Structure and mechanism of a bacterial light-regulated cyclic nucleotide phosphodiesterase
Structure and mechanism of a bacterial light-regulated cyclic nucleotide phosphodiesterase
复制标题
DOI：
10.1038/nature07966
复制
发表时间：
2009-06-18
期刊：
影响因子：
64.8
通讯作者：
Schlichting, Ilme
中科院分区：
文献类型：
--
作者：
Barends, Thomas R. M.;Hartmann, Elisabeth;Schlichting, Ilme
对光的反应能力对大多数生物体来说至关重要。BLUF是最近鉴定的光感受器蛋白结构域，其使用FAD发色团感知蓝光（1）。BLUF结构域存在于来自细菌、裸藻和真菌的各种蛋白质中。尽管已经确定了单结构域BLUF蛋白的结构（2-4），但是没有一个可用于含有功能输出结构域的BLUF蛋白;因此，对这类新的光感受器中的光激活机制仍然知之甚少。在这里，我们报告了来自肺炎克雷伯氏菌的全长活性光感受器BlrP 1（也称为KPN_01598）的生化、结构和机制表征（5）。BlrP 1由BLUF传感器结构域和水解环状二聚GMP（c-di-GMP）的磷酸二酯酶EAL输出结构域组成。这种普遍存在的第二信使控制细菌中的运动性、生物膜形成、毒力和抗生素抗性（6-9）。BlrP 1与其底物和参与催化或酶抑制的金属离子复合的晶体结构提供了对EAL结构域c-di-GMP磷酸二酯酶机制的详细理解。这些结构也勾画出了光激活磷酸二酯酶输出活性的路径。反平行BlrP 1同源二聚体的一个亚基的BLUF结构域的光子吸收通过保守结构域-结构域界面传输的变构通信激活第二亚基的EAL结构域。
The ability to respond to light is crucial for most organisms. BLUF is a recently identified photoreceptor protein domain that senses blue light using a FAD chromophore(1). BLUF domains are present in various proteins from the Bacteria, Euglenozoa and Fungi. Although structures of single-domain BLUF proteins have been determined(2-4), none are available for a BLUF protein containing a functional output domain; the mechanism of light activation in this new class of photoreceptors has thus remained poorly understood. Here we report the biochemical, structural and mechanistic characterization of a full-length, active photoreceptor, BlrP1 (also known as KPN_01598), from Klebsiella pneumoniae(5). BlrP1 consists of a BLUF sensor domain and a phosphodiesterase EAL output domain which hydrolyses cyclic dimeric GMP (c-di-GMP). This ubiquitous second messenger controls motility, biofilm formation, virulence and antibiotic resistance in the Bacteria(6-9). Crystal structures of BlrP1 complexed with its substrate and metal ions involved in catalysis or in enzyme inhibition provide a detailed understanding of the mechanism of the EAL-domain c-di-GMP phosphodiesterases. These structures also sketch out a path of light activation of the phosphodiesterase output activity. Photon absorption by the BLUF domain of one subunit of the antiparallel BlrP1 homodimer activates the EAL domain of the second subunit through allosteric communication transmitted through conserved domain-domain interfaces.