Polypeptide Composition of Chloroplast Membranes in Double Mutants of Chlamydomonas reinhardtii Lacking Chlorophyll b and Photosystem II

G. N. Shirshikova,^1,2 R. A. Khatypov,¹ V. G. Ladygin,¹ and V. A. Shuvalov¹

¹Institute of Soil Science and Photosynthesis, Russian Academy of Sciences, Pushchino, Moscow Region, 142292 Russia; E-mail: ladygin@issp.serpukhov.su

²To whom correspondence should be addressed.

Submitted January 20, 1997.

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A wild strain K(+), a single chlorophyll b-deficient mutant strain C-48, and double AC-mutant strains with modified photosystem II were assayed gel-electrophoretically for chlorophyll--protein complexes and polypeptide composition. The first mutation causes a chlorophyll b-deficiency. Light-harvesting chlorophyll a/b--protein complex II is modified and polypeptides 26, 28, and 31 kD are absent in all the mutants studied. In addition, the second mutation of the double mutants AC-121, AC-234, and AC-864 causes the absence of the photosystem II polypeptides incorporated into the reaction center site (D1 and D2 proteins with molecular weights 30 and 32 kD, respectively) and in the water-photooxidizing complex (23 and 34 kD). In addition to these polypeptides, the double mutant AC-184 contains a reduced amount of polypeptides CP43 and CP47 with molecular weights 47 and 51 kD, respectively. Thus, because of the absence of the polypeptides listed above, the double mutants are able to synthesize neither the light-harvesting chlorophyll a/b--protein complex II nor the chlorophyll a--protein complex of photosystem II.

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KEY WORDS: Chlamydomonas reinhardtii Dang., photosystem II (PS II), chlorophyll--protein complexes, polypeptide composition.

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