Rothstein S J, Gatenby A A, Willey D L, Gray J C
Proc Natl Acad Sci U S A. 1985 Dec;82(23):7955-9. doi: 10.1073/pnas.82.23.7955.
Various sequences from the 5' end of the pea chloroplast gene for cytochrome f have been fused in the correct reading frame with lacZ, and the cellular location of the hybrid polypeptides in Escherichia coli has been examined. Hybrid polypeptides containing N-terminal parts of cytochrome f are located in the cytoplasmic membrane of E. coli. Membrane localization is most efficient when the intact signal sequence of cytochrome f is present at the N-terminal end of the fusion proteins. Fusion within the signal sequence, so that the processing site is absent, reduces the efficiency of membrane binding. Membrane insertion of fusion proteins containing signal sequences is prevented in a temperature-sensitive secA strain at the nonpermissive temperature and the hybrid proteins accumulate in the cytoplasm. This indicates that specific recognition of the chloroplast signal sequence occurs in the bacterial secretory pathway.
已将豌豆叶绿体细胞色素f基因5'端的各种序列与lacZ以正确的阅读框融合，并检测了杂交多肽在大肠杆菌中的细胞定位。含有细胞色素f N端部分的杂交多肽位于大肠杆菌的细胞质膜中。当细胞色素f的完整信号序列存在于融合蛋白的N端时，膜定位效率最高。信号序列内的融合导致加工位点缺失，从而降低了膜结合效率。在温度敏感的secA菌株中，在非允许温度下，含有信号序列的融合蛋白的膜插入受到阻止，杂交蛋白在细胞质中积累。这表明叶绿体信号序列在细菌分泌途径中发生了特异性识别。
