A novel strategy for the elucidation of interaction between biologically active amino acids and/or peptides and their receptor proteins.

(1)蜘蛛毒素阻断神经传递机制的研究--蜘蛛毒素荧光标记类似物的合成1)合成NPTX-594类似物，将NPTX-594右端赖氨酸残基的α-或ε-氨基替换为4-硝基苯并-2-氧杂-1，3-二唑作为荧光标记基团。此外，还合成了NPTX-594的左端2，4-二羟基苯乙酸(DHPA)残基被NBD取代的类似物。然而，这些类似物并没有表现出抗蟋蟀的麻痹活性。2)接下来，我们合成了类似物，其中DHPA残基被7-羟基香豆素-3-甲酰基取代。这个类似物的活性是NPTX-594的1/10，似乎是一个很有希望的化合物，用于阐明蜘蛛毒素阻断神经传递的机制。(2)阐明霉酸向植物体内运输Fe(III)的机制。1)利用一个表达玉米中Fe(III)复合转运蛋白ZmYS1 fond的铁吸收缺陷酵母突变体，检测了五个脱氧变酸(DMA)类似物的Fe(III)转运活性。因此，我们认为MA分子中3“-碳原子的立体化学对于形成MA和DMA类似物的Fe(III)配合物的活性结构可能是重要的。2)我们合成了两个分别标记为NBD和/或HCC的DMA类似物作为荧光基团。然而，这些类似物的活性尚不清楚，因为它们可能不能形成Fe(III)络合物，因为它们在水中的溶解性很差。我们目前正在合成新的可溶于水的荧光标记类似物。

In the present project, we studied to develop a novel strategy for the elucidation of interaction between biologically active amino acids and/or peptides and their receptor proteins.(1)Elucidation of a blocking mechanism of neurotransmission by spider toxins - Synthesis of fluorescent labeled analogs of a spider toxin1)The NPTX-594 analog, in which the α- or ε-amino group of the Lys residue at right terminus in NPTX-594 was substituted with 4-nitrobenzo-2-oxa-1,3-diazole (NBD) as the fluorescent labeling group, was synthesized. Furthermore, the analog, in which the 2,4-dihydroxyphenyl acetic acid (Dhpa) residue at left terminus in NPTX-594 was substituted with NBD, was also synthesized. However, these analogs did not show the paralytic activity against cricket.2)We next synthesized the analog in which the Dhpa residue was substituted with the 7-hydroxycoumarin-3-carbonyl (HCC) group. This analog shows the activity of 1/10 potent compared with NPTX-594, and seems to be quite promising compound for the elucidation of a blocking mechanism of neurotransmission by spider toxins.(2)Elucidation of the Fe(III) ion transporting mechanism into plant body by mugineic acid.1) Fe(III) transporting activity of five deoxymugineic acid (DMA) analogs was examined by the use of an iron uptake-defective yeast mutant in which Fe(III) complex transporter ZmYS1 fond in maize was expressed. As a result of this study, we suggest that the stereochemistry at 3"-carbon atom in the MA molecule may be important to form the active structure for the Fe(III) complexes of MA and DMA analogs.2) We synthesized two DMA analogs labeled with NBD and/or HCC as the fluorescent group, respectively. However, the activities of these analogs were not clear, since they may be not able to form Fe(III) complex due to their poor solubility in water. We are currently synthesizing novel fluorescent labeled analogs being soluble in water.