1
|
Subran B, Mauhin W, London J, Montagner C, Mellot C, Lidove O. Responsabilisation des externes quand à l’apprentissage de la sémiologie en stage hospitalier. Rev Med Interne 2021. [DOI: 10.1016/j.revmed.2021.10.228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
2
|
Mauhin W, Bouzidi H, Colson A, Lejour G, Miao Y, Montagner C, London J, Subran B, Amathieu R, Lazard T, Lidove O. [Fatal nutrient deficiencies after gastric bypass]. Rev Med Interne 2021; 42:729-733. [PMID: 34144843 DOI: 10.1016/j.revmed.2021.05.007] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 04/01/2021] [Accepted: 05/09/2021] [Indexed: 11/16/2022]
Abstract
INTRODUCTION Bariatric surgery is a very effective treatment for obesity. After gastric bypass, micronutrient deficiencies frequently occur which can have dramatic consequences. CASE REPORT We report the case of a 55-year-old woman who was admitted for psychomotor retardation, bilateral leg pitting edema and psoriasis-like rash that had been ongoing for 3 months. Pancytopenia, encephalopathy and heart failure rapidly occurred leading to multiorgan dysfunction syndrome and death. We retrospectively identified severe selenium deficiency with possible secondary cardiomyopathy, niacin deficiency resulting in pellagrous encephalopathy with skin lesions and gelatinous transformation of bone marrow. CONCLUSION Micronutrient deficiency should systematically be assessed when new symptoms occur in a patient with a history of bariatric surgery. Selenium deficiency should be considered in the presence of any heart failure in this context.
Collapse
Affiliation(s)
- W Mauhin
- Service de médecine interne, groupe hospitalier Diaconesses Croix-Saint-Simon, site Avron, 75020 Paris, France.
| | - H Bouzidi
- Service de réanimation, groupe hospitalier Diaconesses Croix-Saint-Simon, site Avron, 75020 Paris, France
| | - A Colson
- Service transversal de nutrition et diététique, Paris, France
| | - G Lejour
- Service de réanimation, groupe hospitalier Diaconesses Croix-Saint-Simon, site Avron, 75020 Paris, France
| | - Y Miao
- Service de médecine interne, groupe hospitalier Diaconesses Croix-Saint-Simon, site Avron, 75020 Paris, France
| | - C Montagner
- Service de médecine interne, groupe hospitalier Diaconesses Croix-Saint-Simon, site Avron, 75020 Paris, France
| | - J London
- Service de médecine interne, groupe hospitalier Diaconesses Croix-Saint-Simon, site Avron, 75020 Paris, France
| | - B Subran
- Service de médecine interne, groupe hospitalier Diaconesses Croix-Saint-Simon, site Avron, 75020 Paris, France
| | - R Amathieu
- Service de réanimation, groupe hospitalier Diaconesses Croix-Saint-Simon, site Avron, 75020 Paris, France
| | - T Lazard
- Service de réanimation, groupe hospitalier Diaconesses Croix-Saint-Simon, site Avron, 75020 Paris, France
| | - O Lidove
- Service de médecine interne, groupe hospitalier Diaconesses Croix-Saint-Simon, site Avron, 75020 Paris, France
| |
Collapse
|
3
|
Fredeau L, Karaa S, London J, Matignon MB, Blah N, Montagner C, Lidove O, Mauhin W. Image Gallery: Palmar vascular lesions, a tool for diagnosis and prognosis in Fabry disease. Br J Dermatol 2019; 182:e183. [PMID: 31875942 DOI: 10.1111/bjd.18786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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)
- L Fredeau
- Internal Medicine, Groupe Hospitalier Diaconesses Croix Saint-Simon Site Avron, Paris, France
| | - S Karaa
- Internal Medicine, Groupe Hospitalier Diaconesses Croix Saint-Simon Site Avron, Paris, France
| | - J London
- Internal Medicine, Groupe Hospitalier Diaconesses Croix Saint-Simon Site Avron, Paris, France.,Centre de Référence Maladies Lysosomales, Hôpital de la Croix Saint-Simon, Paris, France
| | - M B Matignon
- Nephrology and Renal Transplantation Department, Institut Francilien de Recherche en Néphrologie et Transplantation, Henri-Mondor/Albert-Chenevier University Hospital, APHP, Créteil, France.,University of Paris-Est-Créteil, Département Hospitalo-Universitaire Virus-Immunité-Cancer, Institut Mondor de Recherche Biomédicale, Team 21, INSERM U955, Créteil, France
| | - N Blah
- Internal Medicine, Groupe Hospitalier Diaconesses Croix Saint-Simon Site Avron, Paris, France
| | - C Montagner
- Internal Medicine, Groupe Hospitalier Diaconesses Croix Saint-Simon Site Avron, Paris, France.,Centre de Référence Maladies Lysosomales, Hôpital de la Croix Saint-Simon, Paris, France
| | - O Lidove
- Internal Medicine, Groupe Hospitalier Diaconesses Croix Saint-Simon Site Avron, Paris, France.,Centre de Référence Maladies Lysosomales, Hôpital de la Croix Saint-Simon, Paris, France
| | - W Mauhin
- Internal Medicine, Groupe Hospitalier Diaconesses Croix Saint-Simon Site Avron, Paris, France.,Centre de Référence Maladies Lysosomales, Hôpital de la Croix Saint-Simon, Paris, France
| |
Collapse
|
4
|
Montagner C, Bricou A, Selle F, Kafé H, Mauhin W, Fredeau L, Duval-Chopard L, Slama J, Durand P, Beal C, London J, Lidove O. [Glassy cell carcinoma of the uterine cervix: An aggressive type of cancer]. Rev Med Interne 2019; 40:754-757. [PMID: 31431320 DOI: 10.1016/j.revmed.2019.07.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 06/19/2019] [Accepted: 07/17/2019] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Cervical cancer is the twelfth most frequent cancer in women in France. Glassy cell carcinoma is a rare histological entity, rapidly aggressive, associated with a poor prognosis. CASE REPORT A 30-year-old woman was admitted in an internal medicine department for polyarthralgia with high grade fever, evolving for 3 weeks. There was an inflammatory syndrome. The 18-FDG-PET-scan showed inflammatory lymph nodes as well as disseminated osteolytic lesions, and a primitive pelvic tumor. A 3cm tumor of the cervix was found during the gynaecologic examination. Histological analysis elicited a high-index mitotic carcinoma, glassy cell carcinoma type. Despite chemotherapy, the outcome was poor, with early death occurring after three months of follow-up. CONCLUSION The glassy cell carcinoma of the cervix should be considered as an aetiology of bone metastases in young female patients.
Collapse
Affiliation(s)
- C Montagner
- Service de médecine interne, Groupe Hospitalier Diaconesses Croix Saint Simon, rue d'Avron, 75020 Paris, France.
| | - A Bricou
- Service de chirurgie gynécologique et mammaire, Groupe Hospitalier Diaconesses Croix Saint Simon, rue d'Avron, 75020 Paris, France
| | - F Selle
- Service d'oncologie, Groupe Hospitalier Diaconesses Croix Saint Simon, rue d'Avron 75020 Paris, France
| | - H Kafé
- Centre de pathologie, 19, rue de Passy, 75016, France
| | - W Mauhin
- Service de médecine interne, Groupe Hospitalier Diaconesses Croix Saint Simon, rue d'Avron, 75020 Paris, France
| | - L Fredeau
- Service de médecine interne, Groupe Hospitalier Diaconesses Croix Saint Simon, rue d'Avron, 75020 Paris, France
| | - L Duval-Chopard
- Service de médecine interne, Groupe Hospitalier Diaconesses Croix Saint Simon, rue d'Avron, 75020 Paris, France
| | - J Slama
- Paris Service de médecine nucléaire, Hôpital Beaujon, 100, boulevard du Général Leclerc, 92110 Clichy, France
| | - P Durand
- Service de radiologie, Groupe Hospitalier Diaconesses Croix Saint Simon, rue d'Avron, 75020 Paris, France
| | - C Beal
- Service de rhumatologie, Groupe Hospitalier Diaconesses Croix Saint Simon, rue d'Avron, 75020 Paris, France
| | - J London
- Service de médecine interne, Groupe Hospitalier Diaconesses Croix Saint Simon, rue d'Avron, 75020 Paris, France
| | - O Lidove
- Service de médecine interne, Groupe Hospitalier Diaconesses Croix Saint Simon, rue d'Avron, 75020 Paris, France
| |
Collapse
|
5
|
Dahmane I, Montagner C, Matagne A, Dumbre S, Herdewijn P, Terrak M. Peptidoglycan glycosyltransferase-ligand binding assay based on tryptophan fluorescence quenching. Biochimie 2018; 152:1-5. [PMID: 29909047 DOI: 10.1016/j.biochi.2018.06.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 06/13/2018] [Indexed: 11/28/2022]
Abstract
Peptidoglycan glycosyltransferases (GTase) of family 51 are essential enzymes for the synthesis of the glycan chains of the bacterial cell wall. They are considered potential antibacterial target, but discovery of inhibitors was hampered so far by the lack of efficient and affordable screening assay. Here we used Staphylococcus aureus MtgA to introduce a single tryptophan reporter residue in selected positions flanking the substrates binding cavity of the protein. We selected a mutant (Y181W) that shows strong fluorescence quenching in the presence of moenomycin A and two lipid II analogs inhibitors. The assay provides a simple method to study GTase-ligand interactions and can be used as primary high throughput screening of GTase inhibitors without the need for lipid II substrate or reporter ligands.
Collapse
Affiliation(s)
- Ismahene Dahmane
- Centre d'Ingénierie des Protéines-InBioS, University of Liège, B6a, Quartier Agora, Allée du six Août 11, 4000, Liège 1, Belgium
| | - Caroline Montagner
- Centre d'Ingénierie des Protéines-InBioS, University of Liège, B6a, Quartier Agora, Allée du six Août 11, 4000, Liège 1, Belgium
| | - André Matagne
- Centre d'Ingénierie des Protéines-InBioS, University of Liège, B6a, Quartier Agora, Allée du six Août 11, 4000, Liège 1, Belgium
| | - Shrinivas Dumbre
- Laboratory of Medicinal Chemistry, Rega Institute for Medical Research, University of Leuven, Belgium
| | - Piet Herdewijn
- Laboratory of Medicinal Chemistry, Rega Institute for Medical Research, University of Leuven, Belgium
| | - Mohammed Terrak
- Centre d'Ingénierie des Protéines-InBioS, University of Liège, B6a, Quartier Agora, Allée du six Août 11, 4000, Liège 1, Belgium.
| |
Collapse
|
6
|
Montagner C, Nigen M, Jacquin O, Willet N, Dumoulin M, Karsisiotis AI, Roberts GCK, Damblon C, Redfield C, Matagne A. The Role of Active Site Flexible Loops in Catalysis and of Zinc in Conformational Stability of Bacillus cereus 569/H/9 β-Lactamase. J Biol Chem 2016; 291:16124-37. [PMID: 27235401 DOI: 10.1074/jbc.m116.719005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [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: 03/03/2016] [Indexed: 11/06/2022] Open
Abstract
Metallo-β-lactamases catalyze the hydrolysis of most β-lactam antibiotics and hence represent a major clinical concern. The development of inhibitors for these enzymes is complicated by the diversity and flexibility of their substrate-binding sites, motivating research into their structure and function. In this study, we examined the conformational properties of the Bacillus cereus β-lactamase II in the presence of chemical denaturants using a variety of biochemical and biophysical techniques. The apoenzyme was found to unfold cooperatively, with a Gibbs free energy of stabilization (ΔG(0)) of 32 ± 2 kJ·mol(-1) For holoBcII, a first non-cooperative transition leads to multiple interconverting native-like states, in which both zinc atoms remain bound in an apparently unaltered active site, and the protein displays a well organized compact hydrophobic core with structural changes confined to the enzyme surface, but with no catalytic activity. Two-dimensional NMR data revealed that the loss of activity occurs concomitantly with perturbations in two loops that border the enzyme active site. A second cooperative transition, corresponding to global unfolding, is observed at higher denaturant concentrations, with ΔG(0) value of 65 ± 1.4 kJ·mol(-1) These combined data highlight the importance of the two zinc ions in maintaining structure as well as a relatively well defined conformation for both active site loops to maintain enzymatic activity.
Collapse
Affiliation(s)
- Caroline Montagner
- From the Laboratoire d'Enzymologie et Repliement des Protéines, Centre d'Ingénierie des Protéines, and
| | - Michaël Nigen
- From the Laboratoire d'Enzymologie et Repliement des Protéines, Centre d'Ingénierie des Protéines, and
| | - Olivier Jacquin
- From the Laboratoire d'Enzymologie et Repliement des Protéines, Centre d'Ingénierie des Protéines, and
| | - Nicolas Willet
- From the Laboratoire d'Enzymologie et Repliement des Protéines, Centre d'Ingénierie des Protéines, and
| | - Mireille Dumoulin
- From the Laboratoire d'Enzymologie et Repliement des Protéines, Centre d'Ingénierie des Protéines, and
| | - Andreas Ioannis Karsisiotis
- the School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, Essex CO4 3SQ, United Kingdom
| | - Gordon C K Roberts
- the Henry Wellcome Laboratories of Structural Biology, Department of Biochemistry, University of Leicester, Leicester LE1 9HN, United Kingdom, and
| | - Christian Damblon
- Département de Chimie, Université de Liège, Institut de Chimie B6, 4000 Liège (Sart Tilman), Belgium
| | - Christina Redfield
- the Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | - André Matagne
- From the Laboratoire d'Enzymologie et Repliement des Protéines, Centre d'Ingénierie des Protéines, and
| |
Collapse
|
7
|
Galloux M, Araye-Guet A, Vitrac H, Montagner C, Raffestin S, Popoff M, Chenal A, Forge V, Gillet D. Function of the translocation domain belt. Toxicon 2013. [DOI: 10.1016/j.toxicon.2012.07.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
8
|
Man P, Montagner C, Vitrac H, Kavan D, Pichard S, Gillet D, Forest E, Forge V. Accessibility Changes within Diphtheria Toxin T Domain upon Membrane Penetration Probed by Hydrogen Exchange and Mass Spectrometry. J Mol Biol 2011; 414:123-34. [DOI: 10.1016/j.jmb.2011.09.042] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Accepted: 09/26/2011] [Indexed: 01/25/2023]
|
9
|
Man P, Montagner C, Vitrac H, Kavan D, Pichard S, Gillet D, Forest E, Forge V. Accessibility changes within diphtheria toxin T domain when in the functional molten globule state, as determined using hydrogen/deuterium exchange measurements. FEBS J 2009; 277:653-62. [PMID: 20050921 DOI: 10.1111/j.1742-4658.2009.07511.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [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 translocation domain (T domain) of diphtheria toxin adopts a partially folded state, the so-called molten globule state, to become functional at acidic pH. We compared, using hydrogen/deuterium exchange experiments associated with MS, the structures of the T domain in its soluble folded state at neutral pH and in its functional molten globule state at acidic pH. In the native state, the alpha-helices TH5 and TH8 are identified as the core of the domain. Based on the high-resolution structure of the T domain, we propose that TH8 is highly protected because it is buried within the native structure. According to the same structure, TH5 is partly accessible at the surface of the T domain. We propose that its high protection is caused by the formation of dimers. Within the molten globule state, high protection is still observed within the helical hairpin TH8-TH9, which is responsible for the insertion of the T domain into the membrane. In the absence of the lipid bilayer, this hydrophobic part of the domain self-assembles, leading to the formation of oligomers. Overall, hydrogen/deuterium-exchange measurements allow the analysis of interaction contacts within small oligomers made of partially folded proteins. Such information, together with crystal structure data, are particularly valuable for using to analyze the self-assembly of proteins.
Collapse
Affiliation(s)
- Petr Man
- Laboratoire de Spectrométrie de Masse des Protéines, Institut de Biologie Structurale (CEA, CNRS, UJF, UMR 5075), Grenoble, France
| | | | | | | | | | | | | | | |
Collapse
|
10
|
Galloux M, Vitrac H, Montagner C, Raffestin S, Popoff MR, Chenal A, Forge V, Gillet D. Membrane Interaction of botulinum neurotoxin A translocation (T) domain. The belt region is a regulatory loop for membrane interaction. J Biol Chem 2008; 283:27668-27676. [PMID: 18693250 DOI: 10.1074/jbc.m802557200] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [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
The translocation of the catalytic domain through the membrane of the endosome to the cell cytoplasm is a key step of intoxication by botulinum neurotoxin (BoNT). This step is mediated by the translocation (T) domain upon endosome acidification, although the mechanism of interaction of the T domain with the membrane is still poorly understood. Using physicochemical approaches and spectroscopic methods, we studied the interaction of the BoNT/A T domain with the membrane as a function of pH. We found that the interaction with membranes does not involve major secondary or tertiary structural changes, as reported for other toxins like diphtheria toxin. The T domain becomes insoluble around its pI value and then penetrates into the membrane. At that stage, the T domain becomes able to permeabilize lipid vesicles. This occurs for pH values lower than 5.5, in agreement with the pH encountered by the toxin within endosomes. Electrostatic interactions are also important for the process. The role of the so-called belt region was investigated with four variant proteins presenting different lengths of the N-extremity of the T domain. We observed that this part of the T domain, which contains numerous negatively charged residues, limits the protein-membrane interaction. Indeed, interaction with the membrane of the protein deleted of this extremity takes place for higher pH values than for the entire T domain. Overall, the data suggest that acidification eliminates repulsive electrostatic interactions between the T domain and the membrane, allowing its penetration into the membrane without triggering detectable structural changes.
Collapse
Affiliation(s)
- Marie Galloux
- Commissariat à l'Energie Atomique (CEA), Institut de Biologie et Technologies de Saclay (iBiTecS), Service d'Ingénierie Moléculaire des Protéines (SIMOPRO), F-91191 Gif sur Yvette, France
| | - Heidi Vitrac
- Institut de Recherche en Technologies et Sciences pour le Vivant (IRTSV), Laboratoire de Chimie Biologie des Métaux (LCBM), UMR CEA-CNRS-UJF 5249, F-38054 Grenoble, France
| | - Caroline Montagner
- Institut de Recherche en Technologies et Sciences pour le Vivant (IRTSV), Laboratoire de Chimie Biologie des Métaux (LCBM), UMR CEA-CNRS-UJF 5249, F-38054 Grenoble, France
| | - Stéphanie Raffestin
- Commissariat à l'Energie Atomique (CEA), Institut de Biologie et Technologies de Saclay (iBiTecS), Service d'Ingénierie Moléculaire des Protéines (SIMOPRO), F-91191 Gif sur Yvette, France
| | - Michel R Popoff
- Institut Pasteur, Unité des Bactéries Anaérobies et Toxines, 75724 Paris cedex 15, France
| | - Alexandre Chenal
- Unité de Biochimie des Interactions Moléculaires, URA CNRS 2185, Département de Biologie Structurale et Chimie, 25-28 rue du Dr Roux, 75724 Paris cedex 15, France
| | - Vincent Forge
- Institut de Recherche en Technologies et Sciences pour le Vivant (IRTSV), Laboratoire de Chimie Biologie des Métaux (LCBM), UMR CEA-CNRS-UJF 5249, F-38054 Grenoble, France.
| | - Daniel Gillet
- Commissariat à l'Energie Atomique (CEA), Institut de Biologie et Technologies de Saclay (iBiTecS), Service d'Ingénierie Moléculaire des Protéines (SIMOPRO), F-91191 Gif sur Yvette, France.
| |
Collapse
|
11
|
Man P, Montagner C, Vernier G, Dublet B, Chenal A, Forest E, Forge V. Defining the interacting regions between apomyoglobin and lipid membrane by hydrogen/deuterium exchange coupled to mass spectrometry. J Mol Biol 2007; 368:464-72. [PMID: 17346745 DOI: 10.1016/j.jmb.2007.02.014] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2006] [Revised: 01/24/2007] [Accepted: 02/06/2007] [Indexed: 11/22/2022]
Abstract
Sperm whale myoglobin can be considered as the model protein of the globin family. The pH-dependence of the interactions of apomyoglobin with lipid bilayers shares some similarities with the behavior of pore-forming domains of bacterial toxins belonging also to the globin family. Two different states of apomyoglobin bound to a lipid bilayer have been characterized by using hydrogen/deuterium exchange experiments and mass spectrometry. When bound to the membrane at pH 5.5, apomyoglobin remains mostly native-like and interacts through alpha-helix A. At pH 4, the binding is related to the stabilization of a partially folded state. In that case, alpha-helices A and G are involved in the interaction. At this pH, alpha-helix G, which is the most hydrophobic region of apomyoglobin, is available for interaction with the lipid bilayer because of the loss of the tertiary structure. Our results show the feasibility of such experiments and their potential for the characterization of various membrane-bound states of amphitropic proteins such as pore-forming domains of bacterial toxins. This is not possible with other high-resolution methods, because these proteins are usually in partially folded states when interacting with membranes.
Collapse
Affiliation(s)
- Petr Man
- Laboratoire de Spectrométrie de Masse des Protéines, Institut de Biologie Structurale (CEA-CNRS-UJF), 41 rue Jules Horowitz, 38027 Grenoble, France
| | | | | | | | | | | | | |
Collapse
|
12
|
Montagner C, Perier A, Pichard S, Vernier G, Ménez A, Gillet D, Forge V, Chenal A. Behavior of the N-Terminal Helices of the Diphtheria Toxin T Domain during the Successive Steps of Membrane Interaction. Biochemistry 2007; 46:1878-87. [PMID: 17249698 DOI: 10.1021/bi602381z] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [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: 11/29/2022]
Abstract
During intoxication of a cell, the translocation (T) domain of the diphtheria toxin helps the passage of the catalytic domain across the membrane of the endosome into the cytoplasm. We have investigated the behavior of the N-terminal region of the T domain during the successive steps of its interaction with membranes at acidic pH using tryptophan fluorescence, its quenching by brominated lipids, and trypsin digestion. The change in the environment of this region was monitored using mutant W281F carrying a single native tryptophan at position 206 at the tip of helix TH1. The intrinsic propensity to interact with the membrane of each helix of the N-terminus of the T domain, TH1, TH2, TH3, and TH4, was also studied using synthetic peptides. We showed the N-terminal region of the T domain was not involved in the binding of the domain to the membrane, which occurred at pH 6 mainly through hydrophobic effects. At that stage of the interaction, the N-terminal region remained strongly solvated. Further acidification eliminated repulsive electrostatic interactions between this region and the membrane, allowing its penetration into the membrane by attractive electrostatic interactions and hydrophobic effects. The peptide study indicated the nature of forces contributing to membrane penetration. Overall, the data suggested that the acidic pH found in the endosome not only triggers the formation of the molten globule state of the T domain required for membrane interaction but also governs a progressive penetration of the N-terminal part of the T domain in the membrane. We propose that these physicochemical properties are necessary for the translocation of the catalytic domain.
Collapse
Affiliation(s)
- Caroline Montagner
- CEA, DSV, Département Réponse et Dynamique Cellulaires, Biophysique Moléculaire et Cellulaire, UMR 5090, 17 rue des Martyrs, 38054 Grenoble cedex 9, France
| | | | | | | | | | | | | | | |
Collapse
|
13
|
Vernier G, Chenal A, Vitrac H, Barumandzadhe R, Montagner C, Forge V. Interactions of apomyoglobin with membranes: mechanisms and effects on heme uptake. Protein Sci 2007; 16:391-400. [PMID: 17242377 PMCID: PMC2203327 DOI: 10.1110/ps.062531207] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [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: 10/23/2022]
Abstract
The last step of the folding reaction of myoglobin is the incorporation of a prosthetic group. In cells, myoglobin is soluble, while heme resides in the mitochondrial membrane. We report here an exhaustive study of the interactions of apomyoglobin with lipid vesicles. We show that apomyoglobin interacts with large unilamellar vesicles under acidic conditions, and that this requires the presence of negatively charged phospholipids. The pH dependence of apomyoglobin interactions with membranes is a two-step process, and involves a partially folded state stabilized at acidic pH. An evident role for the interaction of apomyoglobin with lipid bilayers would be to facilitate the uptake of heme from the outer mitochondrial membrane. However, heme binding to apomyoglobin is observed at neutral pH when the protein remains in solution, and slows down as the pH becomes more favorable to membrane interactions. The effective incorporation of soluble heme into apomyoglobin at neutral pH suggests that the interaction of apomyoglobin with membranes is not necessary for the heme uptake from the lipid bilayer. In vivo, however, the ability of apomyoglobin to interact with membrane may facilitate its localization in the vicinity of the mitochondrial membranes, and so may increase the yield of heme uptake. Moreover, the behavior of apomyoglobin in the presence of membranes shows striking similarities with that of other proteins with a globin fold. This suggests that the globin fold is well adapted for soluble proteins whose functions require interactions with membranes.
Collapse
Affiliation(s)
- Grégory Vernier
- Laboratoire de Biophysique Moléculaire et Cellulaire, Unité Mixte de Recherche 5090, Département Réponse et Dynamique Cellulaires, CEA-Grenoble, 38054 Grenoble cedex 9, France
| | | | | | | | | | | |
Collapse
|
14
|
Bourgeois P, Benoist M, Palazzo E, Belmatoug N, Folinais D, Frot B, Busson G, Lassale P, Montagner C, Binoche T. [Multicenter randomized double-blind study of triamcinolone hexacetonide versus chymopapain in the treatment of disk lumbosciatica. Initial results at 6 months]. Rev Rhum Mal Osteoartic 1988; 55:767-9. [PMID: 2973652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- P Bourgeois
- Clinique de Rhumatologie, Université de Paris VII, Hôpital Bichat
| | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Steigman J, Verdini AS, Montagner C, Strasorier L. Protonation of peptides. II. The protonation of an amide and of a diamide in dichloroacetic acid, and the behavior of poly-gamma-benzyl-L-glutamate in dichloroacetic acid and in some mixed solvents. J Am Chem Soc 1969; 91:1829-36. [PMID: 5779831 DOI: 10.1021/ja01035a039] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
|