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do Prado PFV, Ahrens FM, Liebers M, Ditz N, Braun HP, Pfannschmidt T, Hillen HS. Structure of the multi-subunit chloroplast RNA polymerase. Mol Cell 2024; 84:910-925.e5. [PMID: 38428434 DOI: 10.1016/j.molcel.2024.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 01/26/2024] [Accepted: 02/06/2024] [Indexed: 03/03/2024]
Abstract
Chloroplasts contain a dedicated genome that encodes subunits of the photosynthesis machinery. Transcription of photosynthesis genes is predominantly carried out by a plastid-encoded RNA polymerase (PEP), a nearly 1 MDa complex composed of core subunits with homology to eubacterial RNA polymerases (RNAPs) and at least 12 additional chloroplast-specific PEP-associated proteins (PAPs). However, the architecture of this complex and the functions of the PAPs remain unknown. Here, we report the cryo-EM structure of a 19-subunit PEP complex from Sinapis alba (white mustard). The structure reveals that the PEP core resembles prokaryotic and nuclear RNAPs but contains chloroplast-specific features that mediate interactions with the PAPs. The PAPs are unrelated to known transcription factors and arrange around the core in a unique fashion. Their structures suggest potential functions during transcription in the chemical environment of chloroplasts. These results reveal structural insights into chloroplast transcription and provide a framework for understanding photosynthesis gene expression.
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Affiliation(s)
- Paula F V do Prado
- University Medical Center Göttingen, Department of Cellular Biochemistry, Humboldtallee 23, 37073 Göttingen, Germany; Max Planck Institute for Multidisciplinary Sciences, Research Group Structure and Function of Molecular Machines, Am Fassberg 11, 37077 Göttingen, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, 37075 Göttingen, Germany
| | - Frederik M Ahrens
- Institute of Botany, Plant Physiology, Leibniz University Hannover, Herrenhäuser Str. 2, 30419 Hannover, Germany
| | - Monique Liebers
- Institute of Botany, Plant Physiology, Leibniz University Hannover, Herrenhäuser Str. 2, 30419 Hannover, Germany
| | - Noah Ditz
- Institute of Plant Genetics, Plant Molecular Biology and Plant Proteomics, Leibniz University Hannover, Herrenhäuser Str. 2, 30419 Hannover, Germany
| | - Hans-Peter Braun
- Institute of Plant Genetics, Plant Molecular Biology and Plant Proteomics, Leibniz University Hannover, Herrenhäuser Str. 2, 30419 Hannover, Germany
| | - Thomas Pfannschmidt
- Institute of Botany, Plant Physiology, Leibniz University Hannover, Herrenhäuser Str. 2, 30419 Hannover, Germany.
| | - Hauke S Hillen
- University Medical Center Göttingen, Department of Cellular Biochemistry, Humboldtallee 23, 37073 Göttingen, Germany; Max Planck Institute for Multidisciplinary Sciences, Research Group Structure and Function of Molecular Machines, Am Fassberg 11, 37077 Göttingen, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, 37075 Göttingen, Germany; Göttingen Center for Molecular Biosciences (GZMB), Research Group Structure and Function of Molecular Machines, University of Göttingen, 37077 Göttingen, Germany.
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Kalvelage J, Wöhlbrand L, Senkler J, Schumacher J, Ditz N, Bischof K, Winklhofer M, Klingl A, Braun HP, Rabus R. Conspicuous chloroplast with light harvesting-photosystem I/II megacomplex in marine Prorocentrum cordatum. Plant Physiol 2024:kiae052. [PMID: 38330164 DOI: 10.1093/plphys/kiae052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 01/05/2024] [Accepted: 01/06/2024] [Indexed: 02/10/2024]
Abstract
Marine photosynthetic (micro)organisms drive multiple biogeochemical cycles and display a large diversity. Among them, the bloom-forming, free-living dinoflagellate Prorocentrum cordatum CCMP 1329 (formerly P. minimum) stands out with its distinct cell biological features. Here, we obtained insights into the structural properties of the chloroplast and the photosynthetic machinery of P. cordatum using microscopic and proteogenomic approaches. High-resolution FIB/SEM analysis revealed a single large chloroplast (∼40% of total cell volume) with a continuous barrel-like structure, completely lining the inner face of the cell envelope and enclosing a single reticular mitochondrium, the Golgi apparatus, as well as diverse storage inclusions. Enriched thylakoid membrane fractions of P. cordatum were comparatively analyzed with those of the well-studied model-species Arabidopsis (Arabidopsis thaliana) using 2D BN DIGE. Strikingly, P. cordatum possessed a large photosystem-light harvesting megacomplex (>1.5 MDa), which is dominated by photosystems I and II (PSI, PSII), chloroplast complex (CCI), and chlorophylla-b (chla-b) binding light harvesting complex proteins (LhcPs). This finding parallels the absence of grana in its chloroplast and distinguishes from the predominant separation of PSI and PSII complexes in A. thaliana, indicating a different mode of flux balancing. Except for the core elements of the ATP synthase and the cytb6f-complex, the composition of the other complexes (PSI, PSII, and pigment-binding proteins (PBPs)) of P. cordatum differed markedly from those of A. thaliana. Furthermore, a high number of PBPs was detected, accounting for a large share of the total proteomic data (∼65%) and potentially providing P. cordatum with flexible adaptation to changing light regimes.
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Affiliation(s)
- Jana Kalvelage
- Institute for Chemistry and Biology of the Marine Environment (ICBM), School of Mathematics and Science, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
| | - Lars Wöhlbrand
- Institute for Chemistry and Biology of the Marine Environment (ICBM), School of Mathematics and Science, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
| | - Jennifer Senkler
- Institute of Plant Genetics, Leibniz Universität Hannover, Hannover, Germany
| | - Julian Schumacher
- Institute for Chemistry and Biology of the Marine Environment (ICBM), School of Mathematics and Science, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
| | - Noah Ditz
- Institute of Plant Genetics, Leibniz Universität Hannover, Hannover, Germany
| | - Kai Bischof
- FB2 - Biology/Chemistry, University of Bremen, Bremen, Germany
| | - Michael Winklhofer
- Institute of Biology and Environmental Sciences (IBU), School of Mathematics and Science, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
- Research Center Neurosensory Science, School of Mathematics and Science, Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
| | - Andreas Klingl
- Botany, Ludwig-Maximilians-Universität LMU München, Planegg-Martinsried, Germany
| | - Hans-Peter Braun
- Institute of Plant Genetics, Leibniz Universität Hannover, Hannover, Germany
| | - Ralf Rabus
- Institute for Chemistry and Biology of the Marine Environment (ICBM), School of Mathematics and Science, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
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