1e3h
From Proteopedia
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| , resolution 2.60Å | |||||||
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| Ligands: | , | ||||||
| Gene: | GPSI (Streptomyces antibioticus) | ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
SEMET DERIVATIVE OF STREPTOMYCES ANTIBIOTICUS PNPASE/GPSI ENZYME
Overview
BACKGROUND: Polynucleotide phosphorylase (PNPase) is a polyribonucleotide nucleotidyl transferase (E.C.2.7.7.8) that degrades mRNA in prokaryotes. Streptomyces antibioticus PNPase also assays as a guanosine 3'-diphosphate 5'-triphosphate (pppGpp) synthetase (E.C.2.7.6.5). It may function to coordinate changes in mRNA lifetimes with pppGpp levels during the Streptomyces lifecycle. RESULTS: The structure of S. antibioticus PNPase without bound RNA but with the phosphate analog tungstate bound at the PNPase catalytic sites was determined by X-ray crystallography and shows a trimeric multidomain protein with a central channel. The structural core has a novel duplicated architecture formed by association of two homologous domains. The tungstate derivative structure reveals the PNPase active site in the second of these core domains. Structure-based sequence analysis suggests that the pppGpp synthetase active site is located in the first core domain. CONCLUSIONS: This is the first structure of a PNPase and shows the structural basis for the trimer assembly, the arrangement of accessory RNA binding domains, and the likely catalytic residues of the PNPase active site. A possible function of the trimer channel is as a contribution to both the processivity of degradation and the regulation of PNPase action by RNA structural elements.
About this Structure
1E3H is a Single protein structure of sequence from Streptomyces antibioticus. Full crystallographic information is available from OCA.
Reference
A duplicated fold is the structural basis for polynucleotide phosphorylase catalytic activity, processivity, and regulation., Symmons MF, Jones GH, Luisi BF, Structure. 2000 Nov 15;8(11):1215-26. PMID:11080643
Page seeded by OCA on Sun Mar 30 19:54:17 2008
