PHYCOBILISOME CORE MUTANTS OF SYNECHOCYSTIS PCC-6803

Mutant strains of the cyanobacterium Synechocystis 6803 were constructed in which either the apcABC operon, encoding core subunits allophycocyanin alpha and beta and a small linker L(C)(8), or the apcE gene encoding the phycobilisome core-membrane linker was deleted, Phycobilisome assembly and energy transfer were studied in these mutants using both SDS gel analysis of phycobiliprotein complexes and low temperature fluorescence spectroscopy. Both mutants assembled phycocyanin rods but neither assembled a core complex. Although the mutants have no functional phycobilisomes, they grow photoautotrophically. No energy transfer between the remaining soluble phycobiliproteins and the photosystems was observed.