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目的铁氧还蛋白系铁硫蛋白,在多种反应体系中起着传递电子的作用,也参与抗滴虫药物甲硝咪唑杀虫作用的激活。本研究旨在克隆和分析阴道毛滴虫铁氧还蛋白基因,以便进一步探讨其生理功能。方法构建阴道毛滴虫cDNA表达文库,分离cDNA进行克隆、测序及序列分析。结果在分离出的cDNA克隆中发现一个新的铁氧还蛋白基因。该基因读码框全长312bp,相应蛋白质序列具103个氨基酸;在该蛋白质前体的N端带有10个氨基酸残基的氢酶体靶片段(MLSQCSPLRF)。序列分析显示该铁氧还蛋白(TvFd2)与已报道的阴道毛滴虫铁氧还蛋白(TvFd)有高度同源性(69%);TvFd2与铁氧还蛋白(2Fe-2S)的两大亚类(氧化酶铁氧还蛋白和光合铁氧还蛋白)均具较低的同源性;可与(2Fe-2S)结合的4个半胱氨酸排列成典型的铁氧还蛋白保守序列(-C-X5-C-X2-C-Xn-C-)。结论分析表明TvFd2是一新的阴道毛滴虫铁氧还蛋白,其功能有待进一步研究。
The target ferredoxin, an iron-sulfur protein, plays a role in transmitting electrons in various reaction systems and is also involved in the activation of the anti-trichomonad metronidazole insecticidal effect. This study aimed to clone and analyze the gene of ferredoxin of Trichomonas vaginalis, in order to further explore its physiological function. Methods Construction of Trichomonas vaginalis cDNA expression library, cDNA was isolated for cloning, sequencing and sequence analysis. As a result, a new ferredoxin gene was found in the isolated cDNA clone. The full-length reading frame of this gene is 312bp, with 103 amino acids corresponding to the protein sequence. A 10-amino acid residue target fragment (MLSQCSPLRF) is provided at the N-terminus of the protein precursor. Sequence analysis showed that the ferredoxin (TvFd2) had high homology (69%) with reported Trichomonas vaginalis ferredoxin (TvFd); the two major TvFd2 and ferredoxin (2Fe-2S) Subtypes (oxidoreductase and photosynthetic ferredoxin) all have lower homology; the four cysteines that can bind to (2Fe-2S) are arranged in a typical ferredoxin conserved sequence (-C-X5-C-X2-C-Xn-C-). Conclusion The analysis shows that TvFd2 is a new Trichomonas vaginalis ferredoxin, its function needs further study.