Débarbouillé M, Martin-Verstraete I, Klier A, Rapoport G
Unité de Biochimie Microbienne, URA 1300 du Centre National de la Recherche Scientifique, Paris, France.
Proc Natl Acad Sci U S A. 1991 Mar 15;88(6):2212-6. doi: 10.1073/pnas.88.6.2212.
The regulatory gene levR of the levanase operon of Bacillus subtilis was cloned and sequenced. It encodes a polypeptide of Mr 106,064 with two domains homologous to members of two families of bacterial activators. One domain in LevR is homologous with one region of bacterial regulators including SacT and SacY of B. subtilis and BglG from Escherichia coli. Another domain of LevR is homologous to one part of the central domain of NifA and NtrC, which control nitrogen assimilation in Gram-negative bacteria. The levanase promoter contains two regions almost identical to the -12, -24 consensus regions present in sigma 54-dependent promoters. The expression of the levanase operon in E. coli was strongly dependent on sigma 54. Taken together, these results suggest that the operon is expressed from a -12, -24 promoter regulated by a sigma 54-like-dependent system in B. subtilis.
克隆并测序了枯草芽孢杆菌果聚糖酶操纵子的调控基因levR。它编码一种分子量为106,064的多肽，该多肽具有两个与两类细菌激活剂家族成员同源的结构域。LevR中的一个结构域与包括枯草芽孢杆菌的SacT和SacY以及大肠杆菌的BglG在内的细菌调节因子的一个区域同源。LevR的另一个结构域与控制革兰氏阴性菌氮同化的NifA和NtrC中央结构域的一部分同源。果聚糖酶启动子包含两个区域，它们几乎与依赖于σ54的启动子中存在的-12、-24共有区域相同。果聚糖酶操纵子在大肠杆菌中的表达强烈依赖于σ54。综上所述，这些结果表明该操纵子在枯草芽孢杆菌中由一个类似σ54依赖系统调控的-12、-24启动子表达。
