View source for 1non


==PyrR, the regulator of the pyrimidine biosynthetic operon in Bacillus caldolyticus==
<StructureSection load='1non' size='340' side='right'caption='[[1non]], [[Resolution|resolution]] 2.40&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1non]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Bacillus_caldolyticus Bacillus caldolyticus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1NON OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1NON FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.4&#8491;</td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1non FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1non OCA], [https://pdbe.org/1non PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1non RCSB], [https://www.ebi.ac.uk/pdbsum/1non PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1non ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/PYRR_BACCL PYRR_BACCL] Regulates transcriptional attenuation of the pyrimidine nucleotide (pyr) operon by binding in a uridine-dependent manner to specific sites on pyr mRNA. This disrupts an antiterminator hairpin in the RNA and favors formation of a downstream transcription terminator, leading to a reduced expression of downstream genes (Probable).  Also displays a weak uracil phosphoribosyltransferase activity which is not physiologically significant.
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/no/1non_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1non ConSurf].
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== Publication Abstract from PubMed ==
PyrR is a protein that regulates the expression of genes and operons of pyrimidine nucleotide biosynthesis (pyr genes) in many bacteria. PyrR acts by binding to specific sequences on pyr mRNA and causing transcriptional attenuation when intracellular levels of uridine nucleotides are elevated. PyrR from Bacillus subtilis has been purified and extensively studied. In this work, we describe the purification to homogeneity and characterization of recombinant PyrR from the thermophile Bacillus caldolyticus and the crystal structures of unliganded PyrR and a PyrR-nucleotide complex. The B. caldolyticus pyrR gene was previously shown to restore normal regulation of the B. subtilis pyr operon in a pyrR deletion mutant. Like B. subtilis PyrR, B. caldolyticus PyrR catalyzes the uracil phosphoribosyltransferase reaction but with maximal activity at 60 degrees C. Crystal structures of B. caldolyticus PyrR reveal a dimer similar to the B. subtilis PyrR dimer and, for the first time, binding sites for nucleotides. UMP and GMP, accompanied by Mg2+, bind specifically to PyrR active sites. Nucleotide binding to PyrR is similar to other phosphoribosyltransferases, but Mg2+ binding differs. GMP binding was unexpected. The protein bound specific sequences of pyr RNA 100 to 1,000 times more tightly than B. subtilis PyrR, depending on the RNA tested and the assay method; uridine nucleotides enhanced RNA binding, but guanosine nucleotides antagonized it. The new findings of specific GMP binding and its antagonism of RNA binding suggest cross-regulation of the pyr operon by purines.

Structure of the nucleotide complex of PyrR, the pyr attenuation protein from Bacillus caldolyticus, suggests dual regulation by pyrimidine and purine nucleotides.,Chander P, Halbig KM, Miller JK, Fields CJ, Bonner HK, Grabner GK, Switzer RL, Smith JL J Bacteriol. 2005 Mar;187(5):1773-82. PMID:15716449<ref>PMID:15716449</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Bonner HK]]
[[Category: Chander P]]
[[Category: Grabner GK]]
[[Category: Halbig KM]]
[[Category: Miller JK]]
[[Category: Smith JL]]
[[Category: Switzer RL]]