The crystal structure of plant-specific calcium-binding protein AtCBL2 in complex with the regulatory domain of AtCIPK14
The crystal structure of plant-specific calcium-binding protein AtCBL2 in complex with the regulatory domain of AtCIPK14
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DOI：
10.1016/j.jmb.2008.01.006
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发表时间：
2008-03-14
影响因子：
5.6
通讯作者：
Shimizu, Toshiyuki
中科院分区：
文献类型：
--
作者：
Akaboshi, Mayuko;Hashimoto, Hiroshi;Shimizu, Toshiyuki
钙信号介导植物对外界刺激的多种反应。类钙调磷酸酶B（CBL）蛋白及其靶激酶CBL相互作用蛋白激酶（CIPKs）是植物钙信号传导的重要中继。CBL通过C-末端调控结构域内的保守基序（NAF/FISL基序）与CIPK相互作用。为了更好地理解CBL-CIPK系统的功能作用，我们以1.2埃的分辨率确定了AtCBL 2与AtCIPK 14的调节结构域复合的晶体结构。NAF/FISL基序插入AtCBL 2内的疏水缝隙中，伴随着NAF/FISL基序相对侧上的螺旋和环从C-末端区域的大位移，其以游离形式屏蔽疏水缝隙。Ca ~（2+）以结合形式配位在AtCBL 2的四个EF手内。这种钙配位模式不同于先前报道的SOS 3-SOS 2复合物的结构。两种结构的结构比较表明，CIPK对CBL的识别以类似的方式进行，但固有的相互作用赋予结合亲和力和特异性。(c)2008爱思唯尔有限公司保留所有权利。
Calcium signals mediate a multitude of plant responses to external stimuli. Calcineurin B-like (CBL) proteins and their target kinases, CBL-interacting protein kinases (CIPKs), represent important relays in plant calcium signaling. CBL interacts with CIPK through a conserved motif (NAF/FISL motif) within the C-terminal regulatory domain. To better understand the functional role of the CBL-CIPK system, we determined the crystal structure of AtCBL2 in complex with the regulatory domain of AtCIPK14 at 1.2 angstrom resolution. The NAF/FISL motif is inserted into a hydrophobic crevice within AtCBL2, accompanied by a large displacement of the helices and loop on the opposite side of the NAF/FISL motif from the C-terminal region, which shields the hydrophobic crevice in free form. Ca2+ are coordinated within four EF hands in AtCBL2 in bound form. This calcium coordination pattern differs from that in the structure of the SOS3-SOS2 complex previously reported. Structural comparison of the two structures shows that the recognition of CBL by CIPK is performed in a similar manner, but inherent interactions confer binding affinity and specificity. (c) 2008 Elsevier Ltd. All rights reserved.