2 ' 5 ' -oligoadenylate合成酶的酶活性受特定突变影响齐聚反应的蛋白质。
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Ghosh Sarkar SN,郭W, Bandyopadhyay年代,森GC
2 ' 5 ' -oligoadenylate合成酶的酶活性受特定突变影响齐聚反应的蛋白质。
J生物化学杂志。1997年12月26日,272 (52):33220 - 6。
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9407111 (在PubMed]
- 文摘
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从我们实验室之前的研究已经表明,删除残留的321年到344年以同工酶2 ' 5 ' -oligoadenylate (2 - 5 (A))合成酶的酶活性(造成损失Ghosh美国K。Kusari, J。Bandyopadhyay,美国K。Samanta, H。库马尔,R。森,g . c(1991)生物。266年化学,15293 - 15299)。序列比较,这个地区在不同的2 - 5 (A)同功酶合成酶透露,残留在职位330年到333年是高度保守的。Alanine-scanning诱变这些残留物证明残留出席331年,332年和333年对活动很重要但脯氨酸在330年是可有可无的位置。包含阿拉巴马州的三突变体残留在331年,332年和333年完全不活跃。不同的双突变体略活跃,三个单突变体部分活跃。三突变体进一步描述其缺陷的本质特征。突变体蛋白合成了惰性酶无论是在兔网织红细胞溶解产物,大肠杆菌或Trichoplusia倪昆虫细胞。 It could bind double-stranded RNA and ATP as efficiently as the wild type protein. It was, however, defective in oligomerization. Gel filtration and sedimentation velocity analyses of in vitro synthesized proteins revealed that the wild type protein, but not the triple mutant, formed tetramers. The tetrameric fraction, but not the monomeric fraction of the wild type protein was enzymatically active. The failure of the triple mutant to participate in homomeric protein-protein interaction was confirmed by in vivo assays in insect cells. These results indicate that tetramerization of the protein is required for the enzymatic activity of the small 2-5(A) synthetases.