Wavelength-dependent photoproduct formation of phycocyanobilin in solution - Indications for competing reaction pathways

作者：Dietzek Benjamin^*; Fey Sonja; Matute Ricardo A; Gonzalez Leticia; Schmitt Michael; Popp Juergen; Yartsev Arkady; Hermann Gudrun

来源：Chemical Physics Letters, 2011, 515(1-3): 163-169.

DOI：10.1016/j.cplett.2011.08.086

Phycocyanobilin (PCB), an open-chain tetrapyrrole, makes up - slightly modified - the chromophore in phytochromes, the importance of which triggered model studies on the photochemistry of PCB in solution. We use pump-wavelength dependent femtosecond transient absorption spectroscopy including the near-IR region for probing to gain new insight into the photoreaction. The data reveal the coexistence of three ground state species: The dominant species PCB(A) undergoes photoreaction into PCB(B) and PCB(C) indicating a branching of the initial reaction path leading to formation of PCB(B) and PCB(C). On this basis the photoreaction involves fast structural rearrangements within the tetrapyrrolic macrocycle, which are followed by slower rate-limiting changes in the protonation state of the pyrrolenine/pyrrole rings.

• 出版日期2011-10-17