Fykobilisomit

Fykobilisomit are large protein complexes found in cyanobacteria, red algae, and glaucophytes that act as light-harvesting antennae. They are crucial for photosynthesis, particularly in absorbing wavelengths of light that chlorophyll cannot efficiently capture. These structures are composed of proteins called phycobiliproteins, which are covalently linked to open-chain tetrapyrrole pigments called phycobilins.

The arrangement of fykobilisomit is highly ordered, often appearing as rod-like or hemi-elliptical structures attached to the outer surface of the thylakoid membranes within the chloroplast. This precise organization allows for efficient transfer of excitation energy from the phycobilins to the reaction centers of photosystems. The specific composition and arrangement of fykobilisomit can vary between different organisms, contributing to their ability to adapt to diverse light environments.

The phycobilins within fykobilisomit absorb light and then transfer the energy via fluorescence resonance energy transfer (FRET) through a series of phycobiliproteins to a terminal acceptor, usually a phycobiliprotein associated with photosystem II. This light-harvesting function is essential for maximizing photosynthetic efficiency, especially in low-light conditions or when certain wavelengths are dominant. Research into fykobilisomit continues to explore their structure, function, and potential applications in areas like bioenergy and molecular imaging.