Organization of the photosystem II centers and their associated antennae in the thylakoid membranes: a comparative ultrastructural, biochemical, and biophysical study of Chlamydomonas wild type and mutants lacking in photosystem II reaction centers.

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Abstract
The ultrastructure of thylakoid membranes that lacked either some or all of their photosystem [PS] II centers in the F34SU3 and F34 mutants of C. reinhardtii was investigated. There are no particles of the 160-.ANG. size class on the EF [exoplasmic face] of the thylakoids in the absence of PSII centers (as in F34), the F34SU3 contains 50% of the wild-type number of PSII centers and EF particles. The density of the particles on the PF [protoplasmic face] of the thylakoids is higher in the mutants than in the wild type. The fluorescence analysis shows that the organization of the pigments is the same regardless of whether 50% of the PSII centers are temporarily inactivated (by preilluminating the wild type) or are actually missing from the thylakoid membrane (F34SU3). Apparently, each 160-.ANG. EF particle has only one PSII center surrounded by light-harvesting complexes and part of the PSII antenna is associated with 80-.ANG. PF particles in both of the mutants and the wild type.