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Mehra HS, Wang X, Russell BP, Kulkarni N, Ferrari N, Larson B, Vinyard DJ. Assembly and Repair of Photosystem II in Chlamydomonas reinhardtii. Plants (Basel) 2024; 13:811. [PMID: 38592843 PMCID: PMC10975043 DOI: 10.3390/plants13060811] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 03/05/2024] [Accepted: 03/07/2024] [Indexed: 04/11/2024]
Abstract
Oxygenic photosynthetic organisms use Photosystem II (PSII) to oxidize water and reduce plastoquinone. Here, we review the mechanisms by which PSII is assembled and turned over in the model green alga Chlamydomonas reinhardtii. This species has been used to make key discoveries in PSII research due to its metabolic flexibility and amenability to genetic approaches. PSII subunits originate from both nuclear and chloroplastic gene products in Chlamydomonas. Nuclear-encoded PSII subunits are transported into the chloroplast and chloroplast-encoded PSII subunits are translated by a coordinated mechanism. Active PSII dimers are built from discrete reaction center complexes in a process facilitated by assembly factors. The phosphorylation of core subunits affects supercomplex formation and localization within the thylakoid network. Proteolysis primarily targets the D1 subunit, which when replaced, allows PSII to be reactivated and completes a repair cycle. While PSII has been extensively studied using Chlamydomonas as a model species, important questions remain about its assembly and repair which are presented here.
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Affiliation(s)
| | | | | | | | | | | | - David J. Vinyard
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA; (H.S.M.); (X.W.); (B.P.R.); (N.K.); (N.F.); (B.L.)
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2
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Russell BP, Vinyard DJ. Conformational changes in a Photosystem II hydrogen bond network stabilize the oxygen-evolving complex. Biochim Biophys Acta Bioenerg 2024; 1865:149020. [PMID: 37956939 DOI: 10.1016/j.bbabio.2023.149020] [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] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 10/26/2023] [Accepted: 11/06/2023] [Indexed: 11/19/2023]
Abstract
The Mn4CaO5 oxygen-evolving complex (OEC) in Photosystem II (PSII) is assembled in situ and catalyzes water oxidation. After OEC assembly, the PsbO extrinsic subunit docks to the lumenal face of PSII and both stabilizes the OEC and facilitates efficient proton transfer to the lumen. D1 residue R334 is part of a hydrogen bond network involved in proton release during catalysis and interacts directly with PsbO. D1-R334 has recently been observed in different conformations in apo- and holo-OEC PSII structures. We generated a D1-R334G point mutant in Synechocystis sp. PCC 6803 to better understand this residue's function. D1-R334G PSII is active under continuous light, but the OEC is unstable in darkness. Isolated D1-R334G core complexes have little bound PsbO and less manganese as the wild type control. The S2 intermediate is stabilized in D1-R334G indicating that the local environment around the OEC has been altered. These results suggest that the hydrogen bond network that includes D1-R334 exists in a different functional conformation during PSII biogenesis in the absence of PsbO.
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Affiliation(s)
- Brandon P Russell
- Department of Biological Sciences, Louisiana State University, 202 Life Sciences Building, Baton Rouge, LA 70803, United States of America
| | - David J Vinyard
- Department of Biological Sciences, Louisiana State University, 202 Life Sciences Building, Baton Rouge, LA 70803, United States of America.
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3
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Hood DM, Johnson RA, Vinyard DJ, Fronczek FR, Stanley GG. Cationic Cobalt(II) Bisphosphine Hydroformylation Catalysis: In Situ Spectroscopic and Reaction Studies. J Am Chem Soc 2023; 145:19715-19726. [PMID: 37642952 DOI: 10.1021/jacs.3c04866] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
[HCo(CO)x(bisphosphine)](BF4), x = 1-3, is a highly active hydroformylation catalyst system, especially for internal branched alkenes. In situ infrared spectroscopy (IR), electron paramagnetic resonance (EPR), and nuclear magnetic resonance studies support the proposed catalyst formulation. IR studies reveal the formation of a dicationic Co(I) paramagnetic CO-bridged dimer, [Co2(μ-CO)2(CO)(bisphosphine)2]2+, at lower temperatures formed from the reaction of two catalyst complexes via the elimination of H2. DFT studies indicate a dimer structure with square-pyramidal and tetrahedral cobalt centers. This monomer-dimer equilibrium is analogous to that seen for HCo(CO)4, reacting to eliminate H2 and form Co2(CO)8. EPR studies on the catalyst show a high-spin (S = 3/2) Co(II) complex. Reaction studies are presented that support the cationic Co(II) bisphosphine catalyst as the catalyst species present in this system and minimize the possible role of neutral Co(I) species, HCo(CO)4 or HCo(CO)3(phosphine), as catalysts.
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Affiliation(s)
- Drew M Hood
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803-1804, United States
| | - Ryan A Johnson
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803-1804, United States
| | - David J Vinyard
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803-1804, United States
| | - Frank R Fronczek
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803-1804, United States
| | - George G Stanley
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803-1804, United States
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4
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Vinyard DJ. A low-cost and realistic noisy light system for studying photosynthesis. Photosynth Res 2023:10.1007/s11120-023-01012-2. [PMID: 36941457 DOI: 10.1007/s11120-023-01012-2] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 03/08/2023] [Indexed: 05/25/2023]
Abstract
Unlike the light conditions commonly used to grow photosynthetic organisms in the research laboratory, the light intensity in real environments is dynamic. A simple and low-cost system is described in which a commercial dimmable LED panel is controlled to simulate a sinusoidal function representing daylight hours and overlaid with stochastic shading events. The output closely resembles light intensity measurements on Earth's surface on partly cloudy days or in lower levels of plant canopies. This tool may be useful to researchers studying photosynthetic acclimation responses.
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Affiliation(s)
- David J Vinyard
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA.
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5
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Russell BP, Vinyard DJ. Chloride facilitates Mn(III) formation during photoassembly of the Photosystem II oxygen-evolving complex. Photosynth Res 2022; 152:283-288. [PMID: 34817779 DOI: 10.1007/s11120-021-00886-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 11/12/2021] [Indexed: 06/13/2023]
Abstract
The Mn4Ca oxygen-evolving complex (OEC) in Photosystem II (PSII) is assembled in situ from free Mn2+, Ca2+, and water. In an early light-driven step, Mn2+ in a protein high-affinity site is oxidized to Mn3+. Using dual-mode electron paramagnetic resonance spectroscopy, we observed that Mn3+ accumulation increases as chloride concentration increases in spinach PSII membranes depleted of all extrinsic subunits. At physiologically relevant pH values, this effect requires the presence of calcium. When combined with pH studies, we conclude that the first Mn2+ oxidation event in OEC assembly requires a deprotonation that is facilitated by chloride.
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Affiliation(s)
- Brandon P Russell
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - David J Vinyard
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA.
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Gisriel CJ, Shen G, Ho MY, Kurashov V, Flesher DA, Wang J, Armstrong WH, Golbeck JH, Gunner MR, Vinyard DJ, Debus RJ, Brudvig GW, Bryant DA. Structure of a monomeric photosystem II core complex from a cyanobacterium acclimated to far-red light reveals the functions of chlorophylls d and f. J Biol Chem 2022; 298:101424. [PMID: 34801554 PMCID: PMC8689208 DOI: 10.1016/j.jbc.2021.101424] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Revised: 11/12/2021] [Accepted: 11/13/2021] [Indexed: 11/26/2022] Open
Abstract
Far-red light (FRL) photoacclimation in cyanobacteria provides a selective growth advantage for some terrestrial cyanobacteria by expanding the range of photosynthetically active radiation to include far-red/near-infrared light (700-800 nm). During this photoacclimation process, photosystem II (PSII), the water:plastoquinone photooxidoreductase involved in oxygenic photosynthesis, is modified. The resulting FRL-PSII is comprised of FRL-specific core subunits and binds chlorophyll (Chl) d and Chl f molecules in place of several of the Chl a molecules found when cells are grown in visible light. These new Chls effectively lower the energy canonically thought to define the "red limit" for light required to drive photochemical catalysis of water oxidation. Changes to the architecture of FRL-PSII were previously unknown, and the positions of Chl d and Chl f molecules had only been proposed from indirect evidence. Here, we describe the 2.25 Å resolution cryo-EM structure of a monomeric FRL-PSII core complex from Synechococcus sp. PCC 7335 cells that were acclimated to FRL. We identify one Chl d molecule in the ChlD1 position of the electron transfer chain and four Chl f molecules in the core antenna. We also make observations that enhance our understanding of PSII biogenesis, especially on the acceptor side of the complex where a bicarbonate molecule is replaced by a glutamate side chain in the absence of the assembly factor Psb28. In conclusion, these results provide a structural basis for the lower energy limit required to drive water oxidation, which is the gateway for most solar energy utilization on earth.
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Affiliation(s)
| | - Gaozhong Shen
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Ming-Yang Ho
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, USA; Intercollege Graduate Program in Plant Biology, The Pennsylvania State University, University Park, Pennsylvania, USA; Department of Life Science, National Taiwan University, Taipei, Taiwan
| | - Vasily Kurashov
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - David A Flesher
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Jimin Wang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | | | - John H Golbeck
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, USA; Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Marilyn R Gunner
- Department of Physics, City College of New York, New York, New York, USA
| | - David J Vinyard
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, USA
| | - Richard J Debus
- Department of Biochemistry, University of California, Riverside, California, USA
| | - Gary W Brudvig
- Department of Chemistry, Yale University, New Haven, Connecticut, USA; Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA.
| | - Donald A Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, USA; Intercollege Graduate Program in Plant Biology, The Pennsylvania State University, University Park, Pennsylvania, USA.
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7
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Hood DM, Johnson RA, Carpenter AE, Younker JM, Vinyard DJ, Stanley GG. Highly active cationic cobalt(II) hydroformylation catalysts. Science 2020; 367:542-548. [DOI: 10.1126/science.aaw7742] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 12/23/2019] [Indexed: 11/02/2022]
Abstract
The cobalt complexes HCo(CO)4 and HCo(CO)3(PR3) were the original industrial catalysts used for the hydroformylation of alkenes through reaction with hydrogen and carbon monoxide to produce aldehydes. More recent and expensive rhodium-phosphine catalysts are hundreds of times more active and operate under considerably lower pressures. Cationic cobalt(II) bisphosphine hydrido-carbonyl catalysts that are far more active than traditional neutral cobalt(I) catalysts and approach rhodium catalysts in activity are reported here. These catalysts have low linear-to-branched (L:B) regioselectivity for simple linear alkenes. However, owing to their high alkene isomerization activity and increased steric effects due to the bisphosphine ligand, they have high L:B selectivities for internal alkenes with alkyl branches. These catalysts exhibit long lifetimes and substantial resistance to degradation reactions.
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Affiliation(s)
- Drew M. Hood
- Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Ryan A. Johnson
- Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA
| | | | | | - David J. Vinyard
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - George G. Stanley
- Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA
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8
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Zhao C, Lyu Z, Long F, Akinyemi T, Manakongtreecheep K, Söll D, Whitman WB, Vinyard DJ, Liu Y. The Nbp35/ApbC homolog acts as a nonessential [4Fe-4S] transfer protein in methanogenic archaea. FEBS Lett 2019; 594:924-932. [PMID: 31709520 DOI: 10.1002/1873-3468.13673] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 11/04/2019] [Accepted: 11/05/2019] [Indexed: 01/09/2023]
Abstract
The nucleotide binding protein 35 (Nbp35)/cytosolic Fe-S cluster deficient 1 (Cfd1)/alternative pyrimidine biosynthetic protein C (ApbC) protein homologs have been identified in all three domains of life. In eukaryotes, the Nbp35/Cfd1 heterocomplex is an essential Fe-S cluster assembly scaffold required for the maturation of Fe-S proteins in the cytosol and nucleus, whereas the bacterial ApbC is an Fe-S cluster transfer protein only involved in the maturation of a specific target protein. Here, we show that the Nbp35/ApbC homolog MMP0704 purified from its native archaeal host Methanococcus maripaludis contains a [4Fe-4S] cluster that can be transferred to a [4Fe-4S] apoprotein. Deletion of mmp0704 from M. maripaludis does not cause growth deficiency under our tested conditions. Our data indicate that Nbp35/ApbC is a nonessential [4Fe-4S] cluster transfer protein in methanogenic archaea.
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Affiliation(s)
- Cuiping Zhao
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, USA
| | - Zhe Lyu
- Department of Microbiology, University of Georgia, Athens, GA, USA
| | - Feng Long
- Department of Microbiology, University of Georgia, Athens, GA, USA
| | - Taiwo Akinyemi
- Department of Microbiology, University of Georgia, Athens, GA, USA
| | | | - Dieter Söll
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.,Department of Chemistry, Yale University, New Haven, CT, USA
| | | | - David J Vinyard
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, USA
| | - Yuchen Liu
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, USA
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9
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Ghosh I, Khan S, Banerjee G, Dziarski A, Vinyard DJ, Debus RJ, Brudvig GW. Insights into Proton-Transfer Pathways during Water Oxidation in Photosystem II. J Phys Chem B 2019; 123:8195-8202. [DOI: 10.1021/acs.jpcb.9b06244] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ipsita Ghosh
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Sahr Khan
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Gourab Banerjee
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Alisha Dziarski
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - David J. Vinyard
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Richard J. Debus
- Department of Biochemistry, University of California, Riverside, California 92521, United States
| | - Gary W. Brudvig
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
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10
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Mukherjee A, Lau CS, Walker CE, Rai AK, Prejean CI, Yates G, Emrich-Mills T, Lemoine SG, Vinyard DJ, Mackinder LCM, Moroney JV. Thylakoid localized bestrophin-like proteins are essential for the CO 2 concentrating mechanism of Chlamydomonas reinhardtii. Proc Natl Acad Sci U S A 2019; 116:16915-16920. [PMID: 31391312 DOI: 10.1073/pnas.190970611] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/19/2023] Open
Abstract
The green alga Chlamydomonas reinhardtii possesses a CO2 concentrating mechanism (CCM) that helps in successful acclimation to low CO2 conditions. Current models of the CCM postulate that a series of ion transporters bring HCO3- from outside the cell to the thylakoid lumen, where the carbonic anhydrase 3 (CAH3) dehydrates accumulated HCO3- to CO2, raising the CO2 concentration for Ribulose bisphosphate carboxylase/oxygenase (Rubisco). Previously, HCO3- transporters have been identified at both the plasma membrane and the chloroplast envelope, but the transporter thought to be on the thylakoid membrane has not been identified. Three paralogous genes (BST1, BST2, and BST3) belonging to the bestrophin family have been found to be up-regulated in low CO2 conditions, and their expression is controlled by CIA5, a transcription factor that controls many CCM genes. YFP fusions demonstrate that all 3 proteins are located on the thylakoid membrane, and interactome studies indicate that they might associate with chloroplast CCM components. A single mutant defective in BST3 has near-normal growth on low CO2, indicating that the 3 bestrophin-like proteins may have redundant functions. Therefore, an RNA interference (RNAi) approach was adopted to reduce the expression of all 3 genes at once. RNAi mutants with reduced expression of BST1-3 were unable to grow at low CO2 concentrations, exhibited a reduced affinity to inorganic carbon (Ci) compared with the wild-type cells, and showed reduced Ci uptake. We propose that these bestrophin-like proteins are essential components of the CCM that deliver HCO3- accumulated in the chloroplast stroma to CAH3 inside the thylakoid lumen.
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Affiliation(s)
- Ananya Mukherjee
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803
| | - Chun Sing Lau
- Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Charlotte E Walker
- Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Ashwani K Rai
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803
| | - Camille I Prejean
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803
| | - Gary Yates
- Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Thomas Emrich-Mills
- Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Spencer G Lemoine
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803
| | - David J Vinyard
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803
| | - Luke C M Mackinder
- Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom
| | - James V Moroney
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803;
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11
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Vinyard DJ, Ananyev GM, Dismukes GC. Desiccation tolerant lichens facilitate in vivo H/D isotope effect measurements in oxygenic photosynthesis. Biochimica et Biophysica Acta (BBA) - Bioenergetics 2018; 1859:1039-1044. [DOI: 10.1016/j.bbabio.2018.05.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 05/21/2018] [Accepted: 05/23/2018] [Indexed: 10/14/2022]
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12
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Bonyhady SJ, DeRosha DE, Vela J, Vinyard DJ, Cowley RE, Mercado BQ, Brennessel WW, Holland PL. Iron and Cobalt Diazoalkane Complexes Supported by β-Diketiminate Ligands: A Synthetic, Spectroscopic, and Computational Investigation. Inorg Chem 2018; 57:5959-5972. [DOI: 10.1021/acs.inorgchem.8b00468] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Simon J. Bonyhady
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Daniel E. DeRosha
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Javier Vela
- Department of Chemistry, University of Rochester, 120 Trustee Road, Rochester, New York 14627, United States
| | - David J. Vinyard
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Ryan E. Cowley
- Department of Chemistry, University of Rochester, 120 Trustee Road, Rochester, New York 14627, United States
| | - Brandon Q. Mercado
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - William W. Brennessel
- Department of Chemistry, University of Rochester, 120 Trustee Road, Rochester, New York 14627, United States
| | - Patrick L. Holland
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
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13
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Lee MY, Gamez-Mendez A, Zhang J, Zhuang Z, Vinyard DJ, Kraehling J, Velazquez H, Brudvig GW, Kyriakides TR, Simons M, Sessa WC. Endothelial Cell Autonomous Role of Akt1: Regulation of Vascular Tone and Ischemia-Induced Arteriogenesis. Arterioscler Thromb Vasc Biol 2018; 38:870-879. [PMID: 29449333 DOI: 10.1161/atvbaha.118.310748] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 01/25/2018] [Indexed: 12/30/2022]
Abstract
OBJECTIVE The importance of PI3K/Akt signaling in the vasculature has been demonstrated in several models, as global loss of Akt1 results in impaired postnatal ischemia- and VEGF-induced angiogenesis. The ubiquitous expression of Akt1, however, raises the possibility of cell-type-dependent Akt1-driven actions, thereby necessitating tissue-specific characterization. APPROACH AND RESULTS Herein, we used an inducible, endothelial-specific Akt1-deleted adult mouse model (Akt1iECKO) to characterize the endothelial cell autonomous functions of Akt1 in the vascular system. Endothelial-targeted ablation of Akt1 reduces eNOS (endothelial nitric oxide synthase) phosphorylation and promotes both increased vascular contractility in isolated vessels and elevated diastolic blood pressures throughout the diurnal cycle in vivo. Furthermore, Akt1iECKO mice subject to the hindlimb ischemia model display impaired blood flow and decreased arteriogenesis. CONCLUSIONS Endothelial Akt1 signaling is necessary for ischemic resolution post-injury and likely reflects the consequence of NO insufficiency critical for vascular repair.
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Affiliation(s)
- Monica Y Lee
- From the Vascular Biology and Therapeutics Program, Department of Pharmacology (M.Y.L., A.G.-M., J.K., W.C.S.), Vascular Biology and Therapeutics Program, Department of Pathology (T.R.K.), and Department of Cell Biology (M.S.), Yale University School of Medicine, New Haven, CT; Department of Internal Medicine, Section of Cardiovascular Medicine, Yale Cardiovascular Research Center, New Haven, CT (J.Z., Z.Z., M.S.); Department of Chemistry, Yale University, New Haven, CT (D.J.V., G.W.B.); and Department of Internal Medicine, VA Connecticut Healthcare System, West Haven, CT (H.V.)
| | - Ana Gamez-Mendez
- From the Vascular Biology and Therapeutics Program, Department of Pharmacology (M.Y.L., A.G.-M., J.K., W.C.S.), Vascular Biology and Therapeutics Program, Department of Pathology (T.R.K.), and Department of Cell Biology (M.S.), Yale University School of Medicine, New Haven, CT; Department of Internal Medicine, Section of Cardiovascular Medicine, Yale Cardiovascular Research Center, New Haven, CT (J.Z., Z.Z., M.S.); Department of Chemistry, Yale University, New Haven, CT (D.J.V., G.W.B.); and Department of Internal Medicine, VA Connecticut Healthcare System, West Haven, CT (H.V.)
| | - Jiasheng Zhang
- From the Vascular Biology and Therapeutics Program, Department of Pharmacology (M.Y.L., A.G.-M., J.K., W.C.S.), Vascular Biology and Therapeutics Program, Department of Pathology (T.R.K.), and Department of Cell Biology (M.S.), Yale University School of Medicine, New Haven, CT; Department of Internal Medicine, Section of Cardiovascular Medicine, Yale Cardiovascular Research Center, New Haven, CT (J.Z., Z.Z., M.S.); Department of Chemistry, Yale University, New Haven, CT (D.J.V., G.W.B.); and Department of Internal Medicine, VA Connecticut Healthcare System, West Haven, CT (H.V.)
| | - Zhenwu Zhuang
- From the Vascular Biology and Therapeutics Program, Department of Pharmacology (M.Y.L., A.G.-M., J.K., W.C.S.), Vascular Biology and Therapeutics Program, Department of Pathology (T.R.K.), and Department of Cell Biology (M.S.), Yale University School of Medicine, New Haven, CT; Department of Internal Medicine, Section of Cardiovascular Medicine, Yale Cardiovascular Research Center, New Haven, CT (J.Z., Z.Z., M.S.); Department of Chemistry, Yale University, New Haven, CT (D.J.V., G.W.B.); and Department of Internal Medicine, VA Connecticut Healthcare System, West Haven, CT (H.V.)
| | - David J Vinyard
- From the Vascular Biology and Therapeutics Program, Department of Pharmacology (M.Y.L., A.G.-M., J.K., W.C.S.), Vascular Biology and Therapeutics Program, Department of Pathology (T.R.K.), and Department of Cell Biology (M.S.), Yale University School of Medicine, New Haven, CT; Department of Internal Medicine, Section of Cardiovascular Medicine, Yale Cardiovascular Research Center, New Haven, CT (J.Z., Z.Z., M.S.); Department of Chemistry, Yale University, New Haven, CT (D.J.V., G.W.B.); and Department of Internal Medicine, VA Connecticut Healthcare System, West Haven, CT (H.V.)
| | - Jan Kraehling
- From the Vascular Biology and Therapeutics Program, Department of Pharmacology (M.Y.L., A.G.-M., J.K., W.C.S.), Vascular Biology and Therapeutics Program, Department of Pathology (T.R.K.), and Department of Cell Biology (M.S.), Yale University School of Medicine, New Haven, CT; Department of Internal Medicine, Section of Cardiovascular Medicine, Yale Cardiovascular Research Center, New Haven, CT (J.Z., Z.Z., M.S.); Department of Chemistry, Yale University, New Haven, CT (D.J.V., G.W.B.); and Department of Internal Medicine, VA Connecticut Healthcare System, West Haven, CT (H.V.)
| | - Heino Velazquez
- From the Vascular Biology and Therapeutics Program, Department of Pharmacology (M.Y.L., A.G.-M., J.K., W.C.S.), Vascular Biology and Therapeutics Program, Department of Pathology (T.R.K.), and Department of Cell Biology (M.S.), Yale University School of Medicine, New Haven, CT; Department of Internal Medicine, Section of Cardiovascular Medicine, Yale Cardiovascular Research Center, New Haven, CT (J.Z., Z.Z., M.S.); Department of Chemistry, Yale University, New Haven, CT (D.J.V., G.W.B.); and Department of Internal Medicine, VA Connecticut Healthcare System, West Haven, CT (H.V.)
| | - Gary W Brudvig
- From the Vascular Biology and Therapeutics Program, Department of Pharmacology (M.Y.L., A.G.-M., J.K., W.C.S.), Vascular Biology and Therapeutics Program, Department of Pathology (T.R.K.), and Department of Cell Biology (M.S.), Yale University School of Medicine, New Haven, CT; Department of Internal Medicine, Section of Cardiovascular Medicine, Yale Cardiovascular Research Center, New Haven, CT (J.Z., Z.Z., M.S.); Department of Chemistry, Yale University, New Haven, CT (D.J.V., G.W.B.); and Department of Internal Medicine, VA Connecticut Healthcare System, West Haven, CT (H.V.)
| | - Themis R Kyriakides
- From the Vascular Biology and Therapeutics Program, Department of Pharmacology (M.Y.L., A.G.-M., J.K., W.C.S.), Vascular Biology and Therapeutics Program, Department of Pathology (T.R.K.), and Department of Cell Biology (M.S.), Yale University School of Medicine, New Haven, CT; Department of Internal Medicine, Section of Cardiovascular Medicine, Yale Cardiovascular Research Center, New Haven, CT (J.Z., Z.Z., M.S.); Department of Chemistry, Yale University, New Haven, CT (D.J.V., G.W.B.); and Department of Internal Medicine, VA Connecticut Healthcare System, West Haven, CT (H.V.)
| | - Michael Simons
- From the Vascular Biology and Therapeutics Program, Department of Pharmacology (M.Y.L., A.G.-M., J.K., W.C.S.), Vascular Biology and Therapeutics Program, Department of Pathology (T.R.K.), and Department of Cell Biology (M.S.), Yale University School of Medicine, New Haven, CT; Department of Internal Medicine, Section of Cardiovascular Medicine, Yale Cardiovascular Research Center, New Haven, CT (J.Z., Z.Z., M.S.); Department of Chemistry, Yale University, New Haven, CT (D.J.V., G.W.B.); and Department of Internal Medicine, VA Connecticut Healthcare System, West Haven, CT (H.V.)
| | - William C Sessa
- From the Vascular Biology and Therapeutics Program, Department of Pharmacology (M.Y.L., A.G.-M., J.K., W.C.S.), Vascular Biology and Therapeutics Program, Department of Pathology (T.R.K.), and Department of Cell Biology (M.S.), Yale University School of Medicine, New Haven, CT; Department of Internal Medicine, Section of Cardiovascular Medicine, Yale Cardiovascular Research Center, New Haven, CT (J.Z., Z.Z., M.S.); Department of Chemistry, Yale University, New Haven, CT (D.J.V., G.W.B.); and Department of Internal Medicine, VA Connecticut Healthcare System, West Haven, CT (H.V.).
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14
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Affiliation(s)
- David J. Vinyard
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803
| | - Gary W. Brudvig
- Department of Chemistry, Yale University, New Haven, Connecticut 06520
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15
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Peper JL, Vinyard DJ, Brudvig GW, Mayer JM. Slow Equilibration between Spectroscopically Distinct Trap States in Reduced TiO2 Nanoparticles. J Am Chem Soc 2017; 139:2868-2871. [DOI: 10.1021/jacs.6b12112] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jennifer L. Peper
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - David J. Vinyard
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Gary W. Brudvig
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - James M. Mayer
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
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16
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Shopov DY, Rudshteyn B, Campos J, Vinyard DJ, Batista VS, Brudvig GW, Crabtree RH. A full set of iridium(iv) pyridine-alkoxide stereoisomers: highly geometry-dependent redox properties. Chem Sci 2017; 8:1642-1652. [PMID: 28451293 PMCID: PMC5364517 DOI: 10.1039/c6sc03758e] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2016] [Accepted: 11/06/2016] [Indexed: 11/21/2022] Open
Abstract
We introduce and characterize the complete set of possible isomers of IrIV(pyalk)2Cl2 (pyalk = 2-(pyridin-2-yl)propan-2-oate), providing valuable insights on the properties of Ir(iv) species. The pyridine alkoxide ligand strongly stabilizes high oxidation states, essential to accessing the catalytically relevant Ir(iv) state, and results in robust complexes that can be handled under ambient conditions, even permitting chromatographic separation. The redox properties are isomer-dependent, spanning a 300 mV range, rationalized with ligand-field theory and DFT calculations. The reported complexes exhibit very high kinetic inertness against isomerization, despite highly disparate predicted thermodynamic stabilities, presenting a unique opportunity to study all five possible isomeric complexes with the same ligand set.
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Affiliation(s)
- Dimitar Y Shopov
- Department of Chemistry , Yale University , 225 Prospect St. , New Haven , CT 06520 , United States
| | - Benjamin Rudshteyn
- Department of Chemistry , Yale University , 225 Prospect St. , New Haven , CT 06520 , United States
- Energy Sciences Institute , Yale University , 520 West Campus Dr. , West Haven , CT 06516 , United States
| | - Jesús Campos
- Department of Chemistry , Yale University , 225 Prospect St. , New Haven , CT 06520 , United States
- Instituto de Investigaciones Químicas (IIQ) , Departamento de Química Inorgánica and Centro de Innovación en Química Avanzada (ORFEO-CINQA) , Universidad de Sevilla and Consejo Superior de Investigaciones Científicas (CSIC) , Avenida Américo Vespucio 49 , 41092 Sevilla , Spain
| | - David J Vinyard
- Department of Chemistry , Yale University , 225 Prospect St. , New Haven , CT 06520 , United States
- Department of Biological Sciences , Louisiana State University , Baton Rouge , LA 70803 , USA
| | - Victor S Batista
- Department of Chemistry , Yale University , 225 Prospect St. , New Haven , CT 06520 , United States
- Energy Sciences Institute , Yale University , 520 West Campus Dr. , West Haven , CT 06516 , United States
| | - Gary W Brudvig
- Department of Chemistry , Yale University , 225 Prospect St. , New Haven , CT 06520 , United States
- Energy Sciences Institute , Yale University , 520 West Campus Dr. , West Haven , CT 06516 , United States
| | - Robert H Crabtree
- Department of Chemistry , Yale University , 225 Prospect St. , New Haven , CT 06520 , United States
- Energy Sciences Institute , Yale University , 520 West Campus Dr. , West Haven , CT 06516 , United States
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17
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Vinyard DJ, Khan S, Askerka M, Batista VS, Brudvig GW. Energetics of the S 2 State Spin Isomers of the Oxygen-Evolving Complex of Photosystem II. J Phys Chem B 2017; 121:1020-1025. [PMID: 28079373 DOI: 10.1021/acs.jpcb.7b00110] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The S2 redox intermediate of the oxygen-evolving complex in photosystem II is present as two spin isomers. The S = 1/2 isomer gives rise to a multiline electron paramagnetic resonance (EPR) signal at g = 2.0, whereas the S = 5/2 isomer exhibits a broad EPR signal at g = 4.1. The electronic structures of these isomers are known, but their role in the catalytic cycle of water oxidation remains unclear. We show that formation of the S = 1/2 state from the S = 5/2 state is exergonic at temperatures above 160 K. However, the S = 1/2 isomer decays to S1 more slowly than the S = 5/2 isomer. These differences support the hypotheses that the S3 state is formed via the S2 state S = 5/2 isomer and that the stabilized S2 state S = 1/2 isomer plays a role in minimizing S2QA- decay under light-limiting conditions.
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Affiliation(s)
- David J Vinyard
- Department of Chemistry, Yale University , New Haven, Connecticut 06520-8107, United States
| | - Sahr Khan
- Department of Chemistry, Yale University , New Haven, Connecticut 06520-8107, United States
| | - Mikhail Askerka
- Department of Chemistry, Yale University , New Haven, Connecticut 06520-8107, United States
| | - Victor S Batista
- Department of Chemistry, Yale University , New Haven, Connecticut 06520-8107, United States
| | - Gary W Brudvig
- Department of Chemistry, Yale University , New Haven, Connecticut 06520-8107, United States
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18
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Beromi MM, Nova A, Balcells D, Brasacchio AM, Brudvig GW, Guard LM, Hazari N, Vinyard DJ. Mechanistic Study of an Improved Ni Precatalyst for Suzuki-Miyaura Reactions of Aryl Sulfamates: Understanding the Role of Ni(I) Species. J Am Chem Soc 2017; 139:922-936. [PMID: 28009513 PMCID: PMC5360380 DOI: 10.1021/jacs.6b11412] [Citation(s) in RCA: 108] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Nickel precatalysts are potentially a more sustainable alternative to traditional palladium precatalysts for the Suzuki-Miyaura coupling reaction. Currently, there is significant interest in Suzuki-Miyaura coupling reactions involving readily accessible phenolic derivatives such as aryl sulfamates, as the sulfamate moiety can act as a directing group for the prefunctionalization of the aromatic backbone of the electrophile prior to cross-coupling. By evaluating complexes in the Ni(0), (I), and (II) oxidation states we report a precatalyst, (dppf)Ni(o-tolyl)(Cl) (dppf = 1,1'-bis(diphenylphosphino)ferrocene), for Suzuki-Miyaura coupling reactions involving aryl sulfamates and boronic acids, which operates at a significantly lower catalyst loading and at milder reaction conditions than other reported systems. In some cases it can even function at room temperature. Mechanistic studies on precatalyst activation and the speciation of nickel during catalysis reveal that Ni(I) species are formed in the catalytic reaction via two different pathways: (i) the precatalyst (dppf)Ni(o-tolyl)(Cl) undergoes comproportionation with the active Ni(0) species; and (ii) the catalytic intermediate (dppf)Ni(Ar)(sulfamate) (Ar = aryl) undergoes comproportionation with the active Ni(0) species. In both cases the formation of Ni(I) is detrimental to catalysis, which is proposed to proceed via a Ni(0)/Ni(II) cycle. DFT calculations are used to support experimental observations and provide insight about the elementary steps involved in reactions directly on the catalytic cycle, as well as off-cycle processes. Our mechanistic investigation provides guidelines for designing even more active nickel catalysts.
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Affiliation(s)
- Megan Mohadjer Beromi
- The Department of Chemistry, Yale University, P.O. Box 208107, New Haven, Connecticut 06520, United States
| | - Ainara Nova
- Centre for Theoretical and Computational Chemistry (CTCC), Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, 0315, Oslo, Norway
| | - David Balcells
- Centre for Theoretical and Computational Chemistry (CTCC), Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, 0315, Oslo, Norway
| | - Ann M. Brasacchio
- The Department of Chemistry, Yale University, P.O. Box 208107, New Haven, Connecticut 06520, United States
| | - Gary W. Brudvig
- The Department of Chemistry, Yale University, P.O. Box 208107, New Haven, Connecticut 06520, United States
| | - Louise M. Guard
- The Department of Chemistry, Yale University, P.O. Box 208107, New Haven, Connecticut 06520, United States
| | - Nilay Hazari
- The Department of Chemistry, Yale University, P.O. Box 208107, New Haven, Connecticut 06520, United States
| | - David J. Vinyard
- The Department of Chemistry, Yale University, P.O. Box 208107, New Haven, Connecticut 06520, United States
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19
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Affiliation(s)
- Daria L. Huang
- Department
of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - David J. Vinyard
- Department
of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - James D. Blakemore
- Department
of Chemistry, University of Kansas, 1251 Wescoe Hall Drive, 2010 Malott
Hall, Lawrence, Kansas 66045, United States
- Department
of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Sara M. Hashmi
- Department
of Chemical and Environmental Engineering, Yale University, 9 Hillhouse
Avenue, New Haven, Connecticut 06520, United States
| | - Robert H. Crabtree
- Department
of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
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20
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Vinyard DJ, Khan S, Brudvig GW. Photosynthetic water oxidation: binding and activation of substrate waters for O-O bond formation. Faraday Discuss 2016; 185:37-50. [PMID: 26447686 DOI: 10.1039/c5fd00087d] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Photosynthetic water oxidation occurs at the oxygen-evolving complex (OEC) of Photosystem II (PSII). The OEC, which contains a Mn4CaO5 inorganic cluster ligated by oxides, waters and amino-acid residues, cycles through five redox intermediates known as S(i) states (i = 0-4). The electronic and structural properties of the transient S4 intermediate that forms the O-O bond are not well understood. In order to gain insight into how water is activated for O-O bond formation in the S4 intermediate, we have performed a detailed analysis of S-state dependent substrate water binding kinetics taking into consideration data from Mn coordination complexes. This analysis supports a model in which the substrate waters are both bound as terminal ligands and react via a water-nucleophile attack mechanism.
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Affiliation(s)
- David J Vinyard
- Department of Chemistry, Yale University, New Haven, CT, United States.
| | - Sahr Khan
- Department of Chemistry, Yale University, New Haven, CT, United States.
| | - Gary W Brudvig
- Department of Chemistry, Yale University, New Haven, CT, United States.
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21
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Vinyard DJ, Askerka M, Debus RJ, Batista VS, Brudvig GW. Ammonia Binding in the Second Coordination Sphere of the Oxygen-Evolving Complex of Photosystem II. Biochemistry 2016; 55:4432-6. [DOI: 10.1021/acs.biochem.6b00543] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- David J. Vinyard
- Department
of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Mikhail Askerka
- Department
of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Richard J. Debus
- Department
of Biochemistry, University of California, Riverside, California 92521, United States
| | - Victor S. Batista
- Department
of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Gary W. Brudvig
- Department
of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
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22
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Vinyard DJ, Sun JS, Gimpel J, Ananyev GM, Mayfield SP, Charles Dismukes G. Natural isoforms of the Photosystem II D1 subunit differ in photoassembly efficiency of the water-oxidizing complex. Photosynth Res 2016; 128:141-150. [PMID: 26687161 DOI: 10.1007/s11120-015-0208-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 11/23/2015] [Indexed: 06/05/2023]
Abstract
Oxygenic photosynthesis efficiency at increasing solar flux is limited by light-induced damage (photoinhibition) of Photosystem II (PSII), primarily targeting the D1 reaction center subunit. Some cyanobacteria contain two natural isoforms of D1 that function better under low light (D1:1) or high light (D1:2). Herein, rates and yields of photoassembly of the Mn4CaO5 water-oxidizing complex (WOC) from the free inorganic cofactors (Mn(2+), Ca(2+), water, electron acceptor) and apo-WOC-PSII are shown to differ significantly: D1:1 apo-WOC-PSII exhibits a 2.3-fold faster rate-limiting step of photoassembly and up to seven-fold faster rate to the first light-stable Mn(3+) intermediate, IM1*, but with a much higher rate of photoinhibition than D1:2. Conversely, D1:2 apo-WOC-PSII assembles slower but has up to seven-fold higher yield, achieved by a higher quantum yield of charge separation and slower photoinhibition rate. These results confirm and extend previous observations of the two holoenzymes: D1:2-PSII has a greater quantum yield of primary charge separation, faster [P680 (+) Q A (-) ] charge recombination and less photoinhibition that results in a slower rate and higher yield of photoassembly of its apo-WOC-PSII complex. In contrast, D1:1-PSII has a lower quantum yield of primary charge separation, a slower [P680 (+) Q A (-) ] charge recombination rate, and faster photoinhibition that together result in higher rate but lower yield of photoassembly at higher light intensities. Cyanobacterial PSII reaction centers that contain the high- and low-light D1 isoforms can tailor performance to optimize photosynthesis at varying light conditions, with similar consequences on their photoassembly kinetics and yield. These different efficiencies of photoassembly versus photoinhibition impose differential costs for biosynthesis as a function of light intensity.
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Affiliation(s)
- David J Vinyard
- Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, 190 Frelinghuysen Rd., Piscataway, NJ, 08854, USA
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA
- Department of Chemistry, Yale University, New Haven, CT, 06520, USA
| | - Jennifer S Sun
- Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, 190 Frelinghuysen Rd., Piscataway, NJ, 08854, USA
- Department of Molecular, Cellular, and Development Biology, Yale University, New Haven, CT, 06520, USA
| | - Javier Gimpel
- San Diego Center for Algae Biotechnology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA, 92093, USA
- Centre for Biotechnology and Bioengineering, Universidad de Chile, Santiago, Chile
| | - Gennady M Ananyev
- Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, 190 Frelinghuysen Rd., Piscataway, NJ, 08854, USA
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Stephen P Mayfield
- San Diego Center for Algae Biotechnology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA, 92093, USA
| | - G Charles Dismukes
- Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, 190 Frelinghuysen Rd., Piscataway, NJ, 08854, USA.
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA.
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23
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Askerka M, Wang J, Vinyard DJ, Brudvig GW, Batista VS. S3 State of the O2-Evolving Complex of Photosystem II: Insights from QM/MM, EXAFS, and Femtosecond X-ray Diffraction. Biochemistry 2016; 55:981-4. [DOI: 10.1021/acs.biochem.6b00041] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mikhail Askerka
- Department of Chemistry and ‡Department of
Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Jimin Wang
- Department of Chemistry and ‡Department of
Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - David J. Vinyard
- Department of Chemistry and ‡Department of
Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Gary W. Brudvig
- Department of Chemistry and ‡Department of
Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Victor S. Batista
- Department of Chemistry and ‡Department of
Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520-8107, United States
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24
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Sinha SB, Shopov DY, Sharninghausen LS, Vinyard DJ, Mercado BQ, Brudvig GW, Crabtree RH. A Stable Coordination Complex of Rh(IV) in an N,O-Donor Environment. J Am Chem Soc 2015; 137:15692-5. [PMID: 26641941 DOI: 10.1021/jacs.5b12148] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
We describe facial and meridional isomers of [Rh(III)(pyalk)3], as well as meridional [Rh(IV)(pyalk)3](+) {pyalk =2-(2-pyridyl)-2-propanoate}, the first coordination complex in an N,O-donor environment to show a clean, reversible Rh(III/IV) redox couple and to have a stable Rh(IV) form, which we characterize by EPR and UV-visible spectroscopy as well as X-ray crystallography. The unprecedented stability of the Rh(IV) species is ascribed to the exceptional donor strength of the ligands, their oxidation resistance, and the meridional coordination geometry.
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Affiliation(s)
- Shashi B Sinha
- Department of Chemistry, Yale University , 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Dimitar Y Shopov
- Department of Chemistry, Yale University , 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Liam S Sharninghausen
- Department of Chemistry, Yale University , 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - David J Vinyard
- Department of Chemistry, Yale University , 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Brandon Q Mercado
- Department of Chemistry, Yale University , 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Gary W Brudvig
- Department of Chemistry, Yale University , 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Robert H Crabtree
- Department of Chemistry, Yale University , 225 Prospect Street, New Haven, Connecticut 06520, United States
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25
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Kraehling JR, Hao Z, Lee MY, Vinyard DJ, Velazquez H, Liu X, Stan RV, Brudvig GW, Sessa WC. Uncoupling Caveolae From Intracellular Signaling In Vivo. Circ Res 2015; 118:48-55. [PMID: 26602865 DOI: 10.1161/circresaha.115.307767] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 11/24/2015] [Indexed: 11/16/2022]
Abstract
RATIONALE Caveolin-1 (Cav-1) negatively regulates endothelial nitric oxide (NO) synthase-derived NO production, and this has been mapped to several residues on Cav-1, including F92. Herein, we reasoned that endothelial expression of an F92ACav-1 transgene would let us decipher the mechanisms and relationships between caveolae structure and intracellular signaling. OBJECTIVE This study was designed to separate caveolae formation from its downstream signaling effects. METHODS AND RESULTS An endothelial-specific doxycycline-regulated mouse model for the expression of Cav-1-F92A was developed. Blood pressure by telemetry and nitric oxide bioavailability by electron paramagnetic resonance and phosphorylation of vasodilator-stimulated phosphoprotein were determined. Caveolae integrity in the presence of Cav-1-F92A was measured by stabilization of caveolin-2, sucrose gradient, and electron microscopy. Histological analysis of heart and lung, echocardiography, and signaling were performed. CONCLUSIONS This study shows that mutant Cav-1-F92A forms caveolae structures similar to WT but leads to increases in NO bioavailability in vivo, thereby demonstrating that caveolae formation and downstream signaling events occur through independent mechanisms.
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Affiliation(s)
- Jan R Kraehling
- From the Vascular Biology and Therapeutics Program (J.R.K., Z.H., M.Y.L., W.C.S.) and Department of Pharmacology (J.R.K., Z.H., M.Y.L., W.C.S.), Yale University School of Medicine, New Haven, CT; Department of Chemistry, Yale University, New Haven, CT (D.J.V., G.W.B.); Department of Internal Medicine, VA Connecticut Healthcare System, West Haven, CT (H.V.); Department of Cell Biology, Yale University, School of Medicine, New Haven, CT (X.L.); and Department of Pathology, Dartmouth Medical School, Lebanon, NH (R.V.S.)
| | - Zhengrong Hao
- From the Vascular Biology and Therapeutics Program (J.R.K., Z.H., M.Y.L., W.C.S.) and Department of Pharmacology (J.R.K., Z.H., M.Y.L., W.C.S.), Yale University School of Medicine, New Haven, CT; Department of Chemistry, Yale University, New Haven, CT (D.J.V., G.W.B.); Department of Internal Medicine, VA Connecticut Healthcare System, West Haven, CT (H.V.); Department of Cell Biology, Yale University, School of Medicine, New Haven, CT (X.L.); and Department of Pathology, Dartmouth Medical School, Lebanon, NH (R.V.S.)
| | - Monica Y Lee
- From the Vascular Biology and Therapeutics Program (J.R.K., Z.H., M.Y.L., W.C.S.) and Department of Pharmacology (J.R.K., Z.H., M.Y.L., W.C.S.), Yale University School of Medicine, New Haven, CT; Department of Chemistry, Yale University, New Haven, CT (D.J.V., G.W.B.); Department of Internal Medicine, VA Connecticut Healthcare System, West Haven, CT (H.V.); Department of Cell Biology, Yale University, School of Medicine, New Haven, CT (X.L.); and Department of Pathology, Dartmouth Medical School, Lebanon, NH (R.V.S.)
| | - David J Vinyard
- From the Vascular Biology and Therapeutics Program (J.R.K., Z.H., M.Y.L., W.C.S.) and Department of Pharmacology (J.R.K., Z.H., M.Y.L., W.C.S.), Yale University School of Medicine, New Haven, CT; Department of Chemistry, Yale University, New Haven, CT (D.J.V., G.W.B.); Department of Internal Medicine, VA Connecticut Healthcare System, West Haven, CT (H.V.); Department of Cell Biology, Yale University, School of Medicine, New Haven, CT (X.L.); and Department of Pathology, Dartmouth Medical School, Lebanon, NH (R.V.S.)
| | - Heino Velazquez
- From the Vascular Biology and Therapeutics Program (J.R.K., Z.H., M.Y.L., W.C.S.) and Department of Pharmacology (J.R.K., Z.H., M.Y.L., W.C.S.), Yale University School of Medicine, New Haven, CT; Department of Chemistry, Yale University, New Haven, CT (D.J.V., G.W.B.); Department of Internal Medicine, VA Connecticut Healthcare System, West Haven, CT (H.V.); Department of Cell Biology, Yale University, School of Medicine, New Haven, CT (X.L.); and Department of Pathology, Dartmouth Medical School, Lebanon, NH (R.V.S.)
| | - Xinran Liu
- From the Vascular Biology and Therapeutics Program (J.R.K., Z.H., M.Y.L., W.C.S.) and Department of Pharmacology (J.R.K., Z.H., M.Y.L., W.C.S.), Yale University School of Medicine, New Haven, CT; Department of Chemistry, Yale University, New Haven, CT (D.J.V., G.W.B.); Department of Internal Medicine, VA Connecticut Healthcare System, West Haven, CT (H.V.); Department of Cell Biology, Yale University, School of Medicine, New Haven, CT (X.L.); and Department of Pathology, Dartmouth Medical School, Lebanon, NH (R.V.S.)
| | - Radu V Stan
- From the Vascular Biology and Therapeutics Program (J.R.K., Z.H., M.Y.L., W.C.S.) and Department of Pharmacology (J.R.K., Z.H., M.Y.L., W.C.S.), Yale University School of Medicine, New Haven, CT; Department of Chemistry, Yale University, New Haven, CT (D.J.V., G.W.B.); Department of Internal Medicine, VA Connecticut Healthcare System, West Haven, CT (H.V.); Department of Cell Biology, Yale University, School of Medicine, New Haven, CT (X.L.); and Department of Pathology, Dartmouth Medical School, Lebanon, NH (R.V.S.)
| | - Gary W Brudvig
- From the Vascular Biology and Therapeutics Program (J.R.K., Z.H., M.Y.L., W.C.S.) and Department of Pharmacology (J.R.K., Z.H., M.Y.L., W.C.S.), Yale University School of Medicine, New Haven, CT; Department of Chemistry, Yale University, New Haven, CT (D.J.V., G.W.B.); Department of Internal Medicine, VA Connecticut Healthcare System, West Haven, CT (H.V.); Department of Cell Biology, Yale University, School of Medicine, New Haven, CT (X.L.); and Department of Pathology, Dartmouth Medical School, Lebanon, NH (R.V.S.)
| | - William C Sessa
- From the Vascular Biology and Therapeutics Program (J.R.K., Z.H., M.Y.L., W.C.S.) and Department of Pharmacology (J.R.K., Z.H., M.Y.L., W.C.S.), Yale University School of Medicine, New Haven, CT; Department of Chemistry, Yale University, New Haven, CT (D.J.V., G.W.B.); Department of Internal Medicine, VA Connecticut Healthcare System, West Haven, CT (H.V.); Department of Cell Biology, Yale University, School of Medicine, New Haven, CT (X.L.); and Department of Pathology, Dartmouth Medical School, Lebanon, NH (R.V.S.)
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Guard LM, Mohadjer Beromi M, Brudvig GW, Hazari N, Vinyard DJ. Comparison of dppf‐Supported Nickel Precatalysts for the Suzuki–Miyaura Reaction: The Observation and Activity of Nickel(I). Angew Chem Int Ed Engl 2015; 54:13352-6. [DOI: 10.1002/anie.201505699] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2015] [Indexed: 11/11/2022]
Affiliation(s)
- Louise M. Guard
- The Department of Chemistry, Yale University, P.O. Box 208107, New Haven, CT 06520 (USA)
| | - Megan Mohadjer Beromi
- The Department of Chemistry, Yale University, P.O. Box 208107, New Haven, CT 06520 (USA)
| | - Gary W. Brudvig
- The Department of Chemistry, Yale University, P.O. Box 208107, New Haven, CT 06520 (USA)
| | - Nilay Hazari
- The Department of Chemistry, Yale University, P.O. Box 208107, New Haven, CT 06520 (USA)
| | - David J. Vinyard
- The Department of Chemistry, Yale University, P.O. Box 208107, New Haven, CT 06520 (USA)
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Abstract
Nitrogenases are the enzymes by which certain microorganisms convert atmospheric dinitrogen (N2) to ammonia, thereby providing essential nitrogen atoms for higher organisms. The most common nitrogenases reduce atmospheric N2 at the FeMo cofactor, a sulfur-rich iron-molybdenum cluster (FeMoco). The central iron sites that are coordinated to sulfur and carbon atoms in FeMoco have been proposed to be the substrate binding sites, on the basis of kinetic and spectroscopic studies. In the resting state, the central iron sites each have bonds to three sulfur atoms and one carbon atom. Addition of electrons to the resting state causes the FeMoco to react with N2, but the geometry and bonding environment of N2-bound species remain unknown. Here we describe a synthetic complex with a sulfur-rich coordination sphere that, upon reduction, breaks an Fe-S bond and binds N2. The product is the first synthetic Fe-N2 complex in which iron has bonds to sulfur and carbon atoms, providing a model for N2 coordination in the FeMoco. Our results demonstrate that breaking an Fe-S bond is a chemically reasonable route to N2 binding in the FeMoco, and show structural and spectroscopic details for weakened N2 on a sulfur-rich iron site.
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Affiliation(s)
- Ilija Čorić
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, USA
| | - Brandon Q Mercado
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, USA
| | - Eckhard Bill
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - David J Vinyard
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, USA
| | - Patrick L Holland
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, USA
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28
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Askerka M, Vinyard DJ, Brudvig GW, Batista VS. NH3 Binding to the S2 State of the O2-Evolving Complex of Photosystem II: Analogue to H2O Binding during the S2 → S3 Transition. Biochemistry 2015; 54:5783-6. [DOI: 10.1021/acs.biochem.5b00974] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Mikhail Askerka
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - David J. Vinyard
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Gary W. Brudvig
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Victor S. Batista
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
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29
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Guard LM, Mohadjer Beromi M, Brudvig GW, Hazari N, Vinyard DJ. Comparison of dppf‐Supported Nickel Precatalysts for the Suzuki–Miyaura Reaction: The Observation and Activity of Nickel(I). Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201505699] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Louise M. Guard
- The Department of Chemistry, Yale University, P.O. Box 208107, New Haven, CT 06520 (USA)
| | - Megan Mohadjer Beromi
- The Department of Chemistry, Yale University, P.O. Box 208107, New Haven, CT 06520 (USA)
| | - Gary W. Brudvig
- The Department of Chemistry, Yale University, P.O. Box 208107, New Haven, CT 06520 (USA)
| | - Nilay Hazari
- The Department of Chemistry, Yale University, P.O. Box 208107, New Haven, CT 06520 (USA)
| | - David J. Vinyard
- The Department of Chemistry, Yale University, P.O. Box 208107, New Haven, CT 06520 (USA)
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30
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Branchini BR, Behney CE, Southworth TL, Fontaine DM, Gulick AM, Vinyard DJ, Brudvig GW. Experimental Support for a Single Electron-Transfer Oxidation Mechanism in Firefly Bioluminescence. J Am Chem Soc 2015; 137:7592-5. [PMID: 26057379 DOI: 10.1021/jacs.5b03820] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Firefly luciferase produces light by converting substrate beetle luciferin into the corresponding adenylate that it subsequently oxidizes to oxyluciferin, the emitter of bioluminescence. We have confirmed the generally held notions that the oxidation step is initiated by formation of a carbanion intermediate and that a hydroperoxide (anion) is involved. Additionally, structural evidence is presented that accounts for the delivery of oxygen to the substrate reaction site. Herein, we report key convincing spectroscopic evidence of the participation of superoxide anion in a related chemical model reaction that supports a single electron-transfer pathway for the critical oxidative process. This mechanism may be a common feature of bioluminescence processes in which light is produced by an enzyme in the absence of cofactors.
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Affiliation(s)
- Bruce R Branchini
- †Department of Chemistry, Connecticut College, New London, Connecticut 06320, United States
| | - Curran E Behney
- †Department of Chemistry, Connecticut College, New London, Connecticut 06320, United States
| | - Tara L Southworth
- †Department of Chemistry, Connecticut College, New London, Connecticut 06320, United States
| | - Danielle M Fontaine
- †Department of Chemistry, Connecticut College, New London, Connecticut 06320, United States
| | - Andrew M Gulick
- §Hauptman-Woodward Institute, Buffalo, New York 14203, United States.,∥Department of Structural Biology, University of Buffalo, Buffalo, New York 14203, United States
| | - David J Vinyard
- ‡Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Gary W Brudvig
- ‡Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
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31
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Vogt L, Vinyard DJ, Khan S, Brudvig GW. Oxygen-evolving complex of Photosystem II: an analysis of second-shell residues and hydrogen-bonding networks. Curr Opin Chem Biol 2015; 25:152-8. [DOI: 10.1016/j.cbpa.2014.12.040] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 12/20/2014] [Accepted: 12/25/2014] [Indexed: 12/22/2022]
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Krishnan A, Kumaraswamy GK, Vinyard DJ, Gu H, Ananyev G, Posewitz MC, Dismukes GC. Metabolic and photosynthetic consequences of blocking starch biosynthesis in the green alga Chlamydomonas reinhardtii sta6 mutant. Plant J 2015; 81:947-60. [PMID: 25645872 DOI: 10.1111/tpj.12783] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 01/20/2015] [Accepted: 01/21/2015] [Indexed: 05/20/2023]
Abstract
Upon nutrient deprivation, microalgae partition photosynthate into starch and lipids at the expense of protein synthesis and growth. We investigated the role of starch biosynthesis with respect to photosynthetic growth and carbon partitioning in the Chlamydomonas reinhardtii starchless mutant, sta6, which lacks ADP-glucose pyrophosphorylase. This mutant is unable to convert glucose-1-phosphate to ADP-glucose, the precursor of starch biosynthesis. During nutrient-replete culturing, sta6 does not re-direct metabolism to make more proteins or lipids, and accumulates 20% less biomass. The underlying molecular basis for the decreased biomass phenotype was identified using LC-MS metabolomics studies and flux methods. Above a threshold light intensity, photosynthetic electron transport rates (water → CO2) decrease in sta6 due to attenuated rates of NADPH re-oxidation, without affecting photosystems I or II (no change in isolated photosynthetic electron transport). We observed large accumulations of carbon metabolites that are precursors for the biosynthesis of lipids, amino acids and sugars/starch, indicating system-wide consequences of slower NADPH re-oxidation. Attenuated carbon fixation resulted in imbalances in both redox and adenylate energy. The pool sizes of both pyridine and adenylate nucleotides in sta6 increased substantially to compensate for the slower rate of turnover. Mitochondrial respiration partially relieved the reductant stress; however, prolonged high-light exposure caused accelerated photoinhibition. Thus, starch biosynthesis in Chlamydomonas plays a critical role as a principal carbon sink influencing cellular energy balance however, disrupting starch biosynthesis does not redirect resources to other bioproducts (lipids or proteins) during nutrient-replete culturing, resulting in cells that are susceptible to photochemical damage caused by redox stress.
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Affiliation(s)
- Anagha Krishnan
- Waksman Institute of Microbiology, Rutgers: The State University of New Jersey, Piscataway, NJ, 08854, USA
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33
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Askerka M, Vinyard DJ, Wang J, Brudvig GW, Batista VS. Analysis of the Radiation-Damage-Free X-ray Structure of Photosystem II in Light of EXAFS and QM/MM Data. Biochemistry 2015; 54:1713-6. [DOI: 10.1021/acs.biochem.5b00089] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Mikhail Askerka
- Department
of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States,
| | - David J. Vinyard
- Department
of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States,
| | - Jimin Wang
- Department
of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520-8114, United States
| | - Gary W. Brudvig
- Department
of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States,
| | - Victor S. Batista
- Department
of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States,
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Vinyard DJ, Brudvig GW. Insights into substrate binding to the oxygen-evolving complex of photosystem II from ammonia inhibition studies. Biochemistry 2015; 54:622-8. [PMID: 25531753 DOI: 10.1021/bi5014134] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Water oxidation in Photosystem II occurs at the oxygen-evolving complex (OEC), which cycles through distinct intermediates, S0-S4. The inhibitor ammonia selectively binds to the S2 state at an unresolved site that is not competitive with substrate water. By monitoring the yields of flash-induced oxygen production, we show that ammonia decreases the net efficiency of OEC turnover and slows the decay kinetics of S2 to S1. The temperature dependence of biphasic S2 decay kinetics provides activation energies that do not vary in control and ammonia conditions. We interpret our data in the broader context of previous studies by introducing a kinetic model for both the formation and decay of ammonia-bound S2. The model predicts ammonia binds to S2 rapidly (t1/2 = 1 ms) with a large equilibrium constant. This finding implies that ammonia decreases the reduction potential of S2 by at least 2.7 kcal mol(-1) (>120 mV), which is not consistent with ammonia substitution of a terminal water ligand of Mn(IV). Instead, these data support the proposal that ammonia binds as a bridging ligand between two Mn atoms. Implications for the mechanism of O-O bond formation are discussed.
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Affiliation(s)
- David J Vinyard
- Department of Chemistry, Yale University , New Haven, Connecticut 06520-8107, United States
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Abstract
The six-electron oxidation of two nitrides to N2 is a key step of ammonia synthesis and decomposition reactions on surfaces. In molecular complexes, nitride coupling has been observed with terminal nitrides, but not with bridging nitride complexes that more closely resemble catalytically important surface species. Further, nitride coupling has not been reported in systems where the nitrides are derived from N2. Here, we show that a molecular diiron(II) diiron(III) bis(nitride) complex reacts with Lewis bases, leading to the rapid six-electron oxidation of two bridging nitrides to form N2. Surprisingly, these mild reagents generate high yields of iron(I) products from the iron(II/III) starting material. This is the first molecular system that both breaks and forms the triple bond of N2 at room temperature. These results highlight the ability of multi-iron species to decrease the energy barriers associated with the activation of strong bonds.
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Affiliation(s)
- K Cory MacLeod
- Department of Chemistry, Yale University , 225 Prospect Street, New Haven, Connecticut 06520, United States
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36
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Vinyard DJ, Gimpel J, Ananyev GM, Mayfield SP, Dismukes GC. Engineered Photosystem II reaction centers optimize photochemistry versus photoprotection at different solar intensities. J Am Chem Soc 2014; 136:4048-55. [PMID: 24548276 DOI: 10.1021/ja5002967] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The D1 protein of Photosystem II (PSII) provides most of the ligating amino acid residues for the Mn4CaO5 water-oxidizing complex (WOC) and half of the reaction center cofactors, and it is present as two isoforms in the cyanobacterium Synechococcus elongatus PCC 7942. These isoforms, D1:1 and D1:2, confer functional advantages for photosynthetic growth at low and high light intensities, respectively. D1:1, D1:2, and seven point mutations in the D1:2 background that are native to D1:1 were expressed in the green alga Chlamydomonas reinhardtii. We used these nine strains to show that those strains that confer a higher yield of PSII charge separation under light-limiting conditions (where charge recombination is significant) have less efficient photochemical turnover, measured in terms of both a lower WOC turnover probability and a longer WOC cycle period. Conversely, these same strains under light saturation (where charge recombination does not compete) confer a correspondingly faster O2 evolution rate and greater protection against photoinhibition. Taken together, the data clearly establish that PSII primary charge separation is a trade-off between photochemical productivity (water oxidation and plastoquinone reduction) and charge recombination (photoprotection). These trade-offs add up to a significant growth advantage for the two natural isoforms. These insights provide fundamental design principles for engineering of PSII reaction centers with optimal photochemical efficiencies for growth at low versus high light intensities.
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Affiliation(s)
- David J Vinyard
- Department of Chemistry and Chemical Biology and ‡Waksman Institute of Microbiology, Rutgers, The State University of New Jersey , Piscataway, New Jersey 08854, United States
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Affiliation(s)
- David J. Vinyard
- Department of Chemistry and Chemical Biology and the Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854; ,
- Department of Chemistry, Princeton University, Princeton, New Jersey 08540;
| | - Gennady M. Ananyev
- Department of Chemistry and Chemical Biology and the Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854; ,
| | - G. Charles Dismukes
- Department of Chemistry and Chemical Biology and the Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854; ,
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38
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Vinyard DJ, Gimpel J, Ananyev GM, Cornejo MA, Golden SS, Mayfield SP, Dismukes GC. Natural variants of photosystem II subunit D1 tune photochemical fitness to solar intensity. J Biol Chem 2012; 288:5451-62. [PMID: 23271739 DOI: 10.1074/jbc.m112.394668] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Photosystem II (PSII) is composed of six core polypeptides that make up the minimal unit capable of performing the primary photochemistry of light-driven charge separation and water oxidation in all oxygenic phototrophs. The D1 subunit of this complex contains most of the ligating amino acid residues for the Mn(4)CaO(5) core of the water-oxidizing complex (WOC). Most cyanobacteria have 3-5 copies of the psbA gene coding for at least two isoforms of D1, whereas algae and plants have only one isoform. Synechococcus elongatus PCC 7942 contains two D1 isoforms; D1:1 is expressed under low light conditions, and D1:2 is up-regulated in high light or stress conditions. Using a heterologous psbA expression system in the green alga Chlamydomonas reinhardtii, we have measured growth rate, WOC cycle efficiency, and O(2) yield as a function of D1:1, D1:2, or the native algal D1 isoform. D1:1-PSII cells outcompete D1:2-PSII cells and accumulate more biomass in light-limiting conditions. However, D1:2-PSII cells easily outcompete D1:1-PSII cells at high light intensities. The native C. reinhardtii-PSII WOC cycles less efficiently at all light intensities and produces less O(2) than either cyanobacterial D1 isoform. D1:2-PSII makes more O(2) per saturating flash than D1:1-PSII, but it exhibits lower WOC cycling efficiency at low light intensities due to a 40% faster charge recombination rate in the S(3) state. These functional advantages of D1:1-PSII and D1:2-PSII at low and high light regimes, respectively, can be explained by differences in predicted redox potentials of PSII electron acceptors that control kinetic performance.
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Affiliation(s)
- David J Vinyard
- Department of Chemistry and Chemical Biology, State University of New Jersey, Piscataway, New Jersey 08854, USA
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Nguyen TA, Brescic J, Vinyard DJ, Chandrasekar T, Dismukes GC. Identification of an oxygenic reaction center psbADC operon in the cyanobacterium Gloeobacter violaceus PCC 7421. Mol Biol Evol 2011; 29:35-8. [PMID: 21903678 DOI: 10.1093/molbev/msr224] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Gloeobacter violaceus, the earliest diverging oxyphotobacterium (cyanobacterium) on the 16S ribosomal RNA tree, has five copies of the photosystem II psbA gene encoding the D1 reaction center protein subunit. These copies are widely distributed throughout the 4.6 Mbp genome with only one copy colocalizing with other PSII subunits, in marked contrast to all other psbA genes in all publicly available sequenced genomes. A clustering of two other psb genes around psbA3 (glr2322) is unique to Gloeobacter. We provide experimental proof for the transcription of a psbA3DC operon, encoding three of the five reaction center core subunits (D1, D2, and CP43). This is the first example of a transcribed gene cluster containing the D1/D2 or D1/D2/CP43 subunits of PSII in an oxygenic phototroph (prokaryotic or eukaryotic). Implications for the evolution of oxygenic photosynthesis are discussed.
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40
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Vinyard DJ, Su S, Richter MM. Electrogenerated Chemiluminescence of 9,10-Diphenylanthracene, Rubrene, and Anthracene in Fluorinated Aromatic Solvents. J Phys Chem A 2008; 112:8529-33. [DOI: 10.1021/jp804418f] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- David J. Vinyard
- Department of Chemistry, Missouri State University, Springfield, Missouri 65897
| | - Shujun Su
- Department of Chemistry, Missouri State University, Springfield, Missouri 65897
| | - Mark M. Richter
- Department of Chemistry, Missouri State University, Springfield, Missouri 65897
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Abstract
The electrochemistry, UV-vis absorption, photoluminescence (PL), and coreactant electrogenerated chemiluminescence (ECL) of Ru(bpy)3(2+) (where bpy=2,2'-bipyridine) have been obtained in a series of hydroxylic solvents. The solvents included fluorinated and nonfluorinated alcohols and alcohol/water mixtures. Tri-n-propylamine was used as the oxidative-reductive ECL coreactant. Blue shifts of up to 30 nm in PL emission wavelength maximums are observed compared to a Ru(bpy)3(2+)/H2O standard due to interactions of the polar excited state (i.e., *Ru(bpy)3(2+)) with the solvent media. For example, Ru(bpy)3(2+) in water has an emission maximum of 599 nm while in the more polar hexafluoropropanol and trifluoroethanol it is 562 and 571 nm, respectively. ECL spectra are similar to PL spectra, indicating the same excited state is formed in both experiments. The difference between the electrochemically reversible oxidation (Ru(bpy)3(2+/3+)) and first reduction (Ru(bpy)2(2+/1+)) correlates well with the energy gap observed in the luminescence experiments. Although the ECL is linear in all solvents with [Ru(bpy)3(2+)] ranging from 100 to 0.1 nm, little correlation between the polarity of the solvent and the ECL efficiency (phiecl=number of photons per redox event) was observed. However, dramatic increases in phiecl ranging from 6- to 270-fold were seen in mixed alcohol/water solutions.
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Affiliation(s)
- David J Vinyard
- Department of Chemistry, Missouri State University, Springfield, Missouri 65897, USA
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42
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Vinyard DJ, Swavey S, Richter MM. Photoluminescence and electrogenerated chemiluminescence of a bis(bipyridyl)ruthenium(II)–porphyrin complex. Inorganica Chim Acta 2007. [DOI: 10.1016/j.ica.2006.08.032] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Vinyard DJ, Richter MM. Electrogenerated chemiluminescence of the lithium salts of 8-hydroxyquinoline and 2-methyl-8-hydroxyquinoline. Dalton Trans 2006:4461-4. [PMID: 16981020 DOI: 10.1039/b608145b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The spectroscopy, electrochemistry, and electrogenerated chemiluminescence (ECL) of [(q)(qH)Li]x (qH=8-hydroxyquinolinato) and [(Meq)(MeqH)Li]x (MeQH=2-methyl-8-hydroxyquinolinato) have been investigated. In both acetonitrile and aqueous solutions, [(q)(qH)Li]x and [(Meq)(MeqH)Li]x have absorption maxima at 320 and 309 nm, respectively. When excited at these wavelengths, the complexes emit around 500 nm (blue-green) in acetonitrile. Photoluminescence efficiencies (phiem) were 0.036 for [(q)(qH)Li]x and 0.012 for [(Meq)(MeqH)Li]x when compared to Ru(bpy)3(2+) (bpy=2,2'-bipyridine) with phiem=0.042. No photoluminescence was observed in aqueous media. The complexes show irreversible oxidative electrochemistry and quasi-reversible reductions in acetonitrile. ECL efficiencies (phiecl) were 0.097 for [(q)(qH)Li]x and 0.080 for [(Meq)(MeqH)Li]x when compared to Ru(bpy)(3)2+ (phiecl=1) in aqueous buffered solution and 0.035 for [(q)(qH)Li]x and 0.028 for [(Meq)(MeqH)Li]x in acetonitrile (0.05 M tri-n-propylamine (TPrA) as an oxidative-reductive ECL co-reactant). The ECL peaks at a potential corresponding to oxidation of both the TPrA and [(q)(qH)Li]x or [(Meq)(MeqH)Li]x. Also, qualitative studies using transmission filters suggest that both complexes emit ECL in approximately the same blue-green region as their photoluminescence, indicating that the same excited state is formed in both experiments.
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Affiliation(s)
- David J Vinyard
- Department of Chemistry, Missouri State University, Springfield, Missouri 65897, USA
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