Oxender D L, Anderson J J, Daniels C J, Landick R, Gunsalus R P, Zurawski G, Selker E, Yanofsky C
Proc Natl Acad Sci U S A. 1980 Mar;77(3):1412-6. doi: 10.1073/pnas.77.3.1412.
The four genes encoding the components of the high-affinity branched-chain amino acid transport systems in Escherichia coli (livH, livG, livJ, and livK) have been cloned into lambda phage and subsequently into the plasmid vector pACYC184. The presence of the four structural genes and their accompanying regulatory regions on the resultant plasmid, pOXI, was confirmed by genetic complementation and analysis and by transport studies carried out on the appropriate transformed mutant strains. When pOX1 DNA was used to direct an in vitro transcription/translation system, four major polypeptide products were produced. Immunoprecipitation with antibody directed against the LIV-binding protein identified the two leucine-binding proteins as products of in vitro synthesis. The binding proteins were produced in precursor forms and had molecular weights approximately 2500 higher than the processed, mature forms. A minicell-producing strain transformed with plasmid pOX1 produced the binding proteins in the processed form.
编码大肠杆菌中高亲和力支链氨基酸转运系统各组分的四个基因（livH、livG、livJ和livK）已被克隆到λ噬菌体中，随后又克隆到质粒载体pACYC184中。通过遗传互补和分析以及对适当的转化突变菌株进行转运研究，证实了所得质粒pOXI上存在这四个结构基因及其伴随的调控区域。当用pOX1 DNA指导体外转录/翻译系统时，产生了四种主要的多肽产物。用针对LIV结合蛋白的抗体进行免疫沉淀，确定了两种亮氨酸结合蛋白是体外合成的产物。结合蛋白以前体形式产生，其分子量比加工后的成熟形式大约高2500。用质粒pOX1转化的产微小细胞菌株产生加工形式的结合蛋白。
