20 research outputs found
Selective and WashâResistant Fluorescent Dihydrocodeinone Derivatives Allow SingleâMolecule Imaging of ÎŒâOpioid Receptor Dimerization
ÎŒâOpioid receptors (ÎŒâORs) play a critical role in the modulation of pain and mediate the effects of the most powerful analgesic drugs. Despite extensive efforts, it remains insufficiently understood how ÎŒâORs produce specific effects in living cells. We developed new fluorescent ligands based on the ÎŒâOR antagonist Eâpânitrocinnamoylaminoâdihydrocodeinone (CACO), that display high affinity, long residence time and pronounced selectivity. Using these ligands, we achieved singleâmolecule imaging of ÎŒâORs on the surface of living cells at physiological expression levels. Our results reveal a high heterogeneity in the diffusion of ÎŒâORs, with a relevant immobile fraction. Using a pair of fluorescent ligands of different color, we provide evidence that ÎŒâORs interact with each other to form shortâlived homodimers on the plasma membrane. This approach provides a new strategy to investigate ÎŒâOR pharmacology at singleâmolecule level
How Detergent Impacts Membrane Proteins: Atomic-Level Views of Mitochondrial Carriers in Dodecylphosphocholine.
Characterizing the structure of membrane proteins (MPs) generally requires extraction from their native environment, most commonly with detergents. Yet, the physicochemical properties of detergent micelles and lipid bilayers differ markedly and could alter the structural organization of MPs, albeit without general rules. Dodecylphosphocholine (DPC) is the most widely used detergent for MP structure determination by NMR, but the physiological relevance of several prominent structures has been questioned, though indirectly, by other biophysical techniques, e.g., functional/thermostability assay (TSA) and molecular dynamics (MD) simulations. Here, we resolve unambiguously this controversy by probing the functional relevance of three different mitochondrial carriers (MCs) in DPC at the atomic level, using an exhaustive set of solution-NMR experiments, complemented by functional/TSA and MD data. Our results provide atomic-level insight into the structure, substrate interaction and dynamics of the detergent-membrane protein complexes and demonstrates cogently that, while high-resolution NMR signals can be obtained for MCs in DPC, they systematically correspond to nonfunctional states
Protonation spécifique des méthyles : un outil pour l'étude structurale des assemblages moléculaires par Résonance Magnétique Nucléaires
Standard NMR methods applied to the structural analysis of proteins are based on the measurement of local geometric information between protons. The lack of long range restraints can be limiting factor for the study of the modular proteins, protein complexes and supramolecular assemblies. Perdeuteration of samples is necessary for the study of these large systems. However, the exchange of protons with deuterium limit the number of detectable structural restraints, particularly NOEs distance restraints. To resolve this problem, a strategy based on the protonation of some discrete sites was developed. The specific protonation of methyls in proteins constitutes an optimum choice for detection of long range restraints. Protocols for specific labelling of methyls of Isoleucines, Valines and Leucines were implemented and optimized, and a new method for specific protonation of Alanines was introduced. In moderate size systems, the use of this specific labelling strategy combined with the development of NMR experiments allows the detection of restraints (NOEs and RDCs) between methyls separated by more than 12 Ă
. A robust method was developed to extract distances with very high precision. This approach can also be applied to large proteins. NOEs have been observed between methyls separated by more than 7 Ă
in a 468 kDa supramolecular assembly.Les mĂ©thodes RMN standard appliquĂ©es Ă l'analyse structurale des protĂ©ines sont basĂ©es sur la mesure d'informations gĂ©omĂ©triques locales entre protons. Le manque de contraintes Ă longue portĂ©e est un facteur limitant pour l'Ă©tude des protĂ©ines modulaires, des complexes protĂ©iques et des assemblages supramolĂ©culaires. La deutĂ©ration des Ă©chantillons est nĂ©cessaire pour l'Ă©tude de ces systĂšmes de grande taille. NĂ©anmoins, le remplacement des protons par du deutĂ©rium limite le nombre de contraintes structurales dĂ©tectables, en particulier des contraintes de distances de types NOEs. Pour rĂ©soudre ce problĂšme, une stratĂ©gie basĂ©e sur la protonation de quelques sites discrets a Ă©tĂ© mise en place. La protonation spĂ©cifique des mĂ©thyles dans des protĂ©ines constitue un choix optimal pour l'obtention de contraintes Ă longue portĂ©e. Les protocoles de marquage spĂ©cifique des mĂ©thyles des Isoleucines, des Valines et des Leucines ont Ă©tĂ© implĂ©mentĂ©s et optimisĂ©s, et une nouvelle mĂ©thode de protonation spĂ©cifique des Alanines a Ă©tĂ© dĂ©veloppĂ©e. Dans des systĂšmes de taille modĂ©rĂ©e, l'utilisation de ce type de marquage combinĂ© aux dĂ©veloppements d'expĂ©riences RMN adaptĂ©es permet la dĂ©tection de contraintes (NOEs et RDCs) entre paire de mĂ©thyles sĂ©parĂ©s par plus de 12 Ă
. Une mĂ©thode robuste a Ă©tĂ© dĂ©veloppĂ©e pour extraire des distances avec une trĂšs haute prĂ©cision. Cette approche s'applique Ă©galement Ă des protĂ©ines de grande taille, ainsi des NOEs entre mĂ©thyles distants par plus de 7 Ă
sont détecté dans un assemblage supramoléculaire de 468 kDa
Protonation spécifique des méthyles : un outil pour l'étude structurale des assemblages moléculaires par Résonance Magnétique Nucléaires
Standard NMR methods applied to the structural analysis of proteins are based on the measurement of local geometric information between protons. The lack of long range restraints can be limiting factor for the study of the modular proteins, protein complexes and supramolecular assemblies. Perdeuteration of samples is necessary for the study of these large systems. However, the exchange of protons with deuterium limit the number of detectable structural restraints, particularly NOEs distance restraints. To resolve this problem, a strategy based on the protonation of some discrete sites was developed. The specific protonation of methyls in proteins constitutes an optimum choice for detection of long range restraints. Protocols for specific labelling of methyls of Isoleucines, Valines and Leucines were implemented and optimized, and a new method for specific protonation of Alanines was introduced. In moderate size systems, the use of this specific labelling strategy combined with the development of NMR experiments allows the detection of restraints (NOEs and RDCs) between methyls separated by more than 12 Ă
. A robust method was developed to extract distances with very high precision. This approach can also be applied to large proteins. NOEs have been observed between methyls separated by more than 7 Ă
in a 468 kDa supramolecular assembly.Les mĂ©thodes RMN standard appliquĂ©es Ă l'analyse structurale des protĂ©ines sont basĂ©es sur la mesure d'informations gĂ©omĂ©triques locales entre protons. Le manque de contraintes Ă longue portĂ©e est un facteur limitant pour l'Ă©tude des protĂ©ines modulaires, des complexes protĂ©iques et des assemblages supramolĂ©culaires. La deutĂ©ration des Ă©chantillons est nĂ©cessaire pour l'Ă©tude de ces systĂšmes de grande taille. NĂ©anmoins, le remplacement des protons par du deutĂ©rium limite le nombre de contraintes structurales dĂ©tectables, en particulier des contraintes de distances de types NOEs. Pour rĂ©soudre ce problĂšme, une stratĂ©gie basĂ©e sur la protonation de quelques sites discrets a Ă©tĂ© mise en place. La protonation spĂ©cifique des mĂ©thyles dans des protĂ©ines constitue un choix optimal pour l'obtention de contraintes Ă longue portĂ©e. Les protocoles de marquage spĂ©cifique des mĂ©thyles des Isoleucines, des Valines et des Leucines ont Ă©tĂ© implĂ©mentĂ©s et optimisĂ©s, et une nouvelle mĂ©thode de protonation spĂ©cifique des Alanines a Ă©tĂ© dĂ©veloppĂ©e. Dans des systĂšmes de taille modĂ©rĂ©e, l'utilisation de ce type de marquage combinĂ© aux dĂ©veloppements d'expĂ©riences RMN adaptĂ©es permet la dĂ©tection de contraintes (NOEs et RDCs) entre paire de mĂ©thyles sĂ©parĂ©s par plus de 12 Ă
. Une mĂ©thode robuste a Ă©tĂ© dĂ©veloppĂ©e pour extraire des distances avec une trĂšs haute prĂ©cision. Cette approche s'applique Ă©galement Ă des protĂ©ines de grande taille, ainsi des NOEs entre mĂ©thyles distants par plus de 7 Ă
sont détecté dans un assemblage supramoléculaire de 468 kDa
Protonation specifique des methyles ( un outil pour l étude structurale des assemblages moléculaires par résonance magnétique nucléaire )
Les mĂ©thodes RMN standard appliquĂ©es Ă l'analyse structurale des protĂ©ines sont basĂ©es sur la mesure d'informations gĂ©omĂ©triques locales entre protons. Le manque de contraintes Ă longue portĂ©e est un facteur limitant pour l'Ă©tude des protĂ©ines modulaires, des complexes protĂ©iques et des assemblages supramolĂ©culaires. La deutĂ©ration des Ă©chantillons est nĂ©cessaire pour l'Ă©tude de ces systĂšmes de grande taille. NĂ©anmoins, le remplacement des protons par du deutĂ©rium limite le nombre de contraintes structurales dĂ©tectables, en particulier des contraintes de distances de types NOEs. Pour rĂ©soudre ce problĂšme, une stratĂ©gie basĂ©e sur la protonation de quelques sites discrets a Ă©tĂ© mise en place. La protonation spĂ©cifique des mĂ©thyles dans des protĂ©ines constitue un choix optimal pour l'obtention de contraintes Ă longue portĂ©e. Les protocoles de marquage spĂ©cifique des mĂ©thyles des Isoleucines, des Valines et des Leucines ont Ă©tĂ© implĂ©mentĂ©s et optimisĂ©s, et une nouvelle mĂ©thode de protonation spĂ©cifique des Alanines a Ă©tĂ© dĂ©veloppĂ©e. Dans des systĂšmes de taille modĂ©rĂ©e, l'utilisation de ce type de marquage combinĂ© aux dĂ©veloppements d'expĂ©riences RMN adaptĂ©es permet la dĂ©tection de contraintes (NOEs et ROCs) entre paire de mĂ©thyles sĂ©parĂ©s par plus de 12 A. Une mĂ©thode robuste a Ă©tĂ© dĂ©veloppĂ©e pour extraire des distances avec une trĂšs haute prĂ©cision. Cette approche s'applique Ă©galement Ă des protĂ©ines de grande taille, ainsi des NOEs entre mĂ©thyles distants par plus de 7 A sont dĂ©tectĂ© dans un assemblage supramolĂ©culaire de 468 kDa.Standard NMR methods applied to the structural analysis of proteins are based on the measurement of local geometric information between protons. The lack of long range restraints can be limiting factor for the study of the modular proteins, protein complexes and supramolecular assemblies. Perdeuteration of samples is necessary for the study of these large systems. However, the exchange of protons with deuterium limit the number of detectable structural restraints, particularly NOEs distance restraints. To resolve this problem, a strategy based on the protonation of sorne discrete sites was developed. The specific protonation of methyls in proteins constitutes an optimum choice for detection of long range restraints. Protocols for specific labelling of methyls of Isoleucines, Valines and Leucines were implemented and optimized, and a new method for specific protonation of Alanines was introduced. ln moderate size systems, the use of this specific labelling strategy combined with the development of NMR experiments allows the detection of restraints (NOEs and RDCs) between methyls separated by more than 12 Ă. A robust method was developed to extract distances with very high precision. This approach can also be applied to large proteins. NOEs have been observed between methyls separated by more than 7 Ă in a 468 kDa supramolecular assembly.GRENOBLE1-BU Sciences (384212103) / SudocSudocFranceF
1H, 13C and 15N backbone chemical shift assignments of camelid single-domain antibodies against active state ”-opioid receptor
International audienceNanobodies are single chain antibodies that have become a highly valuable and versatile tool for biomolecular and therapeutic research. One application field is the stabilization of active states of flexible proteins, among which G-protein coupled receptors (GPCRs) represent a very important class of membrane proteins. Here we present the backbone and side-chain assignment of the 1H, 13C and 15N resonances of Nb33 and Nb39, two nanobodies that recognize and stabilize the Ό-opioid receptor (ΌOR) to opioids in its active agonist-bound conformation. In addition, we present a comparison of their secondary structures as derived from NMR chemical shifts
Methyl-specific isotopic labeling: a molecular tool box for solution NMR studies of large proteins.
International audienceNuclear magnetic resonance (NMR) spectroscopy is a uniquely powerful tool for studying the structure, dynamics and interactions of biomolecules at atomic resolution. In the past 15 years, the development of new isotopic labeling strategies has opened the possibility of exploiting NMR spectroscopy in the study of supra-molecular complexes with molecular weights of up to 1 MDa. At the core of these isotopic labeling developments is the specific introduction of [1H,13C]-labeled methyl probes into perdeuterated proteins. Here, we describe the evolution of these approaches and discuss their impact on structural and biological studies. The relevant protocols are succinctly reviewed for single and combinatorial isotopic-labeling of methyl-containing residues, and examples of applications on challenging biological systems, including high molecular weight and membrane proteins, are presented
Sensitivity-optimized experiment for the measurement of residual dipolar couplings between amide protons
International audienc