Coulton J W, Reid G K, Campana A
Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada.
J Bacteriol. 1988 May;170(5):2267-75. doi: 10.1128/jb.170.5.2267-2275.1988.
The fhuA gene of Escherichia coli K-12 encodes an outer membrane protein that acts as the ferrichrome-iron(III) receptor. To determine the export signals and sorting information within FhuA, gene fusions of fhuA'-'lacZ and fhuA'-'phoA were constructed. Although a FhuA'-'LacZ hybrid protein was detected in the Triton X-100-insoluble fraction of the cell envelope, direct immunoelectron microscopic observation showed that this protein remained in the cytoplasm. FhuA'-'PhoA hybrid proteins were all exported across the cytoplasmic membrane. Those hybrids containing up to 88 amino acids of FhuA (FhuA88) fused to PhoA were released along with other periplasmic proteins. Hybrids containing 180 or more amino acids of FhuA (FhuA180) fused to PhoA were associated with the outer membrane. It is proposed that some information inherent in the sequences between FhuA88 and FhuA180 confers stable association with the outer membrane.
大肠杆菌K - 12的fhuA基因编码一种外膜蛋白，该蛋白作为高铁色素 - 铁（III）受体。为了确定FhuA内的输出信号和分选信息，构建了fhuA'-'lacZ和fhuA'-'phoA基因融合体。尽管在细胞膜的Triton X - 100不溶性部分检测到了FhuA'-'LacZ杂合蛋白，但直接免疫电子显微镜观察表明该蛋白仍留在细胞质中。FhuA'-'PhoA杂合蛋白均穿过细胞质膜输出。那些与PhoA融合的含有多达88个FhuA氨基酸（FhuA88）的杂合体与其他周质蛋白一起释放。与PhoA融合的含有180个或更多FhuA氨基酸（FhuA180）的杂合体与外膜相关。有人提出，FhuA88和FhuA180之间序列中固有的一些信息赋予了与外膜的稳定结合。
