Harper Shannon M, Neil Lori C, Gardner Kevin H
Departments of Biochemistry and Pharmacology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9038, USA.
Science. 2003 Sep 12;301(5639):1541-4. doi: 10.1126/science.1086810.
Phototropins are light-activated kinases important for plant responses to blue light. Light initiates signaling in these proteins by generating a covalent protein-flavin mononucleotide (FMN) adduct within sensory Per-ARNT-Sim (PAS) domains. We characterized the light-dependent changes of a phototropin PAS domain by solution nuclear magnetic resonance spectroscopy and found that an alpha helix located outside the canonical domain plays a key role in this activation process. Although this helix associates with the PAS core in the dark, photoinduced changes in the domain structure disrupt this interaction. We propose that this mechanism couples light-dependent bond formation to kinase activation and identifies a signaling pathway conserved among PAS domains.
向光素是对植物蓝光反应很重要的光激活激酶。光通过在感官性的Per-ARNT-Sim（PAS）结构域内生成共价蛋白 - 黄素单核苷酸（FMN）加合物来启动这些蛋白中的信号传导。我们通过溶液核磁共振光谱对向光素PAS结构域的光依赖性变化进行了表征，发现位于经典结构域之外的一个α螺旋在这个激活过程中起关键作用。尽管这个螺旋在黑暗中与PAS核心结合，但该结构域结构的光诱导变化会破坏这种相互作用。我们提出这种机制将光依赖性键的形成与激酶激活联系起来，并确定了PAS结构域之间保守的信号传导途径。
