Effects of the complete removal of basic amino acid residues from the signal peptide on secretion of lipoprotein in Escherichia coli.
Effects of the complete removal of basic amino acid residues from the signal peptide on secretion of lipoprotein in Escherichia coli.
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DOI：
10.1016/s0021-9258(18)32343-3
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发表时间：
1983-06
期刊：
影响因子：
--
通讯作者：
G. Vlasuk;S. Inouye;H. Ito;K. Itakura;M. Inouye
中科院分区：
文献类型：
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作者：
G. Vlasuk;S. Inouye;H. Ito;K. Itakura;M. Inouye
我们研究了主要外膜脂蛋白前体前脂蛋白带正电荷的 NH2 末端在大肠杆菌分泌的早期步骤中的重要性。为此，我们使用寡核苷酸定向诱变产生了三个突变体，其中 NH2 末端区域的电荷从 +2 变为 +1、0 和 -2。结果表明，带正电荷的 NH2 末端的存在促进了前脂蛋白的合成。此外，脂蛋白前体穿过细胞质膜的易位绝对不需要其NH2末端有任何碱性氨基酸。然而，带净负电荷的 NH2 末端的存在导致脂蛋白原在细胞质中初始积累，该蛋白在翻译后缓慢地跨细胞质膜易位，其速率取决于该区域中存在的正电荷数量。对这些突变体的分析清楚地证明了脂蛋白信号肽的 NH2 末端在大肠杆菌中启动该蛋白的分泌中的重要性。
We have examined the importance of the positively charged NH2 terminus of the major outer membrane lipoprotein precursor, prolipoprotein, in the early steps of secretion in Escherichia coli. For this purpose, we have generated three mutants using oligonucleotide-directed mutagenesis in which the charge at the NH2-terminal region was changed from +2 to +1, 0, and -2. The results indicate that the synthesis of prolipoprotein is facilitated by the presence of a positively charged NH2 terminus. In addition, the translocation of prolipoprotein across the cytoplasmic membrane does not absolutely require any basic amino acids at its NH2 terminus. However, the presence of a net negatively charged NH2 terminus causes an initial cytoplasmic accumulation of prolipoprotein which is slowly, post-translationally translocated across the cytoplasmic membrane at a rate which is dependent on the number of positive charges present in this region. The analysis of these mutants clearly demonstrates the importance of the NH2 terminus of the lipoprotein signal peptide in initiating the secretion of this protein in E. coli.