved in degradation of a variety of RNA species; could act a RNA-binding component of the exosome (Potential). [ECX1_SULSO] Probably involved in the 3'->5' degradation of a variety of RNA species (Potential). Publication Abstract from PubMed The RNA exosome is an important protein complex that functions in the 3' processing and degradation of RNA in archaeal and eukaryotic organisms. The archaeal exosome is functionally similar to bacterial polynucleotide phosphorylase (PNPase) and RNase PH enzymes as it uses inorganic phosphate (Pi) to processively cleave RNA substrates releasing nucleoside diphosphates. To shed light on the mechanism of catalysis, we have determined the crystal structures of mutant archaeal exosome in complex with either Pi or with both RNA and Pi at resolutions of 1.8 A and 2.5 A, respectively. These structures represent views of precatalytic states of the enzyme and allow the accurate determination of the substrate binding geometries. In the structure with both Pi and RNA bound, the Pi closely approaches the phosphate of the 3'-end nucleotide of the RNA and is in a perfect position to perform a nucleophilic attack. The presence of negative charge resulting from the close contacts between the phosphates appears to be neutralized by conserved positively charged residues in the active site of the archaeal exosome. The high degree of structural conservation between the archaeal exosome and the PNPase including the requirement for divalent metal ions for catalysis is discussed. Crystal structure of a 9-subunit archaeal exosome in pre-catalytic States of the phosphorolytic reaction.,Lorentzen E, Conti E Archaea. 2012;2012:721869. doi: 10.1155/2012/721869. Epub 2012 Dec 20. PMID:23319881 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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