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

被引：0

作者：

Kazutoshi Tani

Ryo Kanno

Yuki Makino

Malgorzata Hall

Mizuki Takenouchi

Michie Imanishi

Long-Jiang Yu

Jörg Overmann

Michael T. Madigan

Yukihiro Kimura

Akira Mizoguchi

Bruno M. Humbel

Zheng-Yu Wang-Otomo

机构：

[1] Mie University,Graduate School of Medicine

[2] Imaging Section,Department of Agrobioscience

[3] Research Support Division,Faculty of Life Science, Institute of Microbiology

[4] Okinawa Institute of Science and Technology Graduate University (OIST),Department of Microbiology

[5] Faculty of Science,undefined

[6] Ibaraki University,undefined

[7] Graduate School of Agriculture,undefined

[8] Kobe University,undefined

[9] Photosynthesis Research Center,undefined

[10] Key Laboratory of Photobiology,undefined

[11] Institute of Botany,undefined

[12] Chinese Academy of Sciences,undefined

[13] Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures,undefined

[14] Braunschweig University of Technology,undefined

[15] Southern Illinois University,undefined

来源：

Nature Communications | / 11卷

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摘要：

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.

引用

共 123 条

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