Identification of a Conserved N-Terminal Sequence Involved in Transmembrane Signal Transduction in EnvZ

To determine whether N-terminal sequences are involved in the transmembrane signaling mechanism of EnvZ, the nucleotide sequences of envZ genes from several enteric bacteria were determined. Comparative analysis revealed that the amino acid sequence between Pro41 and Glu53 was highly conserved. To further analyze the role of the conserved sequence, envZ of Escherichia coli was subjected to random PCR mutagenesis and mutant alleles that produced a high-osmolarity phenotype, in which ompF was repressed, were isolated. The mutations identified clustered within, as well as adjacent to, the Pro41-to-Glu53 sequence. These findings suggest that the conserved Pro41-to-Glu53 sequence is involved in the signal transduction mechanism of EnvZ.

为探明N端序列是否参与EnvZ的跨膜信号转导机制，研究人员对多种肠杆菌来源的envZ基因的核苷酸序列进行了测定。经比较分析发现，Pro41与Glu53之间的氨基酸序列具有高度保守性。为进一步分析该保守序列的功能，研究人员对大肠杆菌（Escherichia coli）的envZ基因进行了随机PCR诱变，并分离得到了可引发高渗表型（即ompF基因表达被抑制）的突变等位基因。经鉴定的突变位点均聚集于Pro41至Glu53序列区域内及其邻近位置。上述研究结果表明，这段高度保守的Pro41至Glu53序列参与了EnvZ的信号转导机制。