Cryo-EM structure of the of Reaction center light harvesting

complex 1 (RC-LH1) from photosynthetic bacterium

Blastochlorisviridis RC-LH1 complex at 2.9 ?

Dr. PuQian（錢樸）

Department of Molecular Biology and Biotechnology, The University of Sheffield,

  Sheffield S10 2TN, UK.報告人：

Abstract

pore and eventual diffusion to the cytochromebc1 complex. The reaction centre light-harvesting 1 (RC-LH1) complex is the core functional component of bacterial photosynthesis. A 2.9 ? resolution cryo-EM structure of the bacteriochlorophyllb-based RC-LH1 from Blastochlorisviridisreveals the structural basis for absorption of infrared light, and the molecular mechanism of quinone migration across the LH1 complex. The novel triple ring LH1 complex comprises a circular array of 17 β-polypeptides sandwiched between 17 α- and 16 γ-polypeptides. Tight packing of the γ-apoproteins between βs collectively interlocks and stabilizes the LH1 structure which, together with the short Mg-Mg distances of BChlb pairs, contributes to the large red-shift of bacteriochlorophyllb absorption. The ‘missing’ 17th γ polypeptide creates a pore in the LH1 ring, and an adjacent binding pocket provides a folding template for a novel quinone, QP, which adopts a compact, export-ready conformation prior to passage through the

個人簡介：

PuQian is a Professor (part-time), School of Life Science, Suzhou University and Research associate of Department of Molecular Biology & Biotechnology, The University of Sheffield, UK. His main research work are High resolution structures of light harvesting core complexes from photosynthetic bacteria using cryo-EM. His expertise include protein purification, 2D/3D crystallizations, EM measurement, data processing and presentation. 2D electron crystallography, X-ray crystallography and cryo-EM single particle analysis have been employed for structure determination of membrane proteins. During the last decade, he published a series of papers on the structure determination of RC-LH1 core  complexes from photosynthetic bacteria.  Recently, a 2.9 ? resolution cryo-EM structure of the core complexes from Blastochlorisviridiswild was accepted by Nature as an article. This structure revealed a new architecture of the RC-LH1 core complex from photosynthetic bacteria, explained its large red-shift absorption of bacteriochlorophyll b in the complex and mechanism of quinone / quinol