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Tong X, Kim EJ, Lee JK. Sustainability of in vitro light-dependent NADPH generation by the thylakoid membrane of Synechocystis sp. PCC6803. Microb Cell Fact 2022; 21:94. [PMID: 35643504 PMCID: PMC9148488 DOI: 10.1186/s12934-022-01825-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Accepted: 05/15/2022] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND NADPH is used as a reductant in various biosynthetic reactions. Cell-free bio-systems have gained considerable attention owing to their high energy utilization and time efficiency. Efforts have been made to continuously supply reducing power to the reaction mixture in a cyclical manner. The thylakoid membrane (TM) is a promising molecular energy generator, producing NADPH under light. Thus, TM sustainability is of major relevance for its in vitro utilization. RESULTS Over 70% of TMs prepared from Synechocystis sp. PCC6803 existed in a sealed vesicular structure, with the F1 complex of ATP synthase facing outward (right-side-out), producing NADPH and ATP under light. The NADPH generation activity of TM increased approximately two-fold with the addition of carbonyl cyanide-p-(trifluoromethoxy) phenylhydrazone (FCCP) or removal of the F1 complex using EDTA. Thus, the uncoupling of proton translocation from the electron transport chain or proton leakage through the Fo complex resulted in greater NADPH generation. Biosilicified TM retained more than 80% of its NADPH generation activity after a week at 30°C in the dark. However, activity declined sharply to below 30% after two days in light. The introduction of engineered water-forming NADPH oxidase (Noxm) to keep the electron transport chain of TM working resulted in the improved sustainability of NADPH generation activity in a ratio (Noxm to TM)-dependent manner, which correlated with the decrease of singlet oxygen generation. Removal of reactive oxygen species (ROS) by catalase further highlighted the sustainable NADPH generation activity of up to 80% in two days under light. CONCLUSION Reducing power generated by light energy has to be consumed for TM sustainability. Otherwise, TM can generate singlet oxygen, causing oxidative damage. Thus, TMs should be kept in the dark when not in use. Although NADPH generation activity by TM can be extended via silica encapsulation, further removal of hydrogen peroxide results in an improvement of TM sustainability. Therefore, as long as ROS formation by TM in light is properly handled, it can be used as a promising source of reducing power for in vitro biochemical reactions.
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Affiliation(s)
- Xiaomeng Tong
- Department of Life Science, Sogang University, Mapo, Shinsu 1, Seoul, 121-742, Korea
| | - Eui-Jin Kim
- Microbial Research Department, Nakdonggang National Institute of Biological Resources, Gyeongsangbuk-do, Sangju-si, 37242, Korea.
| | - Jeong K Lee
- Department of Life Science, Sogang University, Mapo, Shinsu 1, Seoul, 121-742, Korea.
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LRP6 transduces a canonical Wnt signal independently of Axin degradation by inhibiting GSK3's phosphorylation of beta-catenin. Proc Natl Acad Sci U S A 2008; 105:8032-7. [PMID: 18509060 DOI: 10.1073/pnas.0803025105] [Citation(s) in RCA: 158] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Wnt/beta-catenin signaling controls various cell fates in metazoan development and is misregulated in several cancers and developmental disorders. Binding of a Wnt ligand to its transmembrane coreceptors inhibits phosphorylation and degradation of the transcriptional coactivator beta-catenin, which then translocates to the nucleus to regulate target gene expression. To understand how Wnt signaling prevents beta-catenin degradation, we focused on the Wnt coreceptor low-density lipoprotein receptor-related protein 6 (LRP6), which is required for signal transduction and is sufficient to activate Wnt signaling when overexpressed. LRP6 has been proposed to stabilize beta-catenin by stimulating degradation of Axin, a scaffold protein required for beta-catenin degradation. In certain systems, however, Wnt-mediated Axin turnover is not detected until after beta-catenin has been stabilized. Thus, LRP6 may also signal through a mechanism distinct from Axin degradation. To establish a biochemically tractable system to test this hypothesis, we expressed and purified the LRP6 intracellular domain from bacteria and show that it promotes beta-catenin stabilization and Axin degradation in Xenopus egg extract. Using an Axin mutant that does not degrade in response to LRP6, we demonstrate that LRP6 can stabilize beta-catenin in the absence of Axin turnover. Through experiments in egg extract and reconstitution with purified proteins, we identify a mechanism whereby LRP6 stabilizes beta-catenin independently of Axin degradation by directly inhibiting GSK3's phosphorylation of beta-catenin.
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McCallum JR, McCarty RE. Proton flux through the chloroplast ATP synthase is altered by cleavage of its gamma subunit. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2007; 1767:974-9. [PMID: 17559799 DOI: 10.1016/j.bbabio.2007.04.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2007] [Revised: 04/02/2007] [Accepted: 04/23/2007] [Indexed: 11/21/2022]
Abstract
Electron transport, the proton gradient and ATP synthesis were determined in thylakoids that had been briefly exposed to a low concentration of trypsin during illumination. This treatment cleaves the gamma subunit of the ATP synthase into two large fragments that remain associated with the enzyme. Higher rates of electron transport are required to generate a given value of the proton gradient in the trypsin-treated membranes than in control membranes, indicating that the treated membranes are proton leaky. Since venturicidin restores electron transport and the proton gradient to control levels, the proton leak is through the ATP synthase. Remarkably, the synthesis of ATP by the trypsin-treated membranes at saturating light intensities is only slightly inhibited even though the proton gradient is significantly lower in the treated thylakoids. ATP synthesis and the proton gradient were determined as a function of light intensity in control and trypsin-treated thylakoids. The trypsin-treated membranes synthesized ATP at lower values of the proton gradient than the control membranes. Cleavage of the gamma subunit abrogates inhibition of the activity of the chloroplast ATP synthase by the epsilon subunit. Our results suggest that overcoming inhibition by the epsilon subunit costs energy.
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Affiliation(s)
- Jeremy R McCallum
- Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218, USA
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Samra HS, Gao F, He F, Hoang E, Chen Z, Gegenheimer PA, Berrie CL, Richter ML. Structural Analysis of the Regulatory Dithiol-containing Domain of the Chloroplast ATP Synthase γ Subunit. J Biol Chem 2006; 281:31041-9. [PMID: 16895914 DOI: 10.1074/jbc.m603315200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The gamma subunit of the F1 portion of the chloroplast ATP synthase contains a critically placed dithiol that provides a redox switch converting the enzyme from a latent to an active ATPase. The switch prevents depletion of intracellular ATP pools in the dark when photophosphorylation is inactive. The dithiol is located in a special regulatory segment of about 40 amino acids that is absent from the gamma subunits of the eubacterial and mitochondrial enzymes. Site-directed mutagenesis was used to probe the relationship between the structure of the gamma regulatory segment and its function in ATPase regulation via its interaction with the inhibitory epsilon subunit. Mutations were designed using a homology model of the chloroplast gamma subunit based on the analogous structures of the bacterial and mitochondrial homologues. The mutations included (a) substituting both of the disulfide-forming cysteines (Cys199 and Cys205) for alanines, (b) deleting nine residues containing the dithiol, (c) deleting the region distal to the dithiol (residues 224-240), and (d) deleting the entire segment between residues 196 and 241 with the exception of a small spacer element, and (e) deleting pieces from a small loop segment predicted by the model to interact with the dithiol domain. Deletions within the dithiol domain and within parts of the loop segment resulted in loss of redox control of the ATPase activity of the F1 enzyme. Deleting the distal segment, the whole regulatory domain, or parts of the loop segment had the additional effect of reducing the maximum extent of inhibition obtained upon adding the epsilon subunit but did not abolish epsilon binding. The results suggest a mechanism by which the gamma and epsilon subunits interact with each other to induce the latent state of the enzyme.
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Affiliation(s)
- Hardeep S Samra
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas 66045, USA
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Richter ML, Samra HS, He F, Giessel AJ, Kuczera KK. Coupling proton movement to ATP synthesis in the chloroplast ATP synthase. J Bioenerg Biomembr 2006; 37:467-73. [PMID: 16691485 DOI: 10.1007/s10863-005-9493-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The chloroplast F(0)F(1)-ATP synthase-ATPase is a tiny rotary motor responsible for coupling ATP synthesis and hydrolysis to the light-driven electrochemical proton gradient. Reversible oxidation/reduction of a dithiol, located within a special regulatory domain of the gamma subunit of the chloroplast F(1) enzyme, switches the enzyme between an inactive and an active state. This regulatory mechanism is unique to the ATP synthases of higher plants and its physiological significance lies in preventing nonproductive depletion of essential ATP pools in the dark. The three-dimensional structure of the chloroplast F(1) gamma subunit has not yet been solved. To examine the mechanism of dithiol regulation, a model of the chloroplast gamma subunit was obtained through segmental homology modeling based on the known structures of the mitochondrial and bacterial gamma subunits, together with de novo construction of the unknown regulatory domain. The model has provided considerable insight into how the dithiol might modulate catalytic function. This has, in turn, suggested a mechanism by which rotation of subunits in F(0), the transmembrane proton channel portion of the enzyme, can be coupled, via the epsilon subunit, to rotation of the gamma subunit of F(1) to achieve the 120 degrees (or 90 degrees +30 degrees) stepping action that is characteristic of F(1) gamma subunit rotation.
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Affiliation(s)
- Mark L Richter
- Departments of Chemistry and Molecular Biosciences, The University of Kansas, Lawrence, Kansas 66045, USA.
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6
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McCarty RE. ATP synthase of chloroplast thylakoid membranes: a more in depth characterization of its ATPase activity. J Bioenerg Biomembr 2006; 37:289-97. [PMID: 16341773 DOI: 10.1007/s10863-005-8640-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2005] [Accepted: 08/02/2005] [Indexed: 10/25/2022]
Abstract
In contrast to everted mitochondrial inner membrane vesicles and eubacterial plasma membrane vesicles, the ATPase activity of chloroplast ATP synthase in thylakoid membranes is extremely low. Several treatments of thylakoids that unmask ATPase activity are known. Illumination of thylakoids that contain reduced ATP synthase (reduced thylakoids) promotes the hydrolysis of ATP in the dark. Incubation of thylakoids with trypsin can also elicit higher rates of ATPase activity. In this paper the properties of the ATPase activity of the ATP synthase in thylakoids treated with trypsin are compared with those of the ATPase activity in reduced thylakoids. The trypsin-treated membranes have significant ATPase activity in the presence of Ca2+, whereas the Ca2+-ATPase activity of reduced thylakoids is very low. The Mg2+-ATPase activity of the trypsinized thylakoids was only partially inhibited by the uncouplers, at concentrations that fully inhibit the ATPase activity of reduced membranes. Incubation of reduced thylakoids with ADP in Tris buffer prior to assay abolishes Mg2+-ATPase activity. The Mg2+-ATPase activity of trypsin-treated thylakoids was unaffected by incubation with ADP. Trypsin-treated membranes can make ATP at rates that are 75-80% of those of untreated thylakoids. The Mg2+-ATPase activity of trypsin-treated thylakoids is coupled to inward proton translocation and 10 mM sulfite stimulates both proton uptake and ATP hydrolysis. It is concluded that cleavage of the gamma subunit of the ATP synthase by trypsin prevents inhibition of ATPase activity by the epsilon subunit, but only partially overcomes inhibition by Mg2+ and ADP during assay.
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Affiliation(s)
- Richard E McCarty
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, 21218, USA.
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7
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Sugiyama K, Hisabori T. Conformational change of the chloroplast ATP synthase on the enzyme activation process detected by the trypsin sensitivity of the gamma subunit. Biochem Biophys Res Commun 2003; 301:311-6. [PMID: 12565861 DOI: 10.1016/s0006-291x(02)03022-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Delta mu H(+) is known to stimulate the enzyme activity of chloroplast ATP synthase in addition to its important role as energy supply for ATP synthesis. In the present study, we focused on the relationship between the proton translocation via the membrane sector of ATP synthase, F(o), and the conformational change of the central stalk subunit gamma. The conformational change of CF(1) mainly at the gamma subunit was induced by the proton flow via F(o) in the absence of substrates. The effects of inhibitors on CF(o) or CF(1) for this conformational change were also examined. The observed conformational change was partially suppressed by ADP binding. From these results, we propose the Delta mu H(+)-dependent conformational change of CF(1) on the enzyme activation process, which is affected by both ADP binding to the catalytic sites and proton flow via F(o) portion.
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Affiliation(s)
- Kenji Sugiyama
- Chemical Resources Laboratory, Tokyo Institute of Technology, Nagatsuta 4259, Midori-Ku, Yokohama 226-8503, Japan
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8
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Malyan A, Allison W. Properties of noncatalytic sites of thioredoxin-activated chloroplast coupling factor 1. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1554:153-8. [PMID: 12160988 DOI: 10.1016/s0005-2728(02)00239-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Nucleotide binding properties of two vacant noncatalytic sites of thioredoxin-activated chloroplast coupling factor 1 (CF(1)) were studied. Kinetics of nucleotide binding to noncatalytic sites is described by the first-order equation that allows for two nucleotide binding sites that differ in kinetic features. Dependence of the nucleotide binding rate on nucleotide concentration suggests that tight nucleotide binding is preceded by rapid reversible binding of nucleotides. ADP binding is cooperative. The preincubation of CF(1) with Mg(2+) produces only slight effect on the rate of ADP binding and decreases the ATP binding rate. The ATP and ADP dissociation from noncatalytic sites is described by the first-order equation for similar sites with dissociation rate constants k(-2)(ADP)=1.5 x 10(-1) min(-1) and k(-2)(ATP) congruent with 10(-3) min(-1), respectively. As follows from the study, the noncatalytic sites of CF(1) are not homogeneous. One of them retains the major part of endogenous ADP after CF(1) precipitation with ammonium sulfate. Its other two sites can bind both ADP and ATP but have different kinetic parameters and different affinity for nucleotides.
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Affiliation(s)
- Alexander Malyan
- Laboratory of Bioenergetics of Photosynthesis, Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Region 142290, Moscow, Russia.
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9
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Andralojc P, Harris D. Two distinct types of ɛ-binding site exist in chloroplast coupling factor (CF1). FEBS Lett 2001. [DOI: 10.1016/0014-5793(88)80471-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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10
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Richter ML, Hein R, Huchzermeyer B. Important subunit interactions in the chloroplast ATP synthase. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1458:326-42. [PMID: 10838048 DOI: 10.1016/s0005-2728(00)00084-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
General structural features of the chloroplast ATP synthase are summarized highlighting differences between the chloroplast enzyme and other ATP synthases. Much of the review is focused on the important interactions between the epsilon and gamma subunits of the chloroplast coupling factor 1 (CF(1)) which are involved in regulating the ATP hydrolytic activity of the enzyme and also in transferring energy from the membrane segment, chloroplast coupling factor 0 (CF(0)), to the catalytic sites on CF(1). A simple model is presented which summarizes properties of three known states of activation of the membrane-bound form of CF(1). The three states can be explained in terms of three different bound conformational states of the epsilon subunit. One of the three states, the fully active state, is only found in the membrane-bound form of CF(1). The lack of this state in the isolated form of CF(1), together with the confirmed presence of permanent asymmetry among the alpha, beta and gamma subunits of isolated CF(1), indicate that ATP hydrolysis by isolated CF(1) may involve only two of the three potential catalytic sites on the enzyme. Thus isolated CF(1) may be different from other F(1) enzymes in that it only operates on 'two cylinders' whereby the gamma subunit does not rotate through a full 360 degrees during the catalytic cycle. On the membrane in the presence of a light-induced proton gradient the enzyme assumes a conformation which may involve all three catalytic sites and a full 360 degrees rotation of gamma during catalysis.
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Affiliation(s)
- M L Richter
- Department of Molecular Biosciences, The University of Kansas, Lawrence 66045, USA
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11
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Schwarz O, Schürmann P, Strotmann H. Kinetics and thioredoxin specificity of thiol modulation of the chloroplast H+-ATPase. J Biol Chem 1997; 272:16924-7. [PMID: 9202002 DOI: 10.1074/jbc.272.27.16924] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The kinetics of thiol modulation of the chloroplast H+-ATPase (CF0CF1) in membrana were analyzed by employing thioredoxins that were kept reduced by 0.1 mM dithiothreitol. The kinetics of thiol modulation depend on the extent of the proton gradient. The process is an exponential function of the thioredoxin concentration and reaction time and can be described by an irreversible second order reaction. The results indicate that the formation of the complex between thioredoxin and CF0CF1 is slow compared with the subsequent reduction step. Furthermore we have compared the efficiencies of the Escherichia coli thioredoxin Trx and the two chloroplast thioredoxins Tr-m and Tr-f. The second order rate constants are 0.057 (Tr-f), 0.024 (Trx), and 0.010 s-1 microM-1 (Tr-m) suggesting that Tr-f rather than Tr-m is the physiological reductant for the chloroplast ATPase. The often employed artificial reductant dithiothreitol exhibits a second order rate constant in thiol modulation of 1.02.10(-6) s-1 microM-1.
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Affiliation(s)
- O Schwarz
- Institut für Biochemie der Pflanzen, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, D-40225 Düsseldorf, Federal Republic of Germany
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Howitt SM, Rodgers AJ, Hatch LP, Gibson F, Cox GB. The coupling of the relative movement of the a and c subunits of the F0 to the conformational changes in the F1-ATPase. J Bioenerg Biomembr 1996; 28:415-20. [PMID: 8951088 DOI: 10.1007/bf02113983] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
F0F1-ATPase structural information gained from X-ray crystallography and electron microscopy has activated interest in a rotational mechanism for the F0F1-ATPase. Because of the subunit stoichiometry and the involvement of both a- and c-subunits in the mechanism of proton movement, it is argued that relative movement must occur between the subunits. Various options for the arrangement and structure of the subunits involved are discussed and a mechanism proposed.
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Affiliation(s)
- S M Howitt
- Division of Biochemistry and Molecular Biology, John Curtin School of Medical Research, Australian National University, Canberra
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13
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Richter ML, Gao F. The chloroplast ATP synthase: structural changes during catalysis. J Bioenerg Biomembr 1996; 28:443-9. [PMID: 8951092 DOI: 10.1007/bf02113987] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
This article summarizes some of the evidence for the existence of light-driven structural changes in the epsilon and gamma subunits of the chloroplast ATP synthase. Formation of a transmembrane proton gradient results in: (1) a changed in the position of the epsilon subunit such that it becomes exposed to polyclonal antibodies and to reagents which selectively modify epsilon Lys109; (2) enhanced solvent accessibility of several sulfhydryl residues on the gamma subunit; and (3) release/exchange of tightly bound ADP from the enzyme. Theses and related experimental observations can, at least partially, be explained in terms of two different bound conformational states of the epsilon subunit. Evidence for structural changes in the enzyme which are driven by light or nucleotide binding is discussed with special reference to the popular rotational model for catalysis.
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Affiliation(s)
- M L Richter
- Department of Biochemistry, University of Kansas, Lawrence 66045, USA
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14
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Nakamoto RK, al-Shawi MK, Futai M. The ATP synthase gamma subunit. Suppressor mutagenesis reveals three helical regions involved in energy coupling. J Biol Chem 1995; 270:14042-6. [PMID: 7775464 DOI: 10.1074/jbc.270.23.14042] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
A role in coupling proton transport to catalysis of ATP synthesis has been demonstrated for the Escherichia coli F0F1 ATP synthase gamma subunit. Previously, functional interactions between the terminal regions that were important for coupling were shown by finding several mutations in the carboxyl-terminal region of the gamma subunit (involving residues at positions 242 and 269-280) that restored efficient coupling to the mutation, gamma Met-23-->Lys (Nakamoto, R. K., Maeda, M., and Futai, M. (1993) J. Biol. Chem. 268, 867-872). In this study, we used suppressor mutagenesis to establish that the terminal regions can be separated into three interacting segments. Second-site mutations that cause pseudo reversion of the primary mutations, gamma Gln-269-->Glu or gamma Thr-273-->Val, map to an amino-terminal segment with changes at residues 18, 34, and 35, and to a segment near the carboxyl terminus with changes at residues 236, 238, 242, and 246. Each second-site mutation suppressed the effects of both gamma Gln-269-->Glu and gamma Thr-273-->Val, and restored efficient coupling to enzyme complexes containing either of the primary mutations. Mapping of these residues in the recently reported x-ray crystallographic structure of the F1 complex (Abrahams, J. P., Leslie, A. G., Lutter, R., and Walker, J. E. (1994) Nature 370, 621-628), reveals that the second-site mutations do not directly interact with gamma Gln-269 and gamma Thr-273 and that the effect of suppression occurs at a distance. We propose that the three gamma subunit segments defined by suppressor mutagenesis, residues gamma 18-35, gamma 236-246, and gamma 269-280, constitute a domain that is critical for both catalytic function and energy coupling.
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Affiliation(s)
- R K Nakamoto
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville 22908, USA
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16
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Ren HM, Wei JM, Shen YK. Malate regulation of Mg(2+)-ATPase of chloroplast coupling factor 1. PHOTOSYNTHESIS RESEARCH 1995; 43:19-25. [PMID: 24306635 DOI: 10.1007/bf00029458] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/1994] [Accepted: 11/15/1994] [Indexed: 06/02/2023]
Abstract
The regulatory effects of malate on chloroplast Mg(2+)-ATPase were investigated and the mechanism was discussed. Malate stimulated methanol-activated membrane-bound and isolated CF1 Mg(2+)-ATPase activity. The γ subunit of CF1 may be involved in malate regulation of the enzyme function. Modification of γ subunit at one site of the peptide by NEM may affect malate stimulation of ATPase while at another site may have no effect. The effect of malate on the Mg(2+)-ATPase was also controlled by the Mg(2+)/ATP ratio in the reaction medium. The enhancing effect of malate on Mg(2+)-ATPase activity depended on the presence of high concentrations of Mg(2+) in the reaction mixture. Kinetic study showed that malate raised the Vmax of catalysis without affecting the Km for Mg(2+) ATP. The experiments imply that the stimulation of Mg(2+)-ATPase by malate is probably correlated with the Pi binding site on the enzyme. The regulation of ATPase activity by malate in chloroplasts may be relevant to its function in vivo.
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Affiliation(s)
- H M Ren
- Shanghai Institute of Plant Physiology, Chinese Academy of Sciences, 300 Fenglin Road, 200032, Shanghai, China
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17
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Fielder HR, Ponomarenko S, von Gehlen N, Strotmann H. Proton gradient-induced changes of the interaction between CF0 and CF1 as probed by cleavage with NaSCN. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1994. [DOI: 10.1016/0005-2728(94)90018-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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18
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Soteropoulos P, Ong A, McCarty R. Alkylation of cysteine 89 of the gamma subunit of chloroplast coupling factor 1 with N-ethylmaleimide alters nucleotide interactions. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)32092-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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19
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Iraburu MJ, Lopez-Zabalza MJ, Saenz M, Santiago E. Molecular aspects of activation mechanisms of CF₁. PHYTOCHEMISTRY 1994; 36:559-563. [PMID: 21657091 DOI: 10.1016/s0031-9422(00)89774-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The Ca²( +) -dependent ATPase activity of spinach chloroplast coupling factor 1 (CF₁) is activated by treatment with dithiothreitol (DDT). If excess of this reagent is eliminated by gel filtration, an Eadie-Hofstee biphasic plot is obtained. These results are consistent with the existence of two active forms of the enzyme governed by the redox state. We have observed that SDS-polyacrylamide gel electrophoresis pattern is affected by the pretreatment of the samples under those two different conditions. Spontaneous activation of the samples, due to a limited proteolytic process, has also been detected. In this case the electrophoretic pattern was also affected. The protease implied in this process could be a cystein protease co-isolated with CF₁. These observations suggest that limited proteolysis, as well as redox-induced changes, are involved in the physiological regulation of the enzyme.
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20
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Boyer PD. The binding change mechanism for ATP synthase--some probabilities and possibilities. BIOCHIMICA ET BIOPHYSICA ACTA 1993; 1140:215-50. [PMID: 8417777 DOI: 10.1016/0005-2728(93)90063-l] [Citation(s) in RCA: 716] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- P D Boyer
- Department of Chemistry and Biochemistry, University of California, Los Angeles 90024-1570
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21
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Nakamoto R, Maeda M, Futai M. The gamma subunit of the Escherichia coli ATP synthase. Mutations in the carboxyl-terminal region restore energy coupling to the amino-terminal mutant gamma Met-23–>Lys. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)54014-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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22
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Modifications of the gamma subunit of chloroplast coupling factor 1 alter interactions with the inhibitory epsilon subunit. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)50025-4] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Activation of the H+-ATP synthases of a thermophilic cyanobacterium and chloroplasts — a comparative study. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1991. [DOI: 10.1016/s0005-2728(05)80241-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Xiao J, McCarty RE. Binding of chloroplast coupling factor 1 deficient in the δ subunit to thylakoid membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1989. [DOI: 10.1016/s0005-2728(89)80231-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Miki J, Maeda M, Mukohata Y, Futai M. The gamma-subunit of ATP synthase from spinach chloroplasts. Primary structure deduced from the cloned cDNA sequence. FEBS Lett 1988; 232:221-6. [PMID: 2896606 DOI: 10.1016/0014-5793(88)80421-6] [Citation(s) in RCA: 110] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
cDNA clones encoding the gamma-subunit of chloroplast ATP synthase were isolated from a spinach library using synthetic oligonucleotide probes. The predicted amino acid sequence indicated that the mature chloroplast gamma-subunit consists of 323 amino acid residues and is highly homologous (55% identical residues) with the sequence of the cyanobacterial subunit. The positions of the four cysteine residues were identified. The carboxyl-terminal region of the chloroplast gamma-subunit is highly homologous with those of the gamma-subunits from six other sources (bacteria and mitochondria) sequenced thus far.
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Affiliation(s)
- J Miki
- Department of Organic Chemistry and Biochemistry, Osaka University, Japan
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Proteolytic enzymes stimulate both the ATP synthesis and hydrolysis functions of the chloroplast ATPase complex. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1988. [DOI: 10.1016/0005-2728(88)90067-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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NALIN CARLOM, NELSON NATHAN. Structure and Biogenesis of Chloroplast Coupling Factor CF0CF1-ATPase. ACTA ACUST UNITED AC 1987. [DOI: 10.1016/b978-0-12-152515-6.50013-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
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28
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Partial proteolysis as a probe of the conformation of the gamma subunit in activated soluble and membrane-bound chloroplast coupling factor 1. J Biol Chem 1985. [DOI: 10.1016/s0021-9258(17)39104-4] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Transient stimulation of light-triggered ATP hydrolysis by preillumination of chloroplasts in the presence of ATP. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1985. [DOI: 10.1016/0005-2728(85)90167-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Patrie WJ, McCarty RE. Specific binding of coupling factor 1 lacking the delta and epsilon subunits to thylakoids. J Biol Chem 1984. [DOI: 10.1016/s0021-9258(18)90630-7] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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31
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Characterization of the cysteinyl-containing peptides of the gamma subunit of coupling factor 1. J Biol Chem 1984. [DOI: 10.1016/s0021-9258(17)39869-1] [Citation(s) in RCA: 99] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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32
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Role of the gamma subunit of chloroplast coupling factor 1 in the light-dependent activation of photophosphorylation and ATPase activity by dithiothreitol. J Biol Chem 1984. [DOI: 10.1016/s0021-9258(17)39870-8] [Citation(s) in RCA: 163] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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33
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Nalin CM, Béliveau R, McCarty RE. Selective modification of coupling factor 1 in spinach chloroplast thylakoids by a fluorescent maleimide. J Biol Chem 1983. [DOI: 10.1016/s0021-9258(18)32871-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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34
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Cerione RA, McCarty RE, Hammes GG. Spatial relationships between specific sites on reconstituted chloroplast proton adenosinetriphosphatase and the phospholipid vesicle surface. Biochemistry 1983; 22:769-76. [PMID: 6220736 DOI: 10.1021/bi00273a010] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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35
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Moroney JV, Warncke K, McCarty RE. The distance between thiol groups in the gamma subunit of coupling factor 1 influences the proton permeability of thylakoid membranes. J Bioenerg Biomembr 1982; 14:347-59. [PMID: 6298195 DOI: 10.1007/bf00743063] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Spinach chloroplast thylakoids treated in the light with bifunctional maleimides were previously shown to be uncoupled. The increase in proton permeability by these reagents is caused by the cross-linking of an accessible group on the gamma subunit of coupling factor 1 (CF1) to a group that becomes exposed to reaction with maleimides only when the thylakoids are energized. In this study, several bifunctional maleimides, including o-, m-, and p-phenylenebismaleimides, 2,3- and 1,5-naphthalenebismaleimides, and azophenylbismaleimide, were tested for their ability to form cross-links and to uncouple photophosphorylation. These reagents form cross-links from about 6 to 19 A. Each reagent was found to form cross-links in the light and to inhibit photophosphorylation. However, the effectiveness of these compounds as uncouplers decreased as the distance between the cross-linked groups increased, indicating that the distance between two groups on the gamma subunit of CF1 can regulate proton flux through the membrane. Monofunctional maleimides cause a light-dependent energy transfer type of inhibition of photophosphorylation. Although this inhibition was correlated to the reaction of the maleimide with a group on the gamma subunit that is exposed only in energized thylakoids, the accessible group on this subunit was also modified by the reagent. However, we show here that the accessible group plays no role in the inhibition of photophosphorylation. This group may be blocked by incubating thylakoids in the dark with methyl methanethiolsulfonate. The light-dependent inhibition of photophosphorylation by N-ethylmaleimide was unaffected by this treatment or by the subsequent removal of the methanethiol moiety from the accessible group.
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Effect of ATPase activation and the delta subunit of coupling factor 1 on reconstitution of photophosphorylation. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(18)33972-3] [Citation(s) in RCA: 69] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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