Light-harvesting chlorophyll a/b-protein

Simidjiev, L, Barzda, V., Mustardy, L., and Garab, G. 1997. Isolation of lamellar aggregates of the light-harvesting chlorophyll a/b protein complex of photosystem II with long-range chiral order and structural flexibility. Anal. Biochem. 250 169-75. 

The literature search was now expanded and yielded the conclusion that another possible and more widespread precursor is the light-harvesting chlorophyll a/b-protein (LHCP), which is present in almost all photosynthetically grown higher plants and green algae (ref. 373-375). It is by far the major pigment-protein in these plants and accounts for 40-60% of the total chlorophyll (ref. 373,374). 

Table 5.2 lists the amino acid molar ratios determined for LHCP from several plant sources, and compares these results with the mean values obtained for the main glycopeptide subfraction (peak I in Table 5.1) from microbubble surfactant. It can be seen from Table 5.2 that the amino acid composition of LHCP clearly resembles that of the main glycopeptide subfraction. Specifically, in both cases nonpolar residues represent a majority and near constant fraction (i.e., 59-62%) of the amino acid composition, with the relative amounts of such residues in practically all individual cases listed following the pattern glycine > leucine, alanine, valine, proline > isoleucine, phenylalanine > methionine, tryptophan (Table 5.2). Accordingly, the glycopeptide fraction of microbubble surfactant may represent a degradation product of the light-harvesting chlorophyll a/b-protein, which is well known (ref. 373-375) to be extremely widely distributed in terrestrial, freshwater, and salt-water environments (cf. ref. 379).

I.J. Ryrie and N. Fuad, Membrane adhesion in reconstituted proteoliposomes containing the light-harvesting chlorophyll a/b-protein complex the role of charged surface groups, Arch. Biochem. Biophys. 214 (1982) 475-488. 

K.S. Kan and J.P. Thomber, Hie light-harvesting chlorophyll a/b-protein complex of Chlamydomonas reinhardii, Plant Physiol. 57 (1976)47-52. 

Sukenik A, Bennett J, Falkowski PG. (1988). Changes in the abundance of individual apoproteins of light-harvesting chlorophyll a/b-protein complexes of photosystem I and II with growth irradiance in the marine chlorophyte Dunaliella tertiolecta. Biochim. Biophys. Acta 932, 206-215. 

Fig. 2. (A) A hydropathy plot of the amino-acid sequence of pea LHC II. (B) A sketch of the amino-acid sequence of the LHC II from Lemna gibba (an aquatic monocot). (A) from R Bargi, F Suter and H Zuber (1987) Arrangement of the light-harvesting Chlorophyll a/b protein complex in the thylakoid membrane. Biochim Biophys Acta 890 348 (B) from GA Karlin-Neumann, BD Kohorn, JP Thornber and EM Tobin (1985) A chlorophyll a/b-protein encoded by a gene containing an Intron with characteristics of a (rans-posable element. J Mol AppI Genet. 3 58.

JE Mullet, JJ Burke and CJ Arntzen (1980) Chlorophyll proteins of photosystem I. Plant Physiol 65 814-822 E Lam, W Ortiz, S Mayfield and R Malkin (1984) Isolation and characterization of a light-harvesting chlorophyll a/b protein complex associated with photosystem I. Plant Physiol 74 650-655 E Lam, W Ortiz and R Malkin (1984) Chlorophyll alb proteins of photosystem I. FEBS Lett 168 10-14 H Michel (1982) 3-dimensional crystals of a membrane protein complex. The photosynthetic reaction center from Rhodopseudomonas viridis. J Mol Biol 158 567-572... 

Siefermann-Harms D (1990c) Protective function of the apoprotein of the light-harvesting chlorophyll-a/b-protein complex in pigment photo-oxidation. J Photochem Photobiol B Biol 4 283-295... 

STRUCTURE OF THE LIGHT-HARVESTING CHLOROPHYLL a/b PROTEIN COMPLEX BY HIGH-RESOLUTION ELECTRON CRYSTALLOGRAPHY... 

THE MAJOR LIGHT-HARVESTING CHLOROPHYLL a/b PROTEIN (LHC lib) THE SMALLEST SUBUNIT IS A NOVEL CAB GENE PRODUCT... 

The procedure for the isolation of chloroplasts from cell wall mutants of Chlamydomonas yields relatively pure, active chloroplasts. These chloroplast were photosynthetically active (3) and synthesized proteins in organello (4). They also imported, processed and assembled in vitro synthesized precursors for the small subunit of ribulose bisphosphate carboxylase and for the light harvesting chlorophyll a/b proteins (5, 6, 7). 

Structure of the Light-Harvesting Chlorophyll a/b Protein Complex by High-Resolution... 

Dubertret G, Mirshahi A, Mirshahi M, Gerard-Hime C, and Tremolieres A. Evidence from in vivo manipulations of lipid composition in mutants that the t -trans- hexadecenoic acid-containing phosphatidylglycerol is involved in the biogenesis of the light harvesting chlorophyll a/b-protein complex of Chlamydomonas reinhardtii. Eur J Biochem. 1994 226 473-482. 

Tremolieres A, Dubacq JP, Ambard-Bretteville F, and Remy R. Lipid composition of chlorophyll-protein complexes. Specific enrichment in trans-hexadecenoic acid of an oligomeric form of light harvesting chlorophyll a/b protein. FEBS Lett. 1981 130 27-31. 

H.Y. (1982) Reconstitution by monogalactosyldiacylglycerol of energy transfer from light-harvesting chlorophyll a/b-protein complex to the photosystems in Triton X-100-solubilized thylakoids. FEES Lett. 149 191-196. 

Although extensive research work over the past 17 years has provided a large body of informations, the detailed composition of chlorophyll-protein bands is still subject to many uncertainties. This mainly concerns the major band previously termed complex II and later on light-harvesting chlorophyll a/b-protein (Thornber, Highkin 1974) The following experiments were performed under the aspect of its further characterization. 

Lotshaw, W.T., Alberte, R.S., and Fleming, G.R. (1982). Low-intensity subnanosecond fluorescence study of the light-harvesting chlorophyll a/b protein, Biochim. Biophys. Acta, 682, 75-85. 

Kiihlbrandt W, Thaler T and Wehrli E (1983) The structure of membrane crystals of the light-harvesting chlorophyll a/b-protein complex, J. Cell Biol. 96, 1414-1424. 

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