Structure of NDH the complex I-like molecule of photosynthesis
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ABSTRACT:
SUBMITTER: Thomas Gerard Laughlin
PROVIDER: EMPIAR-10257 | biostudies-other |
REPOSITORIES: biostudies-other
Publications
Structure of the complex I-like molecule NDH of oxygenic photosynthesis.
Laughlin Thomas G TG Bayne Andrew N AN Trempe Jean-François JF Savage David F DF Davies Karen M KM
Nature 20190211 7744
Cyclic electron flow around photosystem I (PSI) is a mechanism by which photosynthetic organisms balance the levels of ATP and NADPH necessary for efficient photosynthesis<sup>1,2</sup>. NAD(P)H dehydrogenase-like complex (NDH) is a key component of this pathway in most oxygenic photosynthetic organisms<sup>3,4</sup> and is the last large photosynthetic membrane-protein complex for which the structure remains unknown. Related to the respiratory NADH dehydrogenase complex (complex I), NDH transfe ...[more]
Similar Datasets
Project description:Cyclic electron flow (CEF) around photosystem I (PSI) is a mechanism by which photosynthetic organisms balance levels of ATP and NADPH necessary for efficient photosynthesis1,2. The NAD(P)H dehydrogenase-like complex (NDH) is a key component of this pathway in most oxygenic photosynthetic organisms3,4 and the last large photosynthetic membrane protein complex of unknown structure. Related to the respiratory NADH dehydrogenase complex (complex I), NDH transfers electrons originating from PSI to the plastoquinone (PQ) pool, while pumping protons across the thylakoid membrane, thereby increasing the amount of ATP produced per NADP+ molecule reduced4,5. NDH possesses 11 of the 14 core complex I subunits as well as several oxygenic photosynthesis specific (OPS) subunits, which are conserved from cyanobacteria to higher plants3,6. However, the three complex I core subunits involved in accepting electrons from NAD(P)H are notably absent in NDH3,5,6. Thus, how NDH acquires and transfers electrons to PQ is presently unclear. Nevertheless, the OPS subunits, specifically NdhS, are proposed to enable NDH to accept electrons from ferredoxin (Fd), its electron donor3–5,7. Here we report a 3.1 Å structure of the ~0.42 MDa NDH complex from the thermophilic cyanobacterium Thermosynechoccous elongatus BP-1 (T. elongatus) obtained by single-particle cryo-electron microscopy (cryo-EM). Our maps reveal the structure and arrangement of the principle OPS subunits in the NDH complex, as well as an unexpected cofactor near the PQ-binding site in the peripheral arm. The location of the OPS subunits supports a role in electron transfer and defines two potential Fd-binding sites at the apex of the peripheral arm. Together, these results suggest multiple electron transfer routes could be present in NDH, which would serve to maximize PQ reduction and avoid deleterious off-target chemistry of the semi-plastoquinone radical.
2019-02-18 | PXD012206 | Pride
Project description:We have investigated the topologies of Ndh (a plastid complex with NADH dehydrogenase activity) and its NDH-F subunit in thylakoids by trypsin and proteinase V8 digestion of both intact and Triton X-100-permeabilized barley thylakoids and identification of the products with antibodies against specific sequences of the NDH-A, NDH-K and NDH-F subunits. Antibody binding and protection against proteinases were also assayed. The analysis of the digestion products of NDH-F by immunodetection and matrix-assisted laser-desorption ionization-time-of-flight allowed us to propose its membrane topology and to compare it with bioinformatic predictions and with that of the homologous subunit (ND5/NuoL/NQO12) of the respiratory complex I. Results indicate that the thylakoid Ndh complex may have an L-shaped structure, similar to that of respiratory complex I, with the hydrophilic arm orientated towards the stroma and the hydrophobic arm inserted into the thylakoid. NDH-A and NDH-K may be located at the bridge between the two arms. Similar to ND5/NuoL/NQO12 of complex I, NDH-F must be distally located in the hydrophobic arm. NDH-F would include up to 15 transmembrane helices and 14 hydrophilic regions. A conserved His-349 in the X transmembrane helix could be involved in H+ pumping. The conserved Thr-181 NDH-F, whose probable phosphorylation increases the activity of the Ndh complex, is located within the hydrophilic region between the V and VI transmembrane helices.
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Project description:Type II NADH:quinone oxidoreductase (NDH-2) is a proposed drug-target of major pathogenic microorganisms such as Mycobacterium tuberculosis and Plasmodium falciparum. Many NDH-2 inhibitors have been identified, but rational drug development is impeded by the lack of information regarding their mode of action and associated inhibitor-bound NDH-2 structure. We have determined the crystal structure of NDH-2 complexed with a quinolone inhibitor 2-heptyl-4-hydroxyquinoline-N-oxide (HQNO). HQNO is nested into the slot-shaped tunnel of the Q-site, in which the quinone-head group is clamped by Q317 and I379 residues, and hydrogen-bonds to FAD. The interaction of HQNO with bacterial NDH-2 is very similar to the native substrate ubiquinone (UQ1) interactions in the yeast Ndi1-UQ1 complex structure, suggesting a conserved mechanism for quinone binding. Further, the structural analysis provided insight how modifications of quinolone scaffolds improve potency (e.g. quinolinyl pyrimidine derivatives) and suggests unexplored target space for the rational design of new NDH-2 inhibitors.
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Project description:NDH-1 is a gigantic redox-driven proton pump linked with respiration and cyclic electron flow in cyanobacterial cells. Based on experimentally resolved X-ray and cryo-EM structures of the respiratory complex I, we derive here molecular models of two isoforms of the cyanobacterial NDH-1 complex involved in redox-driven proton pumping (NDH-1L) and CO2-fixation (NDH-1MS). Our models show distinct structural and dynamic similarities to the core architecture of the bacterial and mammalian respiratory complex I. We identify putative plastoquinone-binding sites that are coupled by an electrostatic wire to the proton pumping elements in the membrane domain of the enzyme. Molecular simulations suggest that the NDH-1L isoform undergoes large-scale hydration changes that support proton-pumping within antiporter-like subunits, whereas the terminal subunit of the NDH-1MS isoform lacks such structural motifs. Our work provides a putative molecular blueprint for the complex I-analogue in the photosynthetic energy transduction machinery and demonstrates that general mechanistic features of the long-range proton-pumping machinery are evolutionary conserved in the complex I-superfamily.
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Project description:The NuoD segment (homologue of mitochondrial 49 kDa subunit) of the proton-translocating NADH:quinone oxidoreductase (complex I/NDH-1) from Escherichia coli is in the hydrophilic domain and bears many highly conserved amino acid residues. The three-dimensional structural model of NDH-1 suggests that the NuoD segment, together with the neighboring subunits, constitutes a putative quinone binding cavity. We used the homologous DNA recombination technique to clarify the role of selected key amino acid residues of the NuoD segment. Among them, residues Tyr273 and His224 were considered candidates for having important interactions with the quinone headgroup. Mutant Y273F retained partial activity but lost sensitivity to capsaicin-40. Mutant H224R scarcely affected the activity, suggesting that this residue may not be essential. His224 is located in a loop near the N-terminus of the NuoD segment (Gly217-Phe227) which is considered to form part of the quinone binding cavity. In contrast to the His224 mutation, mutants G217V, P218A, and G225V almost completely lost the activity. One region of this loop is positioned close to a cytosolic loop of the NuoA subunit in the membrane domain, and together they seem to be important in keeping the quinone binding cavity intact. The structural role of the longest helix in the NuoD segment located behind the quinone binding cavity was also investigated. Possible roles of other highly conserved residues of the NuoD segment are discussed.
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2024-10-23 | GSE278422 | GEO
Project description:Here, we have compiled a nuclear magnetic resonance (NMR)-derived set of nuclear Overhauser enhancement (NOE) distance and dihedral angle restraints that allow for the calculation of the structure of the NDH-1 complex subunit CupS from Thermosynechococcus elongatus in solution. These restraints to calculate the structure in solution of CupS have been deposited to the Protein Data Bank (www.rcsb.org) under PDB-ID accession number 2MXA. This is the first experimental data set published to compute the three-dimensional structure of CupS. This structure is presented in the research article "Solution structure of the NDH-1 complex subunit CupS from Thermosynechococcus elongatus" published by Korste et al. in Biochim. Biophys. Acta 1847(2015)1212-1219 [1]. The cyanobacterial multi-subunit membrane protein complex NDH-1 structurally and functionally relates to Complex I of eubacteria and mitochondria. The NDH-1 complex is mechanistically involved in respiration and cyclic electron transfer around photosystem I (PSI) as well as in a unique mechanism for inorganic carbon concentration.
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