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Immunogold localization of photosystem I and photosystem II light‐harvesting complexes in cryptomonad thylakoids
Author(s) -
Lichtle´ Christiane,
McKay R Michael L,
Gibbs Sarah P
Publication year - 1992
Publication title -
biology of the cell
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.543
H-Index - 85
eISSN - 1768-322X
pISSN - 0248-4900
DOI - 10.1016/0248-4900(92)90024-u
Subject(s) - thylakoid , biology , photosystem ii , immunogold labelling , photosystem , light harvesting complexes of green plants , photosystem i , cytochrome b6f complex , biophysics , immunoelectron microscopy , phycobilisome , chloroplast , botany , biochemistry , photosynthesis , cyanobacteria , ultrastructure , immunohistochemistry , gene , immunology , genetics , bacteria
Summary— The molecular organization of the thylakoids of Cryptomonas rufescens was studied by immunoelectron microscopy employing antibodies against photosystem (PS)‐I and two PS‐II antenna proteins. The PS‐I complex and the 19‐kDa chlorophyll a/c light‐harvesting (LH) protein are both localized along the length of the thylakoid membranes. The external membranes of the paired thylakoids are enriched in PS‐I whereas the chlorophyll a/c LH protein is more concentrated in the internal or appressed membranes. However, unlike the situation in higher plants and Chlamydomonas , there is not a marked asymmetry in the concentration of PS‐I and chorophyll a/c LH protein in the two types of membranes. Double labelling studies of sections and isolated PE‐PS‐II particles with anti‐phycoerythrin and anti‐LH confirmed that phycoerythrin is localized in the thylakoid lumen and that this pigment exists in two forms, a fraction closely associated with the thylakoid membranes and another fraction free in the lumen. These results confirm the uniqueness of cryptomonad thylakoids.