1e3p
From Proteopedia
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==Overview== | ==Overview== | ||
| - | BACKGROUND: Polynucleotide phosphorylase (PNPase) is a polyribonucleotide | + | 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== | ==About this Structure== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Streptomyces antibioticus]] | [[Category: Streptomyces antibioticus]] | ||
| - | [[Category: Jones, G | + | [[Category: Jones, G H.]] |
| - | [[Category: Luisi, B | + | [[Category: Luisi, B F.]] |
| - | [[Category: Symmons, M | + | [[Category: Symmons, M F.]] |
[[Category: SO4]] | [[Category: SO4]] | ||
[[Category: WO4]] | [[Category: WO4]] | ||
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[[Category: rna degradation]] | [[Category: rna degradation]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:23:25 2008'' |
Revision as of 10:23, 21 February 2008
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TUNGSTATE 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
1E3P is a Single protein structure of sequence from Streptomyces antibioticus with and as ligands. Known structural/functional Site: . 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 Thu Feb 21 12:23:25 2008
