AtPTR1, a plasma membrane peptide transporter expressed during seed germination and in vascular tissue of Arabidopsis
AtPTR1, a plasma membrane peptide transporter expressed during seed germination and in vascular tissue of Arabidopsis
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DOI：
10.1111/j.1365-313x.2004.02224.x
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发表时间：
2004-11-01
期刊：
影响因子：
7.2
通讯作者：
Rentsch, D
中科院分区：
文献类型：
--
作者：
Dietrich, D;Hammes, U;Rentsch, D
对于有机氮的有效转运，两到三个氨基酸的小肽被认为是氨基酸的重要替代物。一个新的转运介导的摄取的二肽和三肽的分离，从拟南芥的肽转运缺陷的酿酒酵母突变体的异源互补。AtPTR 1介导S.酿酒酵母细胞对不同的二肽和三肽，并引起敏感性的植物毒素phaseolotoxin。AtPTR 1识别的底物的光谱测定在非洲爪蟾卵母细胞注射AtPTR 1 cRNA电压钳条件下。AtPTR 1不仅识别广谱的二肽和三肽，而且还识别缺乏肽键的底物。然而，氨基酸、ω-氨基脂肪酸或具有三个以上氨基酸残基的肽不与AtPTR 1相互作用。在pH 5.5时，AtPTR 1对Ala-Asp的亲和力（K-0.5 = 416 mum）明显低于Ala-Ala（K-0.5 = 54 mum）和Ala-Lys（K-0.5 = 112 mum）。AtPTR 1/GFP融合蛋白在烟草原生质体中的瞬时表达表明AtPTR 1定位于质膜。此外，在AtPTR 1启动子的控制下表达β-葡萄糖醛酸酶（uidA）基因的转基因植物表现出在整个植物的维管组织中的表达，表明在长距离运输的二肽和三肽的作用。
For the efficient translocation of organic nitrogen, small peptides of two to three amino acids are posited as an important alternative to amino acids. A new transporter mediating the uptake of di- and tripeptides was isolated from Arabidopsis thaliana by heterologous complementation of a peptide transport-deficient Saccharomyces cerevisiae mutant. AtPTR1 mediated growth of S. cerevisiae cells on different di- and tripeptides and caused sensitivity to the phytotoxin phaseolotoxin. The spectrum of substrates recognized by AtPTR1 was determined in Xenopus laevis oocytes injected with AtPTR1 cRNA under voltage clamp conditions. AtPTR1 not only recognized a broad spectrum of di- and tripeptides, but also substrates lacking a peptide bond. However, amino acids, omega-amino fatty acids or peptides with more than three amino acid residues did not interact with AtPTR1. At pH 5.5 AtPTR1 had an apparent lower affinity (K-0.5 = 416 mum) for Ala-Asp compared with Ala-Ala (K-0.5 = 54 mum) and Ala-Lys (K-0.5 = 112 mum). Transient expression of AtPTR1/GFP fusion proteins in tobacco protoplasts showed that AtPTR1 is localized at the plasma membrane. In addition, transgenic plants expressing the beta-glucuronidase (uidA) gene under control of the AtPTR1 promoter demonstrated expression in the vascular tissue throughout the plant, indicative of a role in long-distance transport of di- and tripeptides.