Two proteins, YfiA and YhbH, associated with resting ribosomes in stationary phase Escherichia coli
Two proteins, YfiA and YhbH, associated with resting ribosomes in stationary phase Escherichia coli
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DOI：
10.1046/j.1365-2443.2000.00389.x
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发表时间：
2000-12-01
期刊：
影响因子：
2.1
通讯作者：
Wada, A
中科院分区：
文献类型：
--
作者：
Maki, Y;Yoshida, H;Wada, A
背景：大肠杆菌中的核糖体在固定相中改变其组成和构象。已知核糖体调节因子（RMF）和核糖体蛋白S22与稳定期核糖体相关。RMF结合导致翻译活性的丧失和70S核糖体二聚化为100S核糖体，这可能增加细胞在稳定期的存活。大肠杆菌核糖体在稳定期。这些蛋白质是命名为yfiA和yhbH的ORF的产物。它们的产物蛋白质YfiA和YhbH在核糖体颗粒中的拷贝数之和在对数期较低，但在稳定期增加到接近1。YfiA被发现在70S核糖体部分，而不是100S。另一方面，YhbH被检测到专门在100 S核糖体部分。当稳定期细胞转移到新鲜培养基中时，在70 S核糖体组分中发现了YfiA和YhbH，而在多核糖体组分中没有发现。大肠杆菌核糖体被发现在稳定期积累，导致几种类型的核糖体的形成。它们不太可能在对数期细胞中翻译的延伸步骤中发挥作用，但可能参与稳定期核糖体的稳定和保存，这可能是细胞存活所必需的。
Background: Ribosomes in Escherichia coli change their composition and conformation in the stationary phase. Ribosome modulation factor (RMF) and ribosomal protein S22 are known to be associated with stationary phase ribosomes. RMF association causes the loss of translational activity and the dimerization of 70S ribosomes into 100S ribosomes, which may increase cell survival in the stationary phase.Results: Two weakly acidic proteins having related amino acid sequences were found to be associated with E. coli ribosomes in the stationary phase. These proteins are the products of ORFs named yfiA and yhbH. The sum of the copy numbers of their product proteins, YfiA and YhbH, in the ribosomal particles was low in the log phase, but increased to nearly one in the stationary phase. YfiA was found in the 70S ribosomal fraction rather than the 100S. On the other hand, YhbH was detected exclusively in the 100S ribosomal fraction. When the stationary phase cells were transferred to fresh medium, YfiA and YhbH were found in the 70S ribosomal fraction, but not in the polysome fraction.Conclusions: Two proteins, YfiA and YhbH, associated with E. coli ribosomes were found to accumulate in the stationary phase, leading to the formation of several types of ribosomes. They are not likely to have roles in the elongation step of the translation in log phase cells, but are likely to be involved in the stabilization and preservation of ribosomes in the stationary phase, which might be necessary for cell survival.