Effects of chaotropic electrolytes on the structure and electronic excitation coupling of glutaraldehyde- and diimido ester-cross-linked phycobilisomes

Structure and Function of Light‐harvesting Complexes and Their Polypeptides

“…Polypeptide crosslinking in the phycobilisome (Nostoc in situ, in vitro) with glutaraldehyde stabilizes the phycobilisomes against dissociating KN03 aAPB and KSCN solutions (chaotropic effect, inter-and intra-hexamer crosslinking). Crosslinking with dimethyl-suberimidate and dissociation in these chaotropic electrolytes produces monomers (intramonomer crosslinks) (Papageorgiou and Lagoyanni, 1983).…”

Immobilization of photosynthetically active cyanobacteria in glutaraldehyde-crosslinked albumin matrix

“…One of the most labile components of the photosynthetic apparatus of cyanobacteria is the extrathylakoid light harvesting system of phycobilisomes. The spectral properties of phycobilisomes are very sensitive to chemical and thermal denaturation, but covalent interpolypeptide crosslinking has been shown to stabilize their structure (Papageorgiou and Sofrova 1983;Papageorgiou and Lagoyanni 1983). Figure 1 displays absorption spectra of free (A) and of matrix-immobilized (B) Anacystis after a 10 rain exposure to the indicated temperatures.…”

“…On the other hand, glutaraldehyde does enter into the cytoplasm, as is made evident by the stabilization of phycobiliproteins against thermal denaturation after immobilization of the cyanobacteria. We may attribute the phycobiliprotein stabilization to intra-and interpolypeptide crosslinking (Papageorgiou and Sofrova 1983;Papageorgiou and Lagoyanni 1983). Preservation of the native state of phycobiliproteins is very important for efficient photosynthe-sis, since they are the main light harvesting pigments of these organisms.…”