L-glutamate (Glu) is the major excitatory transmitter in mammalian brain. Inadequate concentration of Glu in the brain correlates to mood disorder. In industry, Glu is used as a flavour enhancer in food and in foodstuff processing. A high concentration of Glu has several effects on human health such as hypersensitive effects, headache and stomach pain. The presence of Glu in food can be detected by different analytical methods based on chromatography, or capillary electrophoresis or amperometric techniques. We have isolated and characterized a glutamate-binding protein (GluB) from the Gram-positive bacteria Corynebacterium glutamicum. Together with GluC protein, GluD protein and the cytoplasmic protein GluA, GluB permits the transport of Glu in/out of cell.

In this study, we have investigated the binding features of GluB as well as the effect of temperature on its structure both in the absence and in the presence of Glu. The results have showed that GluB has a high affinity and selectivity versus Glu (nanomolar range) and the presence of the ligand induces a higher thermal stability of the protein structure.

谷氨酸（Glu）是哺乳动物大脑中的主要兴奋性递质。大脑中Glu浓度不足与情绪障碍有关。在工业上，Glu在食品和食品加工中用作增味剂。高浓度的Glu对人体健康有多种影响，例如过敏反应，头痛和胃痛。食品中Glu的存在可以通过基于色谱法，毛细管电泳或安培技术的不同分析方法进行检测。我们已经从革兰氏阳性细菌谷氨酸棒杆菌分离并鉴定了谷氨酸结合蛋白（GluB）。与GluC蛋白，GluD蛋白和细胞质蛋白GluA一起，GluB允许Glu进出细胞。

在这项研究中，我们研究了在不存在和存在Glu的情况下GluB的结合特征以及温度对其结构的影响。结果表明，相对于Glu（纳摩尔范围），GluB具有较高的亲和力和选择性，并且配体的存在可诱导蛋白质结构更高的热稳定性。