CLONING AND PROMOTER IDENTIFICATION OF THE IRON-REGULATED CIR GENE OF ESCHERICHIA-COLI
CLONING AND PROMOTER IDENTIFICATION OF THE IRON-REGULATED CIR GENE OF ESCHERICHIA-COLI
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DOI：
10.1128/jb.169.12.5343-5352.1987
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发表时间：
1987-12-01
影响因子：
3.2
通讯作者：
KONISKY, J
中科院分区：
文献类型：
--
作者：
GRIGGS, DW;THARP, BB;KONISKY, J
cir基因编码大肠杆菌素I受体蛋白，受细胞铁含量和生长温度的调节，该基因被克隆到一个多拷贝数质粒中。物理定位和互补分析确定了mgl和nfo之间的cirr在大肠杆菌染色体上的位置。一个编码32000道尔顿多肽的基因位于cir的下游和邻近，但似乎不是同一转录单位的一部分。来自1.8千碱基对受体编码区5”端的525碱基对片段指导铁调控的cirl - lacz基因的转录和翻译。通过转录起始位点的测定和序列分析，确定了两个重叠的启动子。在受体编码序列之前有一个未知意义的小开放阅读框（120个核苷酸）。对从外膜纯化的受体的氨基酸序列的检查表明，该基因产物是通过去除信号肽而加工的，成熟形式的氨基酸序列在其氨基末端附近与其他几种tonb依赖性蛋白非常相似。
The cir gene, which encodes the colicin I receptor protein and is regulated by both cellular iron content and growth temperature, was cloned into a multicopy-number plasmid. Physical mapping and complementation analysis established the position of cir between mgl and nfo on the Escherichia coli chromosome. A gene encoding a 32,000-dalton polypeptide was located downstream of and adjacent to cir, but did not appear to be part of the same transcriptional unit. A 525-base-pair fragment from the 5'' end of the 1.8-kilobase-pair receptor-coding region directed iron-regulated transcription and translation of a hydrid cir-lacZ gene. Two overlapping promoters were identified by determination of the transcriptional start sites and by sequence analysis. A small open reading frame (120 nucleotides) of unknown significance preceded the receptor-coding sequence. Examination of the amino acid sequence of the receptor purified from the outer membrane revealed that the gene product was processed by removal of a signal peptide and that the mature form had an amino acid sequence near its amino terminus which closely resembled that of several other TonB-dependent proteins.