生物谷报道：谷氨酸转运分子（Glutamate transporters）在大脑和周围神经系统中扮演一个重要角色，利用离子梯度来在谷氨酸盐从突触前神经元中释放之后将其从突触缝隙中清除掉。现在，Yernool等人确定了一种细菌的谷氨酸盐运输分子的晶体结构，该分子与人类的谷氨酸盐运输分子EAAT2有37%的相同点，其晶体结构让我们清楚地看到了这些运输神经传输物质的分子是如何工作的。该分子有一个引人注目的结构：它是一个简单的碗形三聚物，其作用是作为水溶剂的一个容器，这个容器半穿过细胞膜。“碗”的底部有三个基质结合点，其侧面为发卡状的螺旋体，它们的同步运动可能是交替接触细胞膜两边的关键。
Glutamate transporters are integral membrane proteins that catalyse the concentrative uptake of glutamate from the synapse to intracellular spaces by harnessing pre-existing ion gradients. In the central nervous system glutamate transporters are essential for normal development and function, and are implicated in stroke, epilepsy and neurodegenerative diseases. Here we present the crystal structure of a eukaryotic glutamate transporter homologue from Pyrococcus horikoshii. The transporter is a bowl-shaped trimer with a solvent-filled extracellular basin extending halfway across the membrane bilayer. At the bottom of the basin are three independent binding sites, each cradled by two helical hairpins, reaching from opposite sides of the membrane. We propose that transport of glutamate is achieved by movements of the hairpins that allow alternating access to either side of the membrane.
