Ultrastructure and light adaptation of phycobilisome mutants of Synechocystis PCC 6803

Abstract

We have performed functional and ultrastructural characterization of Synechocystis PCC 6803 wild type and of two mutants, the first one (PMB11) lacking phycocyanin and still possessing the core of the phycobilisome and the second one (PΔE) lacking phycocyanin and Lcm (the core-membrane linker) and totally devoid of assembled phycobilisome structure. In the three strains, the state 1-state 2 transition occurred and was accompanied by ultrastructural changes. In state 1, an increased percentage of PS II-associated EF particles were aligned in rows compared to state 2 where more EF particles were randomly distributed in the membrane. A spill-over model is suggested by our ultrastructural and spectrophotometric results.© 1997 Elsevier Science B.V. All rights reserved.