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Perrin ME, Li B, Mbianda J, Bakail M, André C, Moal G, Legrand P, Ropars V, Douat C, Ochsenbein F, Guichard G. Unexpected binding modes of inhibitors to the histone chaperone ASF1 revealed by a foldamer scanning approach. Chem Commun (Camb) 2023. [PMID: 37347155 DOI: 10.1039/d3cc01891a] [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: 06/23/2023]
Abstract
In the search for foldamer inhibitors of the histone chaperone ASF1, we explored the possibility of substituting four α-residues (≈one helix turn) by 3-urea segments and scanned the sequence of a short α-helical peptide known to bind ASF1. By analysing the impact of the different foldamer replacements within the peptide chain, we uncovered new binding modes of the peptide-urea chimeras to ASF1.
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Affiliation(s)
- Marie E Perrin
- Joliot Institute, Commissariat à l'énergie Atomique (CEA), Direction de la Recherche Fondamentale (DRF), CEA Saclay, 91191 Gif-sur-Yvette, France.
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Bo Li
- Univ. Bordeaux, CNRS, Bordeaux INP, CBMN, UMR 5248, Institut Européen de Chimie et Biologie, F-33600 Pessac, France.
| | - Johanne Mbianda
- Univ. Bordeaux, CNRS, Bordeaux INP, CBMN, UMR 5248, Institut Européen de Chimie et Biologie, F-33600 Pessac, France.
| | - May Bakail
- Joliot Institute, Commissariat à l'énergie Atomique (CEA), Direction de la Recherche Fondamentale (DRF), CEA Saclay, 91191 Gif-sur-Yvette, France.
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Christophe André
- Univ. Bordeaux, CNRS, Bordeaux INP, CBMN, UMR 5248, Institut Européen de Chimie et Biologie, F-33600 Pessac, France.
| | - Gwenaëlle Moal
- Joliot Institute, Commissariat à l'énergie Atomique (CEA), Direction de la Recherche Fondamentale (DRF), CEA Saclay, 91191 Gif-sur-Yvette, France.
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Pierre Legrand
- Synchrotron SOLEIL, L'Orme des Merisiers, 91190 Gif-sur-Yvette, France
| | - Virginie Ropars
- Joliot Institute, Commissariat à l'énergie Atomique (CEA), Direction de la Recherche Fondamentale (DRF), CEA Saclay, 91191 Gif-sur-Yvette, France.
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Céline Douat
- Univ. Bordeaux, CNRS, Bordeaux INP, CBMN, UMR 5248, Institut Européen de Chimie et Biologie, F-33600 Pessac, France.
| | - Françoise Ochsenbein
- Joliot Institute, Commissariat à l'énergie Atomique (CEA), Direction de la Recherche Fondamentale (DRF), CEA Saclay, 91191 Gif-sur-Yvette, France.
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Gilles Guichard
- Univ. Bordeaux, CNRS, Bordeaux INP, CBMN, UMR 5248, Institut Européen de Chimie et Biologie, F-33600 Pessac, France.
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Mbianda J, Bakail M, André C, Moal G, Perrin ME, Pinna G, Guerois R, Becher F, Legrand P, Traoré S, Douat C, Guichard G, Ochsenbein F. Optimal anchoring of a foldamer inhibitor of ASF1 histone chaperone through backbone plasticity. Sci Adv 2021; 7:7/12/eabd9153. [PMID: 33741589 PMCID: PMC7978421 DOI: 10.1126/sciadv.abd9153] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 01/27/2021] [Indexed: 05/08/2023]
Abstract
Sequence-specific oligomers with predictable folding patterns, i.e., foldamers, provide new opportunities to mimic α-helical peptides and design inhibitors of protein-protein interactions. One major hurdle of this strategy is to retain the correct orientation of key side chains involved in protein surface recognition. Here, we show that the structural plasticity of a foldamer backbone may notably contribute to the required spatial adjustment for optimal interaction with the protein surface. By using oligoureas as α helix mimics, we designed a foldamer/peptide hybrid inhibitor of histone chaperone ASF1, a key regulator of chromatin dynamics. The crystal structure of its complex with ASF1 reveals a notable plasticity of the urea backbone, which adapts to the ASF1 surface to maintain the same binding interface. One additional benefit of generating ASF1 ligands with nonpeptide oligourea segments is the resistance to proteolysis in human plasma, which was highly improved compared to the cognate α-helical peptide.
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Affiliation(s)
- Johanne Mbianda
- Univ. Bordeaux, CNRS, Bordeaux INP, CBMN, UMR 5248, Institut Européen de Chimie et Biologie, 2 rue Robert Escarpit, F-33607 Pessac, France
| | - May Bakail
- Institute Joliot, Commissariat à l'énergie Atomique (CEA), Direction de la Recherche Fondamentale (DRF), CEA Saclay, F91191 Gif-sur-Yvette, France
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - Christophe André
- Univ. Bordeaux, CNRS, Bordeaux INP, CBMN, UMR 5248, Institut Européen de Chimie et Biologie, 2 rue Robert Escarpit, F-33607 Pessac, France
| | - Gwenaëlle Moal
- Institute Joliot, Commissariat à l'énergie Atomique (CEA), Direction de la Recherche Fondamentale (DRF), CEA Saclay, F91191 Gif-sur-Yvette, France
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - Marie E Perrin
- Institute Joliot, Commissariat à l'énergie Atomique (CEA), Direction de la Recherche Fondamentale (DRF), CEA Saclay, F91191 Gif-sur-Yvette, France
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - Guillaume Pinna
- Institute Joliot, Commissariat à l'énergie Atomique (CEA), Direction de la Recherche Fondamentale (DRF), CEA Saclay, F91191 Gif-sur-Yvette, France
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - Raphaël Guerois
- Institute Joliot, Commissariat à l'énergie Atomique (CEA), Direction de la Recherche Fondamentale (DRF), CEA Saclay, F91191 Gif-sur-Yvette, France
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - Francois Becher
- Institute Joliot, Commissariat à l'énergie Atomique (CEA), Direction de la Recherche Fondamentale (DRF), CEA Saclay, F91191 Gif-sur-Yvette, France
| | - Pierre Legrand
- Synchrotron SOLEIL, L'Orme des Merisiers, F91190 Gif-sur-Yvette, France
| | - Seydou Traoré
- Institute Joliot, Commissariat à l'énergie Atomique (CEA), Direction de la Recherche Fondamentale (DRF), CEA Saclay, F91191 Gif-sur-Yvette, France
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - Céline Douat
- Univ. Bordeaux, CNRS, Bordeaux INP, CBMN, UMR 5248, Institut Européen de Chimie et Biologie, 2 rue Robert Escarpit, F-33607 Pessac, France
| | - Gilles Guichard
- Univ. Bordeaux, CNRS, Bordeaux INP, CBMN, UMR 5248, Institut Européen de Chimie et Biologie, 2 rue Robert Escarpit, F-33607 Pessac, France.
| | - Françoise Ochsenbein
- Institute Joliot, Commissariat à l'énergie Atomique (CEA), Direction de la Recherche Fondamentale (DRF), CEA Saclay, F91191 Gif-sur-Yvette, France.
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
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Bakail M, Gaubert A, Andreani J, Moal G, Pinna G, Boyarchuk E, Gaillard MC, Courbeyrette R, Mann C, Thuret JY, Guichard B, Murciano B, Richet N, Poitou A, Frederic C, Le Du MH, Agez M, Roelants C, Gurard-Levin ZA, Almouzni G, Cherradi N, Guerois R, Ochsenbein F. Design on a Rational Basis of High-Affinity Peptides Inhibiting the Histone Chaperone ASF1. Cell Chem Biol 2019; 26:1573-1585.e10. [PMID: 31543461 DOI: 10.1016/j.chembiol.2019.09.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [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: 06/13/2018] [Revised: 06/12/2019] [Accepted: 09/03/2019] [Indexed: 12/16/2022]
Abstract
Anti-silencing function 1 (ASF1) is a conserved H3-H4 histone chaperone involved in histone dynamics during replication, transcription, and DNA repair. Overexpressed in proliferating tissues including many tumors, ASF1 has emerged as a promising therapeutic target. Here, we combine structural, computational, and biochemical approaches to design peptides that inhibit the ASF1-histone interaction. Starting from the structure of the human ASF1-histone complex, we developed a rational design strategy combining epitope tethering and optimization of interface contacts to identify a potent peptide inhibitor with a dissociation constant of 3 nM. When introduced into cultured cells, the inhibitors impair cell proliferation, perturb cell-cycle progression, and reduce cell migration and invasion in a manner commensurate with their affinity for ASF1. Finally, we find that direct injection of the most potent ASF1 peptide inhibitor in mouse allografts reduces tumor growth. Our results open new avenues to use ASF1 inhibitors as promising leads for cancer therapy.
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Affiliation(s)
- May Bakail
- Institute Joliot, Commissariat à l'énergie Atomique (CEA), Direction de la Recherche Fondamentale (DRF), 91191 Gif-sur-Yvette, France; Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette Cedex, France
| | - Albane Gaubert
- Institute Joliot, Commissariat à l'énergie Atomique (CEA), Direction de la Recherche Fondamentale (DRF), 91191 Gif-sur-Yvette, France
| | - Jessica Andreani
- Institute Joliot, Commissariat à l'énergie Atomique (CEA), Direction de la Recherche Fondamentale (DRF), 91191 Gif-sur-Yvette, France; Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette Cedex, France
| | - Gwenaëlle Moal
- Institute Joliot, Commissariat à l'énergie Atomique (CEA), Direction de la Recherche Fondamentale (DRF), 91191 Gif-sur-Yvette, France; Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette Cedex, France
| | - Guillaume Pinna
- Institute Joliot, Commissariat à l'énergie Atomique (CEA), Direction de la Recherche Fondamentale (DRF), 91191 Gif-sur-Yvette, France; Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette Cedex, France
| | - Ekaterina Boyarchuk
- Institut Curie, Paris Sciences et Lettres (PSL) Research University, CNRS, UMR3664, Equipe Labellisée Ligue Contre le Cancer, 75005 Paris, France; Sorbonne Universités, UPMC Univ Paris 06, CNRS, UMR3664, 75005 Paris, France
| | - Marie-Cécile Gaillard
- Institute Joliot, Commissariat à l'énergie Atomique (CEA), Direction de la Recherche Fondamentale (DRF), 91191 Gif-sur-Yvette, France; Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette Cedex, France
| | - Regis Courbeyrette
- Institute Joliot, Commissariat à l'énergie Atomique (CEA), Direction de la Recherche Fondamentale (DRF), 91191 Gif-sur-Yvette, France; Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette Cedex, France
| | - Carl Mann
- Institute Joliot, Commissariat à l'énergie Atomique (CEA), Direction de la Recherche Fondamentale (DRF), 91191 Gif-sur-Yvette, France; Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette Cedex, France
| | - Jean-Yves Thuret
- Institute Joliot, Commissariat à l'énergie Atomique (CEA), Direction de la Recherche Fondamentale (DRF), 91191 Gif-sur-Yvette, France; Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette Cedex, France
| | - Bérengère Guichard
- Institute Joliot, Commissariat à l'énergie Atomique (CEA), Direction de la Recherche Fondamentale (DRF), 91191 Gif-sur-Yvette, France
| | - Brice Murciano
- Institute Joliot, Commissariat à l'énergie Atomique (CEA), Direction de la Recherche Fondamentale (DRF), 91191 Gif-sur-Yvette, France
| | - Nicolas Richet
- Institute Joliot, Commissariat à l'énergie Atomique (CEA), Direction de la Recherche Fondamentale (DRF), 91191 Gif-sur-Yvette, France
| | - Adeline Poitou
- Institute Joliot, Commissariat à l'énergie Atomique (CEA), Direction de la Recherche Fondamentale (DRF), 91191 Gif-sur-Yvette, France
| | - Claire Frederic
- Institute Joliot, Commissariat à l'énergie Atomique (CEA), Direction de la Recherche Fondamentale (DRF), 91191 Gif-sur-Yvette, France
| | - Marie-Hélène Le Du
- Institute Joliot, Commissariat à l'énergie Atomique (CEA), Direction de la Recherche Fondamentale (DRF), 91191 Gif-sur-Yvette, France; Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette Cedex, France
| | - Morgane Agez
- Institute Joliot, Commissariat à l'énergie Atomique (CEA), Direction de la Recherche Fondamentale (DRF), 91191 Gif-sur-Yvette, France
| | - Caroline Roelants
- Institut National de la Santé et de la Recherche Médicale, Unité 1036, 38000 Grenoble, France; Commissariat à l'Energie Atomique, Institut de Recherche Interdisciplinaire de Grenoble, Biologie du Cancer et de l'Infection, 38000 Grenoble, France; Université Grenoble Alpes, Unité Mixte de Recherche-S1036, 38000 Grenoble, France
| | - Zachary A Gurard-Levin
- Institut Curie, Paris Sciences et Lettres (PSL) Research University, CNRS, UMR3664, Equipe Labellisée Ligue Contre le Cancer, 75005 Paris, France; Sorbonne Universités, UPMC Univ Paris 06, CNRS, UMR3664, 75005 Paris, France
| | - Geneviève Almouzni
- Institut Curie, Paris Sciences et Lettres (PSL) Research University, CNRS, UMR3664, Equipe Labellisée Ligue Contre le Cancer, 75005 Paris, France; Sorbonne Universités, UPMC Univ Paris 06, CNRS, UMR3664, 75005 Paris, France
| | - Nadia Cherradi
- Institut National de la Santé et de la Recherche Médicale, Unité 1036, 38000 Grenoble, France; Commissariat à l'Energie Atomique, Institut de Recherche Interdisciplinaire de Grenoble, Biologie du Cancer et de l'Infection, 38000 Grenoble, France; Université Grenoble Alpes, Unité Mixte de Recherche-S1036, 38000 Grenoble, France
| | - Raphael Guerois
- Institute Joliot, Commissariat à l'énergie Atomique (CEA), Direction de la Recherche Fondamentale (DRF), 91191 Gif-sur-Yvette, France; Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette Cedex, France.
| | - Françoise Ochsenbein
- Institute Joliot, Commissariat à l'énergie Atomique (CEA), Direction de la Recherche Fondamentale (DRF), 91191 Gif-sur-Yvette, France; Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette Cedex, France.
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Moal G, Lagoutte B. Photo-induced electron transfer from photosystem I to NADP(+): characterization and tentative simulation of the in vivo environment. Biochimica et Biophysica Acta (BBA) - Bioenergetics 2012; 1817:1635-45. [PMID: 22683536 DOI: 10.1016/j.bbabio.2012.05.015] [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] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Revised: 05/28/2012] [Accepted: 05/30/2012] [Indexed: 12/01/2022]
Abstract
The photoproduction of NADPH in photosynthetic organisms requires the successive or concomitant interaction of at least three proteins: photosystem I (PSI), ferredoxin (Fd) and ferredoxin:NADP(+) oxidoreductase (FNR). These proteins and their surrounding medium have been carefully analysed in the cyanobacterium Synechocystis sp. PCC 6803. A high value of 550mg/ml was determined for the overall solute content of the cell soluble compartment. PSI and Fd are present at similar concentrations, around 500μM, whereas the FNR associated to phycobilisome is about 4 fold less concentrated. Membrane densities of FNR and trimeric PSI have been estimated to 2000 and 2550 per μm(2), respectively. An artificial confinement of Fd to PSI was designed using fused constructs between Fd and PsaE, a peripheral and stroma located PSI subunit. The best covalent system in terms of photocatalysed NADPH synthesis can be equivalent to the free system in a dilute medium. In a macrosolute crowded medium (375mg/ml), this optimized PSI/Fd covalent complex exhibited a huge superiority compared to the free system. This is a likely consequence of restrained diffusion constraints due to the vicinity of two out of the three protein partners. In vivo, Fd is the free partner, but the constant proximity between PSI and the phycobilisome associated FNR creates a similar situation, with two closely associated partners. This organization seems well adapted for an efficient in vivo production of the stable and fast diffusing NADPH.
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Affiliation(s)
- Gwenaëlle Moal
- Service de Bioenergetique, Biologie Structurale et Mecanismes, Gif sur Yvette, France
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Béraud G, Moal G, Elsendoorn A, Tattevin P, Godet C, Alfandari S, Couet W, Roblot P, Roblot F. A survey on the use of gentamicin in infective endocarditis. Eur J Clin Microbiol Infect Dis 2011; 31:1413-8. [DOI: 10.1007/s10096-011-1458-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Accepted: 10/11/2011] [Indexed: 10/15/2022]
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Elkaim JP, Moal G, Gilard M, Jobic Y, Etienne Y, Mansourati J, Blanc JJ, Boschat J. [Coronary prosthesis implantation. Immediate and mid-term results]. Arch Mal Coeur Vaiss 2001; 94:44-50. [PMID: 11233480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
The aim of this study was to evaluate the clinical events occurring after coronary stenting in a series of 318 consecutive patients treated in 1997. Hospital follow-up was by gathering all the data in the hospital record and medium-term follow-up was performed by questionnaire filled with the help of the patient, the attending physician and the referring cardiologist. The primary clinical success rate was 95.6% and the clinical follow-up rate was 98.7%. The follow-up period was at least 16 months (mean 22 +/- 6 months). The restenosis rate was 15% in the remaining population (318-7 deaths and 4 lost to follow-up) and 47% in the population undergoing control coronary angiography. No major clinical cardiac events (death, myocardial infarction or revascularisation) were observed in 80.5% at 1 year and 79% at 22 months. Twenty per cent of the remaining population had no non-invasive paraclinical investigations for myocardial ischaemia after coronary stenting. These results are comparable to those of the literature, indicating excellent feasibility of this technique and the fact that, programmed or not, coronary stenting is a safe procedure confirming its value in what has become everyday practice. Nevertheless, this experience did highlight certain lapses in medical follow-up and patient information.
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Affiliation(s)
- J P Elkaim
- Département de cardiologie, CHU de la Cavale blanche, 29609 Brest
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Guillouard I, Lagoutte B, Moal G, Bottin H. Importance of the region including aspartates 57 and 60 of ferredoxin on the electron transfer complex with photosystem I in the cyanobacterium Synechocystis sp. PCC 6803. Biochem Biophys Res Commun 2000; 271:647-53. [PMID: 10814516 DOI: 10.1006/bbrc.2000.2687] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ferredoxin reduction by photosystem I has been studied by flash-absorption spectroscopy. Aspartate residues 20, 57, and 60 of ferredoxin were changed to alanine, cysteine, arginine, or lysine. On the one hand, electron transfer from photosystem I to all mutated ferredoxins still occurs on a microsecond time scale, with half-times of ferredoxin reduction mostly conserved compared to wild-type ferredoxin. On the other hand, the total amplitude of the fast first-order reduction varies largely when residues 57 or 60 are modified, in apparent relation to the charge modification (neutralized or inverted). Substituting these two residues for lysine or arginine induce strong effects on ferredoxin binding (up to sixfold increase in K(D)), whereas the same substitution on aspartate 20, a spatially related residue, results in moderate effects (maximum twofold increase in K(D)). In addition, double mutations to arginine or lysine were performed on both aspartates 57 and 60. The mutated proteins have a 15- to 20-fold increased K(D) and show strong modifications in the amplitudes of the fast reduction kinetics. These results indicate that the acidic area of ferredoxin including aspartates 57 and 60, located opposite to the C-terminus, is crucial for high affinity interactions with photosystem I.
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Affiliation(s)
- I Guillouard
- CEA, Département de Biologie Cellulaire et Moléculaire, Section de Bioénergétique, CNRS URA 2096, CE de Saclay, Gif sur Yvette Cedex, 91191, France
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Santolini J, Haraux F, Sigalat C, Moal G, André F. Kinetic analysis of tentoxin binding to chloroplast F1-ATPase. A model for the overactivation process. J Biol Chem 1999; 274:849-58. [PMID: 9873024 DOI: 10.1074/jbc.274.2.849] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The mechanism of action of tentoxin on the soluble part (chloroplast F1 H+-ATPase; CF1) of chloroplast ATP synthase was analyzed in the light of new kinetic and equilibrium experiments. Investigations were done regarding the functional state of the enzyme (activation, bound nucleotide, catalytic turnover). Dialysis and binding data, obtained with 14C-tentoxin, fully confirmed the existence of two tentoxin binding sites of distinct dissociation constants consistent with the observed Kinhibition and Koveractivation. This strongly supports a two-site model of tentoxin action on CF1. Kinetic and thermodynamic parameters of tentoxin binding to the first site (Ki = 10 nM; kon = 4.7 x 10(4) s-1.M-1) were determined from time-resolved activity assays. Tentoxin binding to the high affinity site was found independent on the catalytic state of the enzyme. The analysis of the kinetics of tentoxin binding on the low affinity site of the enzyme showed strong evidence for an interaction between this site and the nucleotide binding sites and revealed a complex relationship between the catalytic state and the reactivation process. New catalytic states of CF1 devoid of epsilon-subunit were detected: a transient overstimulated state, and a dead end complex unable to bind a second tentoxin molecule. Our experiments led to a kinetic model for the reactivation phenomenon for which rate constants were determined. The implications of this model are discussed in relation to the previous mechanistic hypotheses on the effect of tentoxin.
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Affiliation(s)
- J Santolini
- Section de Bioénergétique, Département de Biologie Cellulaire et Moléculaire, Commissariat à l'Energie Atomique-Saclay, F-91191 Gif-sur-Yvette Cedex, France.
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