Sensor modules of the osmoregulatory glycine betaine uptake carrier from Corynebacterium glutamicum: structure and interaction with the transport domain Transport-Domäne

谷氨酸棒状杆菌紧密耦合的甜菜碱摄取系统BetP将电化学Na+梯度的能量转化为极高的甜菜碱化学梯度。BetP的活性严格依赖于跨质膜渗透梯度的存在。BetP同时是渗透传感器和转运体。转运蛋白是一种膜蛋白，具有12个跨膜片段，包括面向细胞质的显著N端和c端延伸，这是在许多前核和真核渗透活性膜蛋白中观察到的特性。这些扩展已被证明与传感器功能有关。N端和c端模块将分别以不同长度表示，BetP的膜嵌部分也将分别表示。我们建议利用各种光谱技术，特别是核磁共振光谱和x射线晶体学来研究BetP亲水模块的结构及其与输运域的结构相互作用。

The tightly coupled betaine uptake system BetP of Corynebacterium glutamicum converts the energy of an electrochemical Na+ gradient into an extremely high chemical gradient of betaine. The activity of BetP strictly depends on the presence of an osmotic gradient across the plasma membrane. BetP was shown to be both osmosensor and transporter. The transporter is a membrane protein with 12 transmembrane segments and includes prominent N- and C-terminal extensions facing the cytoplasm, a property observed in many pro- and eukarytic osmoactive membrane proteins. These extensions have been shown to be involved in the sensor function. The N- and C-terminal modules will be separately expressed in different lengths, as well as the membrane-embedded part of BetP. We propose to study the structure of the hydrophilic modules of BetP and its structural interaction with the transport domain by using various spectroscopic techniques, in particular NMR spectroscopy, and also X-ray crystallography.