Low temperature spectroscopy and hole-burning study of iron-stress inducedchlorophyll protein CP 34 of Synechococcus elongatus

Numerous autotrophic organisms alter the composition and function of their photosynthetic apparatus under external stress conditions. This is also the case of the cyanobacterial response to iron deprivation that includes (bes ides other changes) the synthesis of a new, iron-stress induced chlorophyll binding protein. The aim of this contribution is the spectroscopic charact erization of such complex designated CP 34* and isolated from the iron-stre ssed cells of the thermophilic cyanobacterium Synechococcus elongatus. The study is focused on the ultrafast primary photosynthetic processes assessed by means of low temperature and hole-burning spectroscopy. These technique s allowed us to obtain the exciton relaxation times in the complex and to d etermine the strength of pigment-protein interaction. Also the site distrib ution function acquired from the burned holes depth is shown. (C) 2000 Else vier Science B.V. All rights reserved.