Further genetic analysis of the activation function of the TyrR regulatory protein of Escherichia coli
Further genetic analysis of the activation function of the TyrR regulatory protein of Escherichia coli
复制标题
大肠杆菌TyrR调节蛋白激活功能的进一步遗传分析
作者：
Ji Yang;H. Camakaris;A. Pittard
以前的报告（J. Cui和R. L.萨默维尔，细菌学杂志。175：1777-1784，1993; J. Yang，H. Camakaris和A. J. Pittard，J. Bacteriol. 175：6372-6375，1993）已经鉴定了TyrR蛋白的N-末端结构域中的许多氨基酸，这些氨基酸对于基因表达的活化是关键的，但在TyrR介导的阻遏中不起作用。这些氨基酸聚集在涉及位置2、3、5、7、9、10和16的单个区域中。使用随机和定点诱变，我们已经确定了另外8个关键氨基酸，其取代导致激活功能的显著或完全丧失。所有这些都位于TyrR的N-末端结构域。在这八个新位置和先前鉴定的未获得丙氨酸取代的位置中的五个位置处的丙氨酸扫描已经鉴定了三个氨基酸，其侧链对于活化是关键的，即D-9、R-10和D-103。位置37处的甘氨酸也是至关重要的。在其他四个位置（C-7、E-16、D-19和V-93）的丙氨酸取代引起部分但显著的活化损失，表明这些氨基酸的侧链也在活化过程中起作用。
Previous reports (J. Cui and R. L. Somerville, J. Bacteriol. 175:1777-1784, 1993; J. Yang, H. Camakaris, and A. J. Pittard, J. Bacteriol. 175:6372-6375, 1993) have identified a number of amino acids in the N-terminal domain of the TyrR protein which are critical for activation of gene expression but which play no role in TyrR-mediated repression. These amino acids were clustered in a single region involving positions 2, 3, 5, 7, 9, 10, and 16. Using random and site-directed mutagenesis, we have identified an additional eight key amino acids whose substitution results in significant or total loss of activator function. All of these are located in the N-terminal domain of TyrR. Alanine scanning at these eight new positions and at five of the previously identified positions for which alanine substitutions had not been obtained has identified three amino acids whose side chains are critical for activation, namely, D-9, R-10, and D-103. Glycine at position 37 is also of critical importance. Alanine substitutions at four other positions (C-7, E-16, D-19, and V-93) caused partial but significant loss of activation, indicating that the side chains of these amino acids also play a contributing role in the activation process.
大肠杆菌的 TyrR 蛋白，通过结构域结构的有限蛋白水解和配体介导的构象变化进行分析。
DOI：
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发表时间：
1993
期刊：
The Journal of biological chemistry
影响因子：
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作者：
Cui,J;Somerville,RL
通讯作者：
Somerville,RL