Translation of the adhE transcript to produce ethanol dehydrogenase requires RNase III cleavage in Escherichia coli
Translation of the adhE transcript to produce ethanol dehydrogenase requires RNase III cleavage in Escherichia coli
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DOI：
10.1128/jb.178.14.4327-4332.1996
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发表时间：
1996-07-01
影响因子：
3.2
通讯作者：
Lin, ECC
中科院分区：
文献类型：
--
作者：
Aristarkhov, A;Mikulskis, A;Lin, ECC
先前的研究表明，adhe基因编码一种具有乙醇脱氢酶活性的多功能蛋白，处于转录调控之下。发酵培养的细胞的脱氢酶活性水平比有氧培养的细胞高约10倍。在这些研究中，我们将启动子定位在ADE蛋白编码区的上游。出乎意料的是，在缺乏内切核糖核酸酶III的突变体中，在添加葡萄糖的富Luria-Bertani培养基上厌氧生长的细胞中没有检测到显著的乙醇脱氢酶活性，尽管Adhe mRNA水平很高。的确，像Delta adhe突变体一样，缺乏RNaseIII的菌株不能在葡萄糖上发酵生长，而是在氧化程度更高的碳源葡萄糖醛酸上生长，计算机生成的ADHE mRNA 5‘非翻译区的二级结构表明，核糖体结合部位被分子内碱基配对阻断，似乎RNaseIII切割这个二级结构对于有效的翻译启动是必要的。
Previous studies have shown that the adhE gene, which encodes a multifunctional protein with ethanol dehydrogenase activity, is under transcriptional regulation. The level of dehydrogenase activity in cells grown fermentatively is about 10-fold higher than that in cells grown aerobically. In these studies, we mapped the promoter to a region well upstream of the protein-coding region of adhE. Unexpectedly, in mutants lacking the endoribonuclease]RNase III, no significant ethanol dehydrogenase activity was detected in cells grown anaerobically on rich (Luria-Bertani) medium supplemented with glucose, even though adhE mRNA levels were high. Indeed, like Delta adhE mutants, strains lacking RNase III failed to grow fermentatively on glucose but grew on the more oxidized carbon source glucuronate, Computer-generated secondary structures of the putative 5' untranslated region of adhE mRNA suggest that the ribosome binding site is occluded by intramolecular base pairing, It seems likely that cleavage of this secondary structure by RNase III is necessary for efficient translation initiation.