Phycobilisomes supply excitations to both photosystems in a megacomplex in cyanobacteria.

ABSTRACT: In photosynthetic organisms, photons are captured by light-harvesting antenna complexes, and energy is transferred to reaction centers where photochemical reactions take place. We describe here the isolation and characterization of a fully functional megacomplex composed of a phycobilisome antenna complex and photosystems I and II from the cyanobacterium Synechocystis PCC 6803. A combination of in vivo protein cross-linking, mass spectrometry, and time-resolved spectroscopy indicates that the megacomplex is organized to facilitate energy transfer but not intercomplex electron transfer, which requires diffusible intermediates and the cytochrome b6f complex. The organization provides a basis for understanding how phycobilisomes transfer excitation energy to reaction centers and how the energ

SUBMITTER: Liu H 

PROVIDER: S-EPMC3947847 | biostudies-literature | 2013 Nov

REPOSITORIES: biostudies-literature