Polynucleotide phosphorylase

protein
Name = Polynucleotide Phosphorylase
caption = Structure of the PNPase trimer


width = 220
HGNCid = 23166
Symbol = PNPASE
AltSymbols = PNPase, OLD35, old-35
EntrezGene = 87178
OMIM = 610316
RefSeq = NM_033109
UniProt = Q8TCS8
PDB = 1E3P
ECnumber = 2.7.7.8
Chromosome = 2
Arm = p
Band = 15
LocusSupplementaryData =

Polynucleotide Phosphorylase (PNPase) is bifunctional enzyme with a phosphorolytic 3' to 5' exoribonuclease activity and a 3'-terminal oligonucleotide polymerase activity.cite journal
author = Yehudai-Resheff S, Hirsh M, Schuster G
title = Polynucleotide phosphorylase functions as both an exonuclease and a poly(A) polymerase in spinach chloroplasts
journal = Mol. Cell. Biol.
volume = 21 | issue = 16 | pages = 5408–16 | year = 2001
pmid = 11463823
doi = 10.1128/MCB.21.16.5408-5416.2001
issn = ] It is involved with mRNA processing and degradation in bacteria, plants,cite journal
author = Yehudai-Resheff S, Zimmer SL, Komine Y, Stern DB
title = Integration of chloroplast nucleic acid metabolism into the phosphate deprivation response in Chlamydomonas reinhardtii
journal = Plant Cell
volume = 19
issue = 3
pages = 1023–38
year = 2007
pmid = 17351118
doi = 10.1105/tpc.106.045427
issn = ] and in humans.cite journal |author=Sarkar D, Fisher PB|title=Human polynucleotide phosphorylase (hPNPase old-35): an RNA degradation enzyme with pleiotrophic biological effects
journal= Cell Cycle
volume= 5
issue= 10
pages= 1080–4
year= 2006
doi =
url = http://www.landesbioscience.com/journals/cc/article/sarkarCC5-10.pdf
pmid= 16687933]

In humans, the enzyme is encoded by the gene|PNPT1 gene. In its active form, the protein forms a ring structure consisting of three PNPase molecules. Each PNPase molecule consists of two RNase PH domains, an S1 RNA binding domain and an K-homology domain. The protein is present in bacteria and in the chloroplasts and mitochondriacite journal
author = Schilders G, van Dijk E, Raijmakers R, Pruijn GJ
title = Cell and molecular biology of the exosome: how to make or break an RNA
journal = Int. Rev. Cytol.
volume = 251
issue =
pages = 159–208
year = 2006
pmid = 16939780
doi = 10.1016/S0074-7696(06)51005-8
issn = ] of some eukaryotic cells. In eukaryotes and archaebacteria, a structurally and evolutionary related complex exists, called the "exosome" .

Confusingly, the same abbreviation ("PNPase"), is also used for another, otherwise unrelated, enzyme, namely Purine nucleoside phosphorylase.

References

External links

*
* [http://www.rcsb.org/pdb/explore.do?structureId=1E3P Crystal structure of "Streptomyces antibioticus" PNPase at the RCSB Protein Data Bank]