scholarly journals Differences in the Roles of a Glutamine Amidotransferase Subunit of Pyridoxal 5'-Phosphate Synthase betweenBacillus circulansandBacillus subtilis

2013 ◽  
Vol 77 (7) ◽  
pp. 1481-1485
Author(s):  
Shiori ITAGAKI ◽  
Minami HAGA ◽  
Yuji OIKAWA ◽  
Ayaka SAKODA ◽  
Yoshie OHKE ◽  
...  
Keyword(s):  
Glutamine Amidotransferase ◽  
Phosphate Synthase

Catalytic Mechanism of 3-Deoxy-D-manno-2-octulosonate-8-phosphate Synthase

2001 ◽  
Vol 5 (2) ◽  
pp. 127-138 ◽  
Author(s):  
Timor Baasov ◽  
Rachel Tkacz ◽  
Shani Sheffer-Dee-Noor ◽  
Valery Belakhov
Keyword(s):  
Catalytic Mechanism ◽  
Phosphate Synthase

scholarly journals Structural requirements of the glucocorticoid-response unit of the carbamoyl-phosphate synthase gene

2004 ◽  
Vol 382 (2) ◽  
pp. 463-470 ◽  
Author(s):  
Onard J. L. M. SCHONEVELD ◽  
Ingrid C. GAEMERS ◽  
Atze T. DAS ◽  
Maarten HOOGENKAMP ◽  
Johan RENES ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Distal Enhancer ◽  
Carbamoyl Phosphate ◽  
Gene Encoding ◽  
Response Elements ◽  
Response Unit ◽  
Glucocorticoid Response ◽  
Protein Functions ◽  
Spatial Positioning ◽  
Phosphate Synthase

The GRU (glucocorticoid-response unit) within the distal enhancer of the gene encoding carbamoyl-phosphate synthase, which comprises REs (response elements) for the GR (glucocorticoid receptor) and the liver-enriched transcription factors FoxA (forkhead box A) and C/EBP (CCAAT/enhancer-binding protein), and a binding site for an unknown protein denoted P3, is one of the simplest GRUs described. In this study, we have established that the activity of this GRU depends strongly on the positioning and spacing of its REs. Mutation of the P3 site within the 25 bp FoxA–GR spacer eliminated GRU activity, but the requirement for P3 could be overcome by decreasing the length of this spacer to ≤12 bp, by optimizing the sequence of the REs in the GRU, and by replacing the P3 sequence with a C/EBPβ sequence. With spacers of ≤12 bp, the activity of the GRU depended on the helical orientation of the FoxA and GR REs, with highest activities observed at 2 and 12 bp respectively. Elimination of the 6 bp C/EBP–FoxA spacer also increased GRU activity 2-fold. Together, these results indicate that the spatial positioning of the transcription factors that bind to the GRU determines its activity and that the P3 complex, which binds to the DNA via a 75 kDa protein, functions to facilitate interaction between the FoxA and glucocorticoid response elements when the distance between these transcription factors means that they have difficulties contacting each other.

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