Regensburg 2019 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 3: Bioimaging and biospectroscopy I

BP 3.6: Vortrag

Montag, 1. April 2019, 10:45–11:00, H11

Light induced phycobiliprotein dynamics in Halomicronema hongdechloris adapted to far red light — •Franz-Josef Schmitt and Züleyha Yenice Campbell — Technische Universität Berlin, Sekr. PC 14, Straße des 17. Juni 135, 10623 Berlin

The phototrophic cyanobacterium Halomicronema hongdechloris contains chlorophyll a and f in photosystem II when it is grown under far red light conditions (> 720 nm). In former studies we had shown that the phycobiliproteins (PBS) exhibit effcient excitation energy transfer (EET) to Chl a and Chl f within 200 ps if H. hongdechloris grown under far red light is illuminated with 630 nm. After adaption to far red light the PBS are localized in separated clusters of the cell. Short illumination with blue light (405 nm) leads to a mobilization of the PBS on the time scales of seconds. The PBS quickly appear completely decoupled from the photosystem II (PS II) for several seconds and subsequently recouple to the PS II with recovery of the EET from PBS to PS II within seconds.

We assume that production of reactive oxygen species (ROS) leads to mobilization and recoupling of the PBP antenna complexes after the cells had been adapted to far red light conditions. In parallel high content of carotenoids is found in H. hongdechloris grown under far red light. We present a quantitative analysis of the PBP mobility in dependence of the applied light intensity and wavelength.