Section 21
Chapter 20,712

Characterization of new strains of nonphotosynthetic mutants of Chlamydomonas reinhardtii. 3. Photosystem 2-related thylakoid proteins in five mutants and double mutants

Maroc, J.; Guyon, D.; Garnier, J.

Plant and Cell Physiology 247: 1217-1230


ISSN/ISBN: 0032-0781
Accession: 020711865

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PS photosystem II-enriched particles of the wild type, of 3 mutants and of 2 double mutants of C. reinhardtii were analyzed by lithium dodecylsulfate polyacrylamide gel electrophoresis at 4.degree. C. The mutant Pg 27 was devoid of light-harvesting Chl chlorophyl -protein complex (CP) CP II, but had normal cytochrome b-559 and displayed all wild type photochemical activities. The mutant Fl 50 lacked a pool of crytochrome b-559 photooxidizable at 77.degree. K but was able to photooxidize a 2nd pool at 293.degree. K in the presence of FCCP carbonylcyanide-p-trifluoromethoxyphenylhydrazone ; it showed some weak PS II activity. The mutant Fl 39 lacke both these cytochrome b-559 pools and did not display any PS II activity. The double mutants Fl 39 Pg 28 and Fl 50 Pg 27 had defects similar to those of their respective parents Fl 39 or Fl 50 but, in addition, they were devoid of Chl b and of CP II. In these 4 mutants having impaired PS II function, 5 proteins of MW = 50,000, 47,000, 33,000, 27,000 ad 19,000 were totally (Fl 39, Fl 39 Pg 28) or partly (Fl 50, Fl 50 Pg 27) missing. The first 2 of these proteins corresponded to the apoproteins of CP III and IV. A strong correlation between these 5 proteins, cytochrome b-559 and PS II primary photochemistry was apparent. In mutation and cross experiments, these 5 PS II-associated proteins and cytochrome b-559 appeared to be linked characters controlled by nuclear gene(s), but they behaved independently of CP II.

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