Sabathé Fabrice, Croux Christian, Cornillot Emmanuel, Soucaille Philippe
Centre de Bioingénierie Gilbert Durand, UMR-CNRS 5504, Lab. Ass. INRA, Institut National des Sciences Appliquées, 135 avenue de Rangueil, 31077 Toulouse, France.
FEMS Microbiol Lett. 2002 Apr 23;210(1):93-8. doi: 10.1111/j.1574-6968.2002.tb11165.x.
Clostridium acetobutylicum produces an extracellular alpha-amylase when grown on glucose as the sole carbon source. This enzyme was previously characterized from a biochemical point of view but its encoding gene was never identified. The 2283-bp amyP gene encodes a 83013-Da mature protein with an N-terminal domain that exhibits strong identity to the family 13 glycosyl hydrolases such as the Bacillus alpha-amylases. Transcriptional analysis revealed that amyP is transcribed in solventogenic but not in acidogenic chemostat cultures. These results are in agreement with the extracellular alpha-amylase activities indicating that the expression of amyP is regulated at the transcriptional level. amyP is located on the pSOL1 megaplasmid that carries all the genes involved in the final steps of solvent formation. Degeneration of C. acetobutylicum has been associated to the loss of pSOL1. We demonstrate here that amyP can be used as a reporter system to quantitatively follow this phenomenon.
丙酮丁醇梭菌以葡萄糖作为唯一碳源生长时会产生一种细胞外α-淀粉酶。该酶先前已从生化角度进行了表征，但其编码基因从未被鉴定。2283 bp的amyP基因编码一个83013 Da的成熟蛋白，该蛋白的N端结构域与第13家族糖基水解酶（如芽孢杆菌α-淀粉酶）具有高度同源性。转录分析表明，amyP在溶剂生成期的恒化器培养物中表达，而在产酸期的恒化器培养物中不表达。这些结果与细胞外α-淀粉酶活性一致，表明amyP的表达在转录水平上受到调控。amyP位于携带所有参与溶剂形成最后步骤基因的pSOL1大质粒上。丙酮丁醇梭菌的退化与pSOL1的丢失有关。我们在此证明，amyP可作为一种报告系统来定量跟踪这一现象。
