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 PCBA undergoes photoreaction into PCBB and PCBC indicating a branching of the initial reaction path leading to formation of PCBB and PCBC. 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. (C) 2011 Elsevier B.V. All rights reserved.
Bibliographical noteThe information about affiliations in this record was updated in December 2015.
The record was previously connected to the following departments: Chemical Physics (S) (011001060)
Subject classification (UKÄ)
- Atom and Molecular Physics and Optics