Here, proteins involved in sulfur-containing amino acid uptake in Escherichia coli strains were investigated with the aim of applying the findings in fermentative amino acid production. A search of genes in an l-methionine auxotrophic strain library suggested YecSC as the putative transporter of l-cystathionine. l-Methionine production increased by 15% after amplification of yecSC in producer strains. A candidate protein responsible for l-cysteine uptake was also found by experimentation with multicopy suppressor E. coli strains that recovered from growth defects caused by l-cysteine auxotrophy. Based on the results of an uptake assay, growth using l-cysteine as a sole sulfur source, and sensitivity to l-cysteine toxicity, we proposed that YeaN is an l-cysteine transporter. l-Cysteine production increased by 50% as a result of disrupting yeaN in producer strain. The study of amino acid transporters is valuable to industrialized amino acid production and also sheds light on the role of these transporters in sulfur assimilation.

在此，研究了在大肠杆菌菌株中参与含硫氨基酸吸收的蛋白质，目的是将这些发现应用于发酵氨基酸的生产。在l-蛋氨酸营养缺陷型菌株文库中对基因的搜索表明，YecSC是l-胱氨酸蛋氨酸的推定转运蛋白。在生产菌株中扩增yecSC后，1M乙硫氨酸产量增加了15％。负责候选蛋白质1-半胱氨酸摄取也通过实验用多拷贝抑制发现大肠杆菌，从引起的生长缺陷的菌株中回收1-半胱氨酸营养缺陷型。根据摄取分析的结果，使用l-半胱氨酸作为唯一硫源的生长以及对l-半胱氨酸毒性的敏感性，我们提出YeaN是l-半胱氨酸转运蛋白。1-半胱氨酸生产增加了50％作为破坏的结果YEAN在生产菌株。氨基酸转运蛋白的研究对氨基酸的工业化生产具有重要意义，同时也阐明了这些转运蛋白在硫同化中的作用。