PARENT SESSION
Posters P1B Photo-oxidative stress, photoinhibition. Abstracts (394-443)

The function of the small Cab-like proteins. Danny Yao^{*,1, 2}, Peter Stenlund¹, Wim Vermaas², Christiane Funk¹, ¹ Department of Biochemistry, Umeå University, Umeå, Sweden² School of Life Sciences and Center for the Study of Early Events in Photosynthesis, Tempe, AZ, USA

ABSTRACT- Chlorophyll a/b binding (Cab) proteins together form the light-harvesting antenna of plants, but members of this extended family also are involved in light regulation. In the genomes of various cyanobacteria small homologues to the Cab genes have been detected, but the function of the corresponding proteins is not known. In the cyanobacterium Synechocystis sp. PCC 6803 the small Cab-like proteins (SCPs) have been found to be involved in the regulation of the tetrapyrrole biosynthesis pathway. Deletion of SCPs reduced the amount of carotenoids as well as chlorophyll. Also the accumulation of the SCPs (or high light induced proteins, HLIPs) is important for the survival during exposure to light stress. SCPs may be important for recycling of chlorophylls upon turnover of photosystem components. Consequently we are using 2D-PAGE followed by mass spectrometry to study the association of the SCPs with Photosystem I and Photosystem II complexes. Also with the help of Biacore the localization as well as the pigment binding ability of the SCPs is investigated.

KEY WORDS: Small Cab-like Proteins, Cyanobacterium, photosystem, pigment binding