Although the 32 kOa-polypeptide (0-1) is a minor component of thyla koids in algae and higher plants. much attention has been focused on it. It was shown to be the binding site for herbicides (Pfister et al. 1981). the rapidly synthesized polypeptide of thylakoid membranes (Edelman and Reisfeld 1978; Owens et al. 1982) and to participate in Qa binding (Arntzen et al. 1984; Kyle et al. 1984; Ohad et al. 1984). Measurements of the stoichiometry of the various PS II polypeptides in C. reinhardii showed that thylakoids contain about one herbicide binding polypeptide per one PS II unit and the accelerated light sti mulated turnover of the 32 kOa-polypeptide was postulated to be the consequence of its function in quinone reduction. Based on comparison of amino acid sequence and hydropathy profile homologies of 0-1 and 0-2 with the subunits of the bacterial photosystem. recently a model was presented. in which the reaction center of photosystem II in algae and higher plants is formed by the polypeptides 0-1 and 0-2 (Trebst 1986). The structural gene of the 32 kOa-polypeptide (psbA) has been mapped on the chloroplast DNA and cloned from various plant species (for a review: Kyle 1985). The polypeptide is synthesized as a precursor on ribosomes bound to unstacked lamellae and there proc essed to its mature form (Edelman and Reisfeld 1978; Herrin and Michaels 1985). In C. reinhardii the 0-1 polypeptide is phosphorylat ed by a light-activated membrane bound kinase.

Inhalt
Interaction of Circadian Oscillators and the Cell Developmental Cycle in Euglena.- Control Points in the Chlamydomonas Cell Cycle.- Two Possibilities for Time Measurement in Synchronous ChlorellaCircadian Rhythm and Timing.- Diatom Mitosis: Implications of a Model System.- Wall Morphogenesis in Centric Diatoms.- Cell Elongation in the Red Alga Griffithsia: Control by Light, Ions, and an Endogenous Glycoprotein Hormone.- Molecular Signals During Sexual Induction of Volvox carteri.- Pheromone-Inducible Glycoproteins of the Extracellular Matrix of Volvox and Their Possible Role in Sexual Induction.- Environmental and Pheromonal Control of Sexual Reproduction in Laminaria (Phaeophyceae).- Action of Cell Wall Autolysins in Asexual Reproduction of Filamentous Green Algae: Evidence and Species Specificity.- Sexual Agglutination in Chlamydomonas eugametos.- Molecular Recognition Properties of Chlamydomonas HRGP's.- Maturation of a Flagellum/Basal Body Requires More Than One Cell Cycle in Algal Flagellates: Studies on Nephroselmis olivacea (Prasinophyceae).- Protein Synthesis in Chloroplasts.- Comparison of Envelope Membranes from Higher Plants and Algae Plastids and of Outer Membranes from Cyanobacteria (Blue-Green Algae).- Regulation of Chloroplast Differentiation: Cooperation Between Light-Induced Processes and Internal Adaptation.- Interaction of Nuclear and Chloroplast Mutations in Biogenesis of Chloroplast Ribosomes in Chlamydomonas.- Evidence for Multiple Functions of the Intrinsic, 3234 kDa Chloroplast Membrane Polypeptide of Scenedesmus in Photosystem II Reactions.- Life Cycle of the 32 kDa-Protein of Chlamydomonas Chloroplasts.- Two Different Forms of LHC in the Green Alga Chlamydobotrys stellata.- Taxonomic Index.