Characterization of a Functionally Unknown Arginine-Aspartate-Aspartate Family Protein From Halobacillus andaensis and Functional Analysis of Its Conserved Arginine/Aspartate Residues.
Characterization of a Functionally Unknown Arginine-Aspartate-Aspartate Family Protein From Halobacillus andaensis and Functional Analysis of Its Conserved Arginine/Aspartate Residues.
复制标题
安达盐杆菌中功能未知的精氨酸-天冬氨酸-天冬氨酸家族蛋白的表征及其保守的精氨酸/天冬氨酸残基的功能分析
DOI：
10.3389/fmicb.2018.00807
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发表时间：
2018
影响因子：
5.2
通讯作者：
Jiang J
中科院分区：
文献类型：
--
作者：
Shao L;Abdel-Motaal H;Chen J;Chen H;Xu T;Meng L;Zhang Z;Meng F;Jiang J
精氨酸-天冬氨酸-天冬氨酸(RDD)家族是一类由一个高度保守的精氨酸和两个高度保守的天冬氨酸组成的跨膜蛋白，其功能尚未确定。在这里，我们描述了该家族中一个命名为RDD的成员，该成员来自中度嗜盐安达氏嗜盐杆菌NEU-ST10-40T，并首次报道了RDD作为一种新的Na+(Li+，K+)/H+逆向转运蛋白的功能。更有趣的是，无论是整个家族中高度保守的精氨酸/天冬氨酸残基，还是RDD与其选定的同源物之间的高度保守残基与蛋白质功能有关。因此，我们通过定点突变分析了它们在阳离子转运活性中的作用，发现D154、R124、R129和D158是Na+(Li+，K+)/H+反转运活性所必需的，而R35和D42都不参与Na+(Li+，K+)/H+反转运活性。作为Na+(Li+，K+)/H+逆向转运蛋白和RDD家族蛋白的双重代表，RDD的特性及其重要残基的分析将有助于了解这一新的逆向转运蛋白的阳离子转运机制以及高度保守的精氨酸/天冬氨酸残基在RDD家族蛋白功能中的作用。
Arginine–aspartate–aspartate (RDD) family, representing a category of transmembrane proteins containing one highly conserved arginine and two highly conserved aspartates, has been functionally uncharacterized as yet. Here we present the characterization of a member of this family designated RDD from the moderate halophile Halobacillus andaensis NEAU-ST10-40T and report for the first time that RDD should function as a novel Na+(Li+, K+)/H+ antiporter. It’s more interesting whether the highly conserved arginine/aspartate residues among the whole family or between RDD and its selected homologs are related to the protein function. Therefore, we analyzed their roles in the cation-transporting activity through site-directed mutagenesis and found that D154, R124, R129, and D158 are indispensable for Na+(Li+, K+)/H+ antiport activity whereas neither R35 nor D42 is involved in Na+(Li+, K+)/H+ antiport activity. As a dual representative of Na+(Li+, K+)/H+ antiporters and RDD family proteins, the characterization of RDD and the analysis of its important residues will positively contribute to the knowledge of the cation-transporting mechanisms of this novel antiporter and the roles of highly conserved arginine/aspartate residues in the functions of RDD family proteins.