1non
From Proteopedia
(New page: 200px<br /><applet load="1non" size="450" color="white" frame="true" align="right" spinBox="true" caption="1non, resolution 2.40Å" /> '''PyrR, the regulator ...) |
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caption="1non, resolution 2.40Å" /> | caption="1non, resolution 2.40Å" /> | ||
'''PyrR, the regulator of the pyrimidine biosynthetic operon in Bacillus caldolyticus'''<br /> | '''PyrR, the regulator of the pyrimidine biosynthetic operon in Bacillus caldolyticus'''<br /> | ||
==Overview== | ==Overview== | ||
| - | PyrR is a protein that regulates the expression of genes and operons of | + | 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. |
==About this Structure== | ==About this Structure== | ||
| - | 1NON is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_caldolyticus Bacillus caldolyticus]. Active as [http://en.wikipedia.org/wiki/Uracil_phosphoribosyltransferase Uracil phosphoribosyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.2.9 2.4.2.9] Full crystallographic information is available from [http:// | + | 1NON is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_caldolyticus Bacillus caldolyticus]. Active as [http://en.wikipedia.org/wiki/Uracil_phosphoribosyltransferase Uracil phosphoribosyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.2.9 2.4.2.9] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1NON OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Uracil phosphoribosyltransferase]] | [[Category: Uracil phosphoribosyltransferase]] | ||
| - | [[Category: Bonner, H | + | [[Category: Bonner, H K.]] |
[[Category: Chander, P.]] | [[Category: Chander, P.]] | ||
| - | [[Category: Grabner, G | + | [[Category: Grabner, G K.]] |
| - | [[Category: Halbig, K | + | [[Category: Halbig, K M.]] |
| - | [[Category: Miller, J | + | [[Category: Miller, J K.]] |
| - | [[Category: Smith, J | + | [[Category: Smith, J L.]] |
| - | [[Category: Switzer, R | + | [[Category: Switzer, R L.]] |
[[Category: transcription regulation; attenuation protein; rna-binding protein; pyrimidine biosynthesis; transferase; prtase; uracil phosphoribosyltransferase; bifunctional enzyme]] | [[Category: transcription regulation; attenuation protein; rna-binding protein; pyrimidine biosynthesis; transferase; prtase; uracil phosphoribosyltransferase; bifunctional enzyme]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:08:21 2008'' |
Revision as of 12:08, 21 February 2008
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PyrR, the regulator of the pyrimidine biosynthetic operon in Bacillus caldolyticus
Overview
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.
About this Structure
1NON is a Single protein structure of sequence from Bacillus caldolyticus. Active as Uracil phosphoribosyltransferase, with EC number 2.4.2.9 Full crystallographic information is available from OCA.
Reference
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
Page seeded by OCA on Thu Feb 21 14:08:21 2008
Categories: Bacillus caldolyticus | Single protein | Uracil phosphoribosyltransferase | Bonner, H K. | Chander, P. | Grabner, G K. | Halbig, K M. | Miller, J K. | Smith, J L. | Switzer, R L. | Transcription regulation; attenuation protein; rna-binding protein; pyrimidine biosynthesis; transferase; prtase; uracil phosphoribosyltransferase; bifunctional enzyme
