Bioinformatic and Functional Analysis of a Key Determinant Underlying the Substrate Selectivity of the Al Transporter, Nrat1.
Bioinformatic and Functional Analysis of a Key Determinant Underlying the Substrate Selectivity of the Al Transporter, Nrat1.
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AI 转运蛋白 Nrat1 底物选择性的关键决定因素的生物信息学和功能分析
DOI：
10.3389/fpls.2018.00606
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发表时间：
2018
影响因子：
5.6
通讯作者：
Xia J
中科院分区：
文献类型：
--
作者：
Lu M;Yang G;Li P;Wang Z;Fu S;Zhang X;Chen X;Shi M;Ming Z;Xia J
Nrat1是所有生物体中天然抗性相关巨噬细胞蛋白（Nramp）金属离子转运蛋白家族的成员。与其他能够转运二价金属的Nramp成员不同，Nrat1特异性转运三价铝（Al）离子。然而，Nrat1铝转运选择性的分子机制仍然未知。在此，我们对Nrat1和其他Nramp成员进行了结构 - 功能分析，以深入了解离子选择性的决定因素。系统发育分析表明，植物Nramp转运蛋白可分为五组。在进化树上，OsNrat1位于其中一个单独的分支中，并与SbNrat1和ZmNrat1聚类。结构建模显示，Nrat1转运蛋白采用了许多Nramp家族转运蛋白共有的LeuT折叠结构，可能采用相同的转运机制。氨基酸的序列比对和进化保守性分析确定了以金属结合位点为中心的Nrat1金属渗透途径。Nrat1的金属结合位点具有两个保守的序列基序，即Asp - Pro - Ser - Asn基序（基序A）和Ala - Ile - Ile - Thr基序（基序B）。将OsNramp3锰（Mn）转运蛋白的Ala - Met - Val - Met基序B替换为Nrat1的基序B，导致酵母中铝转运活性部分获得且锰完全丧失。相反，用OsNramp3的基序B替换OsNrat1的基序B改变了铝转运活性。这些观察结果表明金属结合位点，特别是基序B，是Nrat1铝选择性的关键决定因素。
Nrat1 is a member of the natural resistance-associated macrophage protein (Nramp) family of metal ion transporters in all organisms. Different from other Nramp members capable of transporting divalent metals, Nrat1 specifically transports trivalent aluminum (Al) ion. However, molecular mechanism underlying the Al transport selectivity of Nrat1 remains unknown. Here, we performed structure-function analyses of Nrat1 and other Nramp members to gain insights into the determinants of ion selectivity. A phylogenetic analysis showed that plant Nramp transporters could be divided into five groups. OsNrat1 was found in one of the individual clades and clustered with SbNrat1 and ZmNrat1 on the evolutionary tree. Structural modeling revealed that Nrat1 transporters adopted a common LeuT fold shared by many Nramp-family transporters that likely employed an identical transport mechanism. Sequence alignment and evolutionary conservation analysis of amino acids identified a metal-permeation pathway of Nrat1 centered at the metal binding site. The metal binding site of Nrat1 was characterized by two conserved sequence motifs, i.e., the Asp-Pro-Ser-Asn motif (motif A) and the Ala-Ile-Ile-Thr motif (motif B). Replacement of the Ala-Met-Val-Met motif B of the OsNramp3 manganese (Mn) transporter to that of Nrat1 resulted in a partial gain of Al transport activity and a total loss of Mn in yeast. Conversely, substitution of the motif B of OsNrat1 with that of OsNramp3 altered the Al transport activity. These observations indicated the metal binding site, particularly the motif B, as a key determinant of Al selectivity of Nrat1.
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影响因子：
7.4
作者：
Lanquar, Viviane;Ramos, Magali Schnell;Thomine, Sebastien
通讯作者：
Thomine, Sebastien
影响因子：
14.8
作者：
通讯作者：
--
DOI：
10.1073/pnas.97.9.4991
发表时间：
2000-04-25
影响因子：
11.1
作者：
Thomine, S;Wang, RC;Schroeder, JI
通讯作者：
Schroeder, JI
影响因子：
16.8
作者：
Ehrnstorfer, Ines A.;Geertsma, Eric R.;Dutzler, Raimund
通讯作者：
Dutzler, Raimund
影响因子：
10.7
作者：
SAITOU, N;NEI, M
通讯作者：
NEI, M