Ca2+-binding reduces conformational flexibility of RC–LH1 core complex from thermophile Thermochromatium tepidum

Jakob-Grun, Selma; Radeck, Jara; Braun, Paula

doi:10.1007/s11120-012-9727-8

Cited by 16 publications

(12 citation statements)

References 48 publications

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“…tepidum , as insertion of an alanine into this site has been shown to disrupt the Ca 2+ binding, leading to a blue shift of the LH1 Qy absorption peak . This is in accordance with the result of recent spectroscopy measurements showing that the binding of Ca 2+ reduces the conformational flexibility and contribute to the red shit of the LH1 Qy transition as well as the thermostability of LH1‐RC complex.…”

Section: Ca2+‐binding Sitessupporting

confidence: 88%

Novel features of LH1‐RC from Thermochromatium tepidum revealed from its atomic resolution structure

Suga

Wang-Otomo

et al. 2018

The FEBS Journal

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Light‐harvesting‐1 (LH1)‐reaction center (RC) super‐complex is a membrane protein–pigment complex existing in purple photosynthetic bacteria, where LH1 absorbs light energy and transfers them rapidly and efficiently to RC to initiate the charge separation and electron transfer reactions. The structure of LH1‐RC has been reported at relatively low resolutions from several different species of bacteria previously, but was solved at an atomic resolution recently from a thermophilic photosynthetic bacterium Thermochromatium tepidum. This high‐resolution structure revealed the detailed organization of the super‐complex including a number of unique features that are important for its functioning, such as a more intact RC structure, transporting routes for quinones to replace the bound QB as well as for the in‐and‐out of the closed LH1 ring, detailed coordinating environment of the Ca2+ ions in LH1 important for the remarkable red shift of the absorption spectrum, as well as for the enhanced thermostability. These results thus greatly advance our understanding on the mechanisms of energy transfer, quinone exchange, the red shift in the LH1‐Qy transition and the enhanced thermal stability, in this super‐complex.

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Section: Ca2+‐binding Sitessupporting

confidence: 88%

Novel features of LH1‐RC from Thermochromatium tepidum revealed from its atomic resolution structure

Suga

Wang-Otomo

et al. 2018

The FEBS Journal

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“…Much of the insight gained from the thoroughly investigated Tch. tepidum LH1-RC 9 – 11 , 14 , 15 , 18 , 20 , 28 – 30 has paved the way for understanding the structural basis of the spectroscopic behavior of the Trv . strain 970 LH1-RC because the Ca 2+ -binding sites are similar in the two complexes.…”

Section: Discussionmentioning

confidence: 99%

“…However, hydrogen bonding with pigments can explain only part of the extra redshifts of the LH1-Q y transition as seen in the Tch. tepidum LH1-RC 19 because structural disorder and the dynamic property of the BChl a -binding environment also need to be taken into account 9 , 14 , 15 , 28 , 29 , 36 . This is supported by the fact that the full C-terminal domains of all LH1 α-polypeptides can be traced from the current density map (2.82 Å resolution) observed for the Trv .…”

Section: Discussionmentioning

confidence: 99%

Cryo-EM structure of a Ca2+-bound photosynthetic LH1-RC complex containing multiple αβ-polypeptides

et al. 2020

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The light-harvesting-reaction center complex (LH1-RC) from the purple phototrophic bacterium Thiorhodovibrio strain 970 exhibits an LH1 absorption maximum at 960 nm, the most red-shifted absorption for any bacteriochlorophyll (BChl) a-containing species. Here we present a cryo-EM structure of the strain 970 LH1-RC complex at 2.82 Å resolution. The LH1 forms a closed ring structure composed of sixteen pairs of the αβ-polypeptides. Sixteen Ca ions are present in the LH1 C-terminal domain and are coordinated by residues from the αβ-polypeptides that are hydrogen-bonded to BChl a. The Ca2+-facilitated hydrogen-bonding network forms the structural basis of the unusual LH1 redshift. The structure also revealed the arrangement of multiple forms of α- and β-polypeptides in an individual LH1 ring. Such organization indicates a mechanism of interplay between the expression and assembly of the LH1 complex that is regulated through interactions with the RC subunits inside.

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“…ATR–FTIR spectra (3,050–900 cm −1 ) were taken with 4 cm −1 resolution and a sampling time of 32 scans [39]. Frozen pollen samples were placed onto the crystal cell and gently compressed during measurement.…”

Section: Methodsmentioning

confidence: 99%

Molecular and Immunological Characterization of Ragweed (Ambrosia artemisiifolia L.) Pollen after Exposure of the Plants to Elevated Ozone over a Whole Growing Season

et al. 2013

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Climate change and air pollution, including ozone is known to affect plants and might also influence the ragweed pollen, known to carry strong allergens. We compared the transcriptome of ragweed pollen produced under ambient and elevated ozone by 454-sequencing. An enzyme-linked immunosorbent assay (ELISA) was carried out for the major ragweed allergen Amb a 1. Pollen surface was examined by scanning electron microscopy and attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR), and phenolics were analysed by high-performance liquid chromatography. Elevated ozone had no influence on the pollen size, shape, surface structure or amount of phenolics. ATR-FTIR indicated increased pectin-like material in the exine. Transcriptomic analyses showed changes in expressed-sequence tags (ESTs), including allergens. However, ELISA indicated no significantly increased amounts of Amb a 1 under elevated ozone concentrations. The data highlight a direct influence of ozone on the exine components and transcript level of allergens. As the total protein amount of Amb a 1 was not altered, a direct correlation to an increased risk to human health could not be derived. Additional, the 454-sequencing contributes to the identification of stress-related transcripts in mature pollen that could be grouped into distinct gene ontology terms.

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Ca2+-binding reduces conformational flexibility of RC–LH1 core complex from thermophile Thermochromatium tepidum

Cited by 16 publications

References 48 publications

Novel features of LH1‐RC from Thermochromatium tepidum revealed from its atomic resolution structure

Novel features of LH1‐RC from Thermochromatium tepidum revealed from its atomic resolution structure

Cryo-EM structure of a Ca2+-bound photosynthetic LH1-RC complex containing multiple αβ-polypeptides

Molecular and Immunological Characterization of Ragweed (Ambrosia artemisiifolia L.) Pollen after Exposure of the Plants to Elevated Ozone over a Whole Growing Season

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