کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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2181390 | 1095293 | 2008 | 12 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: A cyanase is transcriptionally regulated by arginine and involved in cyanate decomposition in Sordaria macrospora A cyanase is transcriptionally regulated by arginine and involved in cyanate decomposition in Sordaria macrospora](/preview/png/2181390.png)
Cyanase degrades toxic cyanate to NH3 and CO2 in a bicarbonate-dependent reaction. High concentrations of cyanate are fairly toxic to organisms. Here, we characterize a eukaryotic cyanase for the first time. We have isolated the cyn1 gene encoding a cyanase from the filamentous ascomycete Sordaria macrospora and functionally characterized the cyn1 product after heterologous expression in Escherichia coli. Site-directed mutagenesis confirmed a predicted catalytic centre of three conserved amino-acids. A Δcyn1 knockout in S. macrospora was totally devoid of cyanase activity and showed an increased sensitivity to exogenously supplied cyanate in an arginine-depleted medium, defects in ascospore germination, but no other obvious morphological phenotype. By means of real-time PCR we have demonstrated that the transcriptional level of cyn1 is markedly elevated in the presence of cyanate and down-regulated by addition of arginine. The putative functions of cyanase in fungi are discussed.
Journal: Fungal Genetics and Biology - Volume 45, Issue 11, November 2008, Pages 1458–1469