Characterization of a functional bacterial homologue of sodium-dependent neurotransmitter transporters
Characterization of a functional bacterial homologue of sodium-dependent neurotransmitter transporters
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DOI：
10.1074/jbc.m206563200
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发表时间：
2003-04-11
影响因子：
4.8
通讯作者：
Rudnick, G
中科院分区：
文献类型：
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作者：
Androutsellis-Theotokis, A;Goldberg, NR;Rudnick, G
嗜热共生菌的tnaT基因编码一种与钠依赖性神经递质转运蛋白同源的蛋白质。tnaT基因产物在大肠杆菌中的表达赋予了从培养基中积累色氨酸的能力，以及以色氨酸作为唯一碳源生长的能力。转运是Na+依赖性和高度选择性的。色氨酸的K-m近似于145 nM，在其他氨基酸浓度为100 muM的情况下，色氨酸的转运没有变化。色胺和血清素是弱抑制剂，K-I值分别为200和440 muM。通过基于T7启动子的系统，具有n端His(6)标签的TnaT在膜中高水平表达，并在高产量下纯化到接近均匀性。
The tnaT gene of Symbiobacterium thermophilum encodes a protein homologous to sodium-dependent neurotransmitter transporters. Expression of the tnaT gene product in Escherichia coli conferred the ability to accumulate tryptophan from the medium and the ability to grow on tryptophan as a sole source of carbon. Transport was Na+-dependent and highly selective. The K-m for tryptophan was similar to145 nM, and tryptophan transport was unchanged in the presence of 100 muM concentrations of other amino acids. Tryptamine and serotonin were weak inhibitors with K-I values of 200 and 440 muM, respectively. By using a T7 promoter-based system, TnaT with an N-terminal His(6) tag was expressed at high levels in the membrane and was purified to near-homogeneity in high yield.