Magnesium (Mg²⁺) plays a critical role in many physiological processes. The AtMRS2/MGT family, which contains nine Arabidopsis genes (and two pseudogenes), belongs to a eukaryotic subset of the CorA superfamily of divalent cation transporters. AtMRS2-11/MGT10 possesses the signature GlyMetAsn sequence (the GMN motif) conserved in the CorA superfamily; however, little is known about the role of the GMN motif in AtMRS2. Direct measurement using the fluorescent dye mag-fura-2 revealed that reconstituted AtMRS2-11 mediated rapid Mg²⁺ uptake into proteoliposomes at extraliposomal Mg²⁺ concentrations of 10 and 20 mM. Mutations in the GMN motif, G417 to A, S or V, did not show a significant change in Mg²⁺ uptake relative to the wild-type protein. The G417W mutant exhibited a significant increase in Mg²⁺ uptake. The functional complementation assay in Escherichia coli strain TM2 showed that E. coli cells expressing AtMRS2-11 with mutations in G of the GMN motif did not grow in LB medium without Mg²⁺ supplementation, while growth was observed in LB medium supplemented with 0.5 mM Mg²⁺; no difference was observed between the growth of TM2 cells expressing the AtMRS2-11 G417W mutant and that of cells expressing wild-type AtMRS2-11. These results suggested that the Mg²⁺ transport activity of the AtMRS2-11 GMN-motif mutants was low at low physiological Mg²⁺ concentrations; thus, the Gly residue is critical for Mg²⁺ transport, and the Mg²⁺ transport activity of the GMN-motif mutants was increased at high Mg²⁺ concentrations.

镁（Mg ²⁺）在许多生理过程中起着至关重要的作用。AtMRS2 / MGT家族包含9个拟南芥基因（和2个假基因），属于二价阳离子转运蛋白CorA超家族的真核子集。AtMRS2-11 / MGT10具有在CorA超家族中保守的签名GlyMetAsn序列（GMN基序）；然而，人们对GMN基序在AtMRS2中的作用了解甚少。使用荧光染料mag-fura-2进行的直接测量显示，重组脂质体Mg ^2+的浓度为10和20 mM时，重构的AtMRS2-11介导的Mg ²⁺迅速吸收到脂质体中。GMN基序中的G417突变为A，S或V，但未显示Mg ²⁺的显着变化相对于野生型蛋白质的摄取。G417W突变体表现出Mg ²⁺摄取的显着增加。大肠杆菌TM2菌株中的功能互补分析表明，在未添加Mg ^2+的LB培养基中，表达AtMRS2-11且GMN基序的G突变的大肠杆菌细胞没有生长，而在添加0.5 mM的LB培养基中观察到了生长镁²⁺ ; 表达AtMRS2-11 G417W突变体的TM2细胞的生长与表达野生型AtMRS2-11的细胞的生长之间没有差异。这些结果表明AtMRS2-11 GMN基序突变体的Mg ²⁺转运活性在低生理Mg ²⁺时较低。浓度 因此，Gly残基对于Mg ²⁺转运至关重要，并且在高Mg ²⁺浓度下，GMN-motif突变体的Mg ²⁺转运活性增加。