Spillane Katelyn M, Dasgupta Jyotishman, Lagarias J Clark, Mathies Richard A
Department of Chemistry, University of California, Berkeley, California 94720, USA.
J Am Chem Soc. 2009 Oct 7;131(39):13946-8. doi: 10.1021/ja905822m.
Phytochromes are an important class of red/far-red responsive photoreceptors that act as light-activated biological switches, ultimately driving growth and development in plants, bacteria, and fungi. The composition of the red-absorbing ground-state has been widely debated due to the presence of a shoulder feature on the blue edge of electronic absorption spectra, which many have attributed to the presence of multiple ground-state conformers. Here we use resonance Raman intensity analysis to calculate the vibronic absorption profile of cyanobacterial phytochrome Cph1 and show that this shoulder feature is due simply to vibronic transitions from a single species, thus reflecting a homogeneous ground-state population.
光敏色素是一类重要的对红光/远红光有响应的光感受器，它们作为光激活的生物开关，最终驱动植物、细菌和真菌的生长与发育。由于电子吸收光谱的蓝边存在一个肩峰特征，吸收红光的基态组成一直存在广泛争议，许多人将其归因于多种基态构象体的存在。在这里，我们使用共振拉曼强度分析来计算蓝藻光敏色素Cph1的振动吸收谱，并表明这个肩峰特征仅仅是由于单一物种的振动跃迁所致，从而反映了一个均匀的基态群体。
