Structural Analysis of Ethylene (Plant Hormone) Sensor Protein

乙烯是一种植物激素，它与植物的生活史密切相关。乙烯通过与其传感蛋白ETR1结合而表现出其生理活性。ETR1属于细胞内的双组分调控系统，主要由两个功能结构域组成：感受器结构域和组氨酸激酶结构域。最近，已经发现ETR 1传感器域含有Cu（I）。在本项目中，我们一直试图获得Cu（I）是ETR1的乙烯结合位点的直接证据。我们构建了ETR1传感结构域（跨膜蛋白）的重组蛋白在大肠杆菌中的表达系统。coli，建立了纯化方法，并测定了Cu的K边XAFS谱。在乙烯存在和不存在的情况下，光谱显着不同，表明乙烯结合到ETR 1的Cu（I）位点，并导致其配位结构的变化。

Ethylene is a plant hormone, which is significantly involved in life cycle of plants. Ethylene exhibits its physiological activities by virtue of binding to its sensor protein, ETR1. ETR1 belongs to the two-component regulatory system in cells, and mainly consists of two functional domain, sensor domain and histidine kinase domain. Most recently, it has been found that the ETR1 sensor domain contains Cu(I). In the present project,we have been trying to obtain the direct evidence that Cu(I) is the ethylene binding site of ETR1. We constructed expression system of the recombinant protein of the ETR1 sensor domain (trans-membrane protein) in E. coli, established it purification procedure, and measured the Cu K-edge XAFS spectra. The spectra is significantly different in the presence and absence of ethylene, showing that ethylene bind to the Cu(I) sitel of ETR1 and causes its coordination structural changes.