Regulatory features of the trp operon and the crystal structure of the trp RNA-binding attenuation protein from Bacillus stearothermophilus
Regulatory features of the trp operon and the crystal structure of the trp RNA-binding attenuation protein from Bacillus stearothermophilus
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DOI：
10.1006/jmbi.1999.2834
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发表时间：
1999-06-18
影响因子：
5.6
通讯作者：
Gollnick, P
中科院分区：
文献类型：
--
作者：
Chen, XP;Antson, AA;Gollnick, P
顺式和trails作用的调控元件的表征表明，嗜热脂肪芽孢杆菌trp操纵子由类似于控制枯草芽孢杆菌中的trp操纵子的衰减机制调节。二级结构预测表明，尝试mRNA的前导区能够折叠成终止子和antiterminator RNA结构。B。嗜热脂肪菌还编码与调节B减毒的RNA结合蛋白（TRAP）具有77%序列同一性的RNA结合蛋白。枯草杆菌。该蛋白质的X射线结构已在与L-色氨酸的复合物中以2.5埃分辨率测定。就像B。枯草杆菌蛋白、B.嗜热脂肪菌TRAP具有11个亚基，以环状结构排列。这两种结构中的中心空腔具有不同的尺寸和相反的电荷分布，并且在B内填充。嗜热脂肪菌TRAP晶形不产生B中所见的头对头二聚体。枯草杆菌蛋白，这表明这些属性都不是功能上重要的。然而，L-色氨酸结合的模式和所提出的RNA结合表面是相似的，这表明两种蛋白质都被L-色氨酸激活并以基本相同的方式结合RNA。正如预期的那样，来自嗜热脂肪芽孢杆菌B的TRAP：RNA复合物比来自枯草芽孢杆菌B的TRAP：RNA复合物显著更耐热，最佳结合发生在70 ℃。(C)北京：科学出版社.
Characterization of both the cis and trails-acting regulatory elements indicates that the Bacillus stearothermophilus trp operon is regulated by an attenuation mechanism similar to that which controls the trp operon in Bacillus subtilis. Secondary structure predictions indicate that the leader region of the try mRNA is capable of folding into terminator and antiterminator RNA structures. B. stearothermophilus also encodes an RNA-binding protein with 77% sequence identity with the RNA-binding protein (TRAP) that regulates attenuation in B. subtilis. The X-ray structure of this protein has been determined in complex with L-tryptophan at 2.5 Angstrom resolution. Like the B. subtilis protein, B. stearothermophilus TRAP has 11 subunits arranged in a ring-like structure. The central cavities in these two structures have different sizes and opposite charge distributions, and packing within the B. stearothermophilus TRAP crystal form does not generate the head-to-head dimers seen in the B. subtilis protein, suggesting that neither of these properties is functionally important. However, the mode of L-tryptophan binding and the proposed RNA binding surfaces are similar, indicating that both proteins are activated by L-tryptophan and bind RNA in essentially the same way. As expected, the TRAP:RNA complex from B, stearothermophilus is significantly more thermostable than that from B, subtilis, with optimal binding occurring at 70 degrees C. (C) 1999 Academic Press.