Conrad Karen S, Manahan Craig C, Crane Brian R
Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York, USA.
Nat Chem Biol. 2014 Oct;10(10):801-9. doi: 10.1038/nchembio.1633.
Three major classes of flavin photosensors, light oxygen voltage (LOV) domains, blue light sensor using FAD (BLUF) proteins and cryptochromes (CRYs), regulate diverse biological activities in response to blue light. Recent studies of structure, spectroscopy and chemical mechanism have provided unprecedented insight into how each family operates at the molecular level. In general, the photoexcitation of the flavin cofactor leads to changes in redox and protonation states that ultimately remodel protein conformation and molecular interactions. For LOV domains, issues remain regarding early photochemical events, but common themes in conformational propagation have emerged across a diverse family of proteins. For BLUF proteins, photoinduced electron transfer reactions critical to light conversion are defined, but the subsequent rearrangement of hydrogen bonding networks key for signaling remains highly controversial. For CRYs, the relevant photocycles are actively debated, but mechanistic and functional studies are converging. Despite these challenges, our current understanding has enabled the engineering of flavoprotein photosensors for control of signaling processes within cells.
三类主要的黄素光传感器，即光氧电压（LOV）结构域、使用黄素腺嘌呤二核苷酸（FAD）的蓝光传感器（BLUF）蛋白和隐花色素（CRY），可响应蓝光调节多种生物活性。最近关于结构、光谱学和化学机制的研究为每个家族在分子水平上的运作方式提供了前所未有的见解。一般来说，黄素辅因子的光激发会导致氧化还原和质子化状态的变化，最终重塑蛋白质构象和分子相互作用。对于LOV结构域，早期光化学事件仍存在问题，但在不同蛋白质家族中已出现构象传播的共同主题。对于BLUF蛋白，已确定了对光转换至关重要的光诱导电子转移反应，但对于信号传导关键的氢键网络的后续重排仍存在很大争议。对于CRY，相关的光循环仍在激烈争论，但机理和功能研究正在趋同。尽管存在这些挑战，我们目前的理解已使黄素蛋白光传感器的工程设计能够用于控制细胞内的信号传导过程。
