Goldstein J, Lehnhardt S, Inouye M
Department of Biochemistry, Robert Wood Johnson Medical School at Rutgers, University of Medicine and Dentistry of New Jersey, Piscataway 08854-5635.
J Bacteriol. 1990 Mar;172(3):1225-31. doi: 10.1128/jb.172.3.1225-1231.1990.
The hydrophobic region of the signal peptide of the OmpA protein of the Escherichia coli outer membrane was extensively altered in its hydrophobicity and predicted secondary structure by site-specific mutagenesis. The mutated signal peptides were fused to nuclease A from Staphylococcus aureus, and the function of the signal peptide was examined by measuring the rate of processing of the signal peptide. Six of the 12 mutated signal peptides in the nuclease hybrid were processed faster than the wild-type. In particular, the processing of the mutated signal peptide in which the alanine residue at position 9 was substituted with a valine residue was enhanced almost twofold over the processing of the wild-type signal peptide. In addition, the production of nuclease A fused with this mutated signal peptide also increased twofold. However, these effects were not observed when the mutated signal peptide was fused to TEM beta-lactamase. Analysis of the present mutations suggests that both overall hydrophobicity and distinct structural requirements in the hydrophobic region have important roles in signal peptide function.
通过定点诱变，大肠杆菌外膜OmpA蛋白信号肽的疏水区域在疏水性和预测的二级结构方面发生了广泛改变。将突变的信号肽与金黄色葡萄球菌的核酸酶A融合，并通过测量信号肽的加工速率来检测信号肽的功能。核酸酶杂交体中12个突变信号肽中的6个比野生型加工得更快。特别是，第9位丙氨酸残基被缬氨酸残基取代的突变信号肽的加工比野生型信号肽的加工增强了近两倍。此外，与这种突变信号肽融合的核酸酶A的产量也增加了两倍。然而，当突变信号肽与TEMβ-内酰胺酶融合时，未观察到这些效应。对当前突变的分析表明，疏水区域的整体疏水性和独特的结构要求在信号肽功能中都起着重要作用。
