A fail-safe system for the ribosome under zinc-limiting conditions in Bacillus subtilis
A fail-safe system for the ribosome under zinc-limiting conditions in Bacillus subtilis
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DOI：
10.1111/j.1365-2958.2006.05513.x
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发表时间：
2007-01-01
影响因子：
3.6
通讯作者：
Kawamura, Fujio
中科院分区：
文献类型：
--
作者：
Natori, Yousuke;Nanamiya, Hideaki;Kawamura, Fujio
由于锌是所有活细胞必需的微量金属离子，细胞制定了各种策略来科普锌饥饿。在枯草芽孢杆菌中，编码核糖体蛋白L31和S14的基因被复制成两种类型：一种类型包含锌结合基序（RpmE或RpsN），而另一种不包含锌结合基序（YtiA或YhzA）。我们以前已经表明，YtiA从已经组装的核糖体中置换RpmE（L31）是由锌控制的，这种置换可能有助于锌限制条件下的锌动员。我们在这里提出，两种类型的S14之间的转换具有不同的意义。rpsN是生长所必需的，RpsN的缺失导致缺陷的30S亚基。YhzA可以在功能上取代RpsN，以允许在锌限制条件下继续核糖体组装。与YtiA不同，YhzA以较慢的速率出现在核糖体中，这与掺入新合成的核糖体而不是预先存在的核糖体一致。这些结果提出了可能性，YhzA是参与一个故障安全系统的从头合成的核糖体在锌限制条件下。
As zinc is an essential trace metal ion for all living cells, cells elaborate a variety of strategies to cope with zinc starvation. In Bacillus subtilis, genes encoding ribosomal proteins L31 and S14 are duplicated into two types: one type contains a zinc-binding motif (RpmE or RpsN), whereas the other does not (YtiA or YhzA). We have previously shown that displacement of RpmE (L31) by YtiA from already assembled ribosomes is controlled by zinc, and this replacement could contribute to zinc mobilization under zinc-limiting conditions. We propose here that the switch between the two types of S14 has a different significance. rpsN is indispensable for growth and depletion of RpsN results in defective 30S subunits. YhzA can functionally replace RpsN to allow continued ribosome assembly under zinc-limiting conditions. Unlike YtiA, YhzA appeared in the ribosome at a slower rate consistent with incorporation into newly synthesized, rather than pre-existing ribosomes. These results raise the possibility that YhzA is involved in a fail-safe system for the de novo synthesis of ribosomes under zinc-limiting conditions.