Structure of the Chlamydomonas reinhardtii cabII-1 gene encoding a chlorophyll-a/b-binding protein

Imbault, P.; Wittemer, C.; Johanningmeier, Udo; Jacobs, Jerry D.; Howell, Stephen H.

doi:10.1016/0378-1119(88)90504-5

Cited by 81 publications

(53 citation statements)

References 28 publications

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“…Four of the contigs were identical to the previously described Chlamydomonas Lhc genes Cab II-1, Lhcb2, Lhcb3, and CabII-2 (Imbault et al, 1988;Somanchi et al, 1998; J.H. Mussgnug and O. Kruse, unpublished data).…”

Section: Ten Genes Encode Major Lhcii Polypeptides In Chlamydomonassupporting

confidence: 56%

A Major Light-Harvesting Polypeptide of Photosystem II Functions in Thermal Dissipation[W]

2002

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Under high-light conditions, photoprotective mechanisms minimize the damaging effects of excess light. A primary photoprotective mechanism is thermal dissipation of excess excitation energy within the light-harvesting complex of photosystem II (LHCII). Although roles for both carotenoids and specific polypeptides in thermal dissipation have been reported, neither the site nor the mechanism of this process has been defined precisely. Here, we describe the physiological and molecular characteristics of the Chlamydomonas reinhardtii npq5 mutant, a strain that exhibits little thermal dissipation. This strain is normal for state transition, high light-induced violaxanthin deepoxidation, and low light growth, but it is more sensitive to photoinhibition than the wild type. Furthermore, both pigment data and measurements of photosynthesis suggest that the photosystem II antenna in the npq5 mutant has one-third fewer light-harvesting trimers than do wild-type cells. The npq5 mutant is null for a gene designated Lhcbm1 , which encodes a light-harvesting polypeptide present in the trimers of the photosystem II antennae. Based on sequence data, the Lhcbm1 gene is 1 of 10 genes that encode the major LHCII polypeptides in Chlamydomonas. Amino acid alignments demonstrate that these predicted polypeptides display a high degree of sequence identity but maintain specific differences in their N-terminal regions. Both physiological and molecular characterization of the npq5 mutant suggest that most thermal dissipation within LHCII of Chlamydomonas is dependent on the peripherally associated trimeric LHC polypeptides.

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Section: Ten Genes Encode Major Lhcii Polypeptides In Chlamydomonassupporting

confidence: 56%

A Major Light-Harvesting Polypeptide of Photosystem II Functions in Thermal Dissipation[W]

2002

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“…For the putative lhca10 gene product, no 100% matching sequences could be found in the genomic database. Since lhcbm6 (formerly lhcb1) (23), which was the first LHC-encoding cDNA that was cloned, is not completely represented, further assemblies of the genomic data are needed before final conclusions can be drawn. Therefore, the putative lhca10 gene product could represent a 10th Lhca subunit.…”

Section: Discussionmentioning

confidence: 99%

“…Reanalysis of these proteins by BLAST similarity searches showed that p18 was most similar to Lhca5 from Arabidopsis (24) ( Table 3). When we investigated the novel precursor proteins [11,23]), Lhcbm7 (AF479779 [11]), Lhcbm8 (AF330793. [38]), Lhcbm9 (AF479778 [11]), Lhcbm10 (AF479777 [11]), Lhcb5 (CP26 and AB050007 [32] p15, p19, and p22.2 by BLAST similarity searches, it appeared that p15 was highly similar to Lhca5, while p19 and p22.2 were most similar to Lhca2 from Arabidopsis (24) ( Table 3).…”

Section: Ms (Lc-ms and Lc-ms-ms)mentioning

confidence: 99%

Proteomics of Chlamydomonas reinhardtii Light-Harvesting Proteins

et al. 2003

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With the recent development of techniques for analyzing transmembrane thylakoid proteins by two-dimensional gel electrophoresis, systematic approaches for proteomic analyses of membrane proteins became feasible. In this study, we established detailed two-dimensional protein maps of Chlamydomonas reinhardtii light-harvesting proteins (Lhca and Lhcb) by extensive tandem mass spectrometric analysis. We predicted eight distinct Lhcb proteins. Although the major Lhcb proteins were highly similar, we identified peptides which were unique for specific lhcbm gene products. Interestingly, lhcbm6 gene products were resolved as multiple spots with different masses and isoelectric points. Gene tagging experiments confirmed the presence of differentially N-terminally processed Lhcbm6 proteins. The mass spectrometric data also revealed differentially N-terminally processed forms of Lhcbm3 and phosphorylation of a threonine residue in the N terminus. The N-terminal processing of Lhcbm3 leads to the removal of the phosphorylation site, indicating a potential novel regulatory mechanism. At least nine different lhca-related gene products were predicted by comparison of the mass spectrometric data against Chlamydomonas expressed sequence tag and genomic databases, demonstrating the extensive variability of the C. reinhardtii Lhca antenna system. Out of these nine, three were identified for the first time at the protein level. This proteomic study demonstrates the complexity of the light-harvesting proteins at the protein level in C. reinhardtii and will be an important basis of future functional studies addressing this diversity.In all eukaryotic oxygenic photosynthetic organisms, lightharvesting chlorophyll a-or b-binding proteins (LHC proteins) function in the collection and transfer of light energy to the reaction centers of photosystem II (PSII) (Lhcb proteins) and photosystem I (PSI) (Lhca proteins). Additionally these proteins are also involved in light dissipation and energy quenching. Therefore, light-harvesting proteins are important components of the photosynthetic machinery that optimize photosynthetic function and minimize photooxidative damage in response to light quantity and quality. It has been known for several years that light-harvesting proteins are products of many genes. This concept is illustrated by a recent analysis of the Arabidopsis genome which revealed that the lhc gene family is composed of more than 20 genes (24). Besides the large number of lhc gene products, posttranslational modifications, such as phophorylation, contribute to even more complexity at the protein level (31, 45). Phosphorylation of the major Lhcb proteins of PSII is important in the process of state transitions. This process leads to a redistribution of excitation energy between PSII and PSI by reorganization of the antennae and thereby regulates energy flow between the photosystems. The importance of phosphorylation for state transitions is shown by the phenotype of the Chlamydomonas reinhardtii Stt7 mutant. This mutant is markedly ...

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“…larger polypeptide corresponds to LHCP II type I of C. reinhardtii (51) and that the smaller one contains the N-terminal sequence IEXYGPDRPKFLGPFR. Comparison with other LHCP II sequences shows that it corresponds to a LHCP II type II protein (52), which has not yet been identified in C. reinhardtii.…”

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confidence: 99%

Limitation in Electron Transfer in Photosystem I Donor Side Mutants of Chlamydomonas reinhardtii

Hippler¹,

Biehler²,

Krieger‐Liszkay³

et al. 2000

Journal of Biological Chemistry

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Strains of Chlamydomonas reinhardtii lacking thePsaF gene or containing the mutation K23Q within the N-terminal part of PsaF are sensitive to high light (>400 E m ؊2 s ؊1 ) under aerobic conditions. In vitro experiments indicate that the sensitivity to high light of the isolated photosystem I (PSI) complex from wild type and from PsaF mutants is similar. In vivo measurements of photochemical quenching and oxygen evolution show that impairment of the donor side of PSI in the PsaF mutants leads to a diminished linear electron transfer and/or a decrease of photosystem II (PSII) activity in high light. Thermoluminescence measurements indicate that the PSII reaction center is directly affected under photo-oxidative stress when the rate of electron transfer becomes limiting in the PsaF-deficient strain and in the PsaF mutant K23Q. We have isolated a high light-resistant PsaF-deficient suppressor strain that has a high chlorophyll a/b ratio and is affected in the assembly of light-harvesting complex. These results indicate that under high light a functionally intact donor side of PSI is essential for protection of C. reinhardtii against photo-oxidative damage when the photosystems are properly connected to their light-harvesting antennae.Photosynthesis is driven by light. Photons are absorbed by pigments of the light harvesting chlorophyll-carotenoid-protein complexes that are associated with the membrane embedded photosynthetic reaction centers. Excitation energy can be transferred to the reaction centers where it induces charge separation across the membrane. This leads to a series of electron transfer reactions resulting in oxidation of water and the production of chemical energy in the form of ATP and NADPH, which are used for CO 2 fixation. If the absorption of light exceeds the capacity of photosynthetic energy consumption, over-reduction of the electron transport carriers and increase of the lifetime of excited states in the light-harvestingantennae occur. Over-reduction of the electron carriers can lead to photo-oxidative damage by reactive oxygen species. O 2 can be directly reduced by PSI 1 (1) generating superoxide anion radical (O 2 . ) and other reactive oxygen species. Increase in the lifetime of excited singlet chlorophyll increases the probability of triplet chlorophyll formation, which can react with O 2 to produce 1 O 2 (2, 3). Reactive oxygen species cause photo-oxidative damage, especially to PSII, which is considered to be the primary target for photoinhibition (4 -6). Thus, mechanisms that balance energy input through photochemistry with energy consumption through CO 2 assimilation and other metabolic pathways are essential for plant survival.Mechanisms that balance energy input and consumption can be divided into short and long term responses. Short term responses include nonphotochemical dissipation of excess energy (7, 8) and reduction of energy transfer to PSII through state transition, a process that leads to a redistribution of excitation energy to PSI by a reorganization of the antennae (...

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Structure of the Chlamydomonas reinhardtii cabII-1 gene encoding a chlorophyll-a/b-binding protein

Cited by 81 publications

References 28 publications

A Major Light-Harvesting Polypeptide of Photosystem II Functions in Thermal Dissipation[W]

A Major Light-Harvesting Polypeptide of Photosystem II Functions in Thermal Dissipation[W]

Proteomics of Chlamydomonas reinhardtii Light-Harvesting Proteins

Limitation in Electron Transfer in Photosystem I Donor Side Mutants of Chlamydomonas reinhardtii

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