One gene, two proteins: coordinated production of a copper chaperone by differential transcript formation and translational frameshifting in Escherichia coli
One gene, two proteins: coordinated production of a copper chaperone by differential transcript formation and translational frameshifting in Escherichia coli
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DOI：
10.1111/mmi.13841
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发表时间：
2017-11-01
影响因子：
3.6
通讯作者：
Luebben, Mathias
中科院分区：
文献类型：
--
作者：
Drees, Steffen L.;Klinkert, Birgit;Luebben, Mathias
程序性核糖体移码（PRF）是一种翻译异常，导致核糖体转移到另一个阅读框架中。 PRF 在病毒基因组中很常见，使用单个核苷酸序列编码重叠框架中的两种蛋白质。在细菌和真核生物中，PRF 不太常见。我们报告了大肠杆菌铜解毒系统中的 PRF，其中由 copA 基因的前 69 个氨基酸和 C 末端框架外甘氨酸生成金属伴侣。 copA 还编码 P-1B-ATPase CopA，这是一种膜整合蛋白，也是伴侣蛋白的主要相互作用靶标。为了增强移码产生的胞质铜结合蛋白的产生，从单顺反子 copA 基因产生截短的转录物。这种较短的转录本对于产生足够量的伴侣以支持膜泵至关重要。这些发现弥补了我们对大肠杆菌细胞质铜转运的分子生理学理解的空白，揭示了 P-1B-ATPase 铜泵的全部功能需要一个类似伴侣的实体。此外，我们证明对铜的初级转录反应导致小转录物的形成，同时金属伴侣在抵抗铜冲击方面发挥着关键作用。
Programmed ribosomal frameshifting (PRF) is a translational anomaly causing the ribosome to shift into an alternative reading frame. PRFs are common in viral genomes, using a single nucleotide sequence to code for two proteins in overlapping frames. In bacteria and eukaryota, PRFs are less frequent. We report on a PRF in the copper detoxification system of Escherichia coli where a metallochaperone is generated out of the first 69 amino acids and a Cterminal out-of-frame glycine of the gene copA. copA besides codes for the P-1B-ATPase CopA, a membrane-integral protein and principal interaction target of the chaperone. To enhance the production of the frameshift-generated cytosolic copper binding protein a truncated transcript is produced from the monocistronic copA gene. This shorter transcript is essential for producing sufficient amounts of the chaperone to support the membrane pump. The findings close the gap in our understanding of the molecular physiology of cytoplasmic copper transport in E. coli, revealing that a chaperone-like entity is required for full functionality of the P-1B-ATPase copper pump. We, moreover, demonstrate that the primary transcriptional response to copper results in formation of the small transcript and concurrently, the metallochaperone plays a key role in resistance against copper shock.