Lin R, Ernsting B, Hirshfield I N, Matthews R G, Neidhardt F C, Clark R L, Newman E B
Biology Department, Concordia University, Montreal, Quebec, Canada.
J Bacteriol. 1992 May;174(9):2779-84. doi: 10.1128/jb.174.9.2779-2784.1992.
In Escherichia coli K-12, expression of the lysU gene is regulated by the lrp gene product, as indicated by an increase in the level of lysyl-tRNA synthetase activity and LysU protein in an lrp mutant. Comparison of the patterns of protein expression visualized by two-dimensional gel electrophoresis indicated that LysU is present at higher levels in an lrp strain than in its isogenic lrp+ parent. The purified lrp gene product was shown to bind to sites upstream of the lysU gene and to protect several sites against DNase I digestion. A region extending over 100 nucleotides, between 60 and 160 nucleotides upstream from the start of the lysU coding sequence, showed altered sensitivity to DNase I digestion in the presence of the Lrp protein. The extent of protected DNA suggests a complex interaction of Lrp protein and upstream lysU DNA.
在大肠杆菌K-12中，lysU基因的表达受lrp基因产物调控，这一点可通过lrp突变体中赖氨酰-tRNA合成酶活性和LysU蛋白水平的升高得以体现。二维凝胶电泳显示的蛋白质表达模式比较表明，LysU在lrp菌株中的水平高于其同基因的lrp+亲本。纯化的lrp基因产物被证明可与lysU基因上游的位点结合，并保护多个位点免受DNase I消化。在lysU编码序列起始点上游60至160个核苷酸之间，一个延伸超过100个核苷酸的区域，在Lrp蛋白存在的情况下，对DNase I消化的敏感性发生了改变。受保护的DNA范围表明Lrp蛋白与lysU基因上游DNA存在复杂的相互作用。
