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Brian K. Kobilka - One of the best experts on this subject based on the ideXlab platform.

  • Conformationally Preorganized Diastereomeric Norbornane-Based Maltosides for Membrane Protein Study: Implications of Detergent Kink for Micellar Properties
    Journal of the American Chemical Society, 2017
    Co-Authors: Manabendra Das, Orquidea Ribeiro, Parameswaran Hariharan, Jonas S. Mortensen, Dhabaleswar Patra, Georgios Skiniotis, Claus J. Loland, Lan Guan, Brian K. Kobilka
    Abstract:

    Detergents are essential tools for functional and structural studies of membrane proteins. However, conventional detergents are limited in their scope and utility, particularly for eukaryotic membrane proteins. Thus, there are major efforts to develop new amphipathic agents with enhanced properties. Here, a novel class of diastereomeric agents with a preorganized conformation, designated norbornane-based Maltosides (NBMs), were prepared and evaluated for their ability to solubilize and stabilize membrane proteins. Representative NBMs displayed enhanced behaviors compared to n-dodecyl-β-d-maltoside (DDM) for all membrane proteins tested. Efficacy of the individual NBMs varied depending on the overall detergent shape and alkyl chain length. Specifically, NBMs with no kink in the lipophilic region conferred greater stability to the proteins than NBMs with a kink. In addition, long alkyl chain NBMs were generally better at stabilizing membrane proteins than short alkyl chain agents. Furthermore, use of one we...

  • Conformationally Preorganized Diastereomeric Norbornane-Based Maltosides for Membrane Protein Study: Implications of Detergent Kink for Micellar Properties
    2017
    Co-Authors: Manabendra Das, Orquidea Ribeiro, Parameswaran Hariharan, Jonas S. Mortensen, Dhabaleswar Patra, Georgios Skiniotis, Claus J. Loland, Lan Guan, Brian K. Kobilka
    Abstract:

    Detergents are essential tools for functional and structural studies of membrane proteins. However, conventional detergents are limited in their scope and utility, particularly for eukaryotic membrane proteins. Thus, there are major efforts to develop new amphipathic agents with enhanced properties. Here, a novel class of diastereomeric agents with a preorganized conformation, designated norbornane-based Maltosides (NBMs), were prepared and evaluated for their ability to solubilize and stabilize membrane proteins. Representative NBMs displayed enhanced behaviors compared to n-dodecyl-β-d-maltoside (DDM) for all membrane proteins tested. Efficacy of the individual NBMs varied depending on the overall detergent shape and alkyl chain length. Specifically, NBMs with no kink in the lipophilic region conferred greater stability to the proteins than NBMs with a kink. In addition, long alkyl chain NBMs were generally better at stabilizing membrane proteins than short alkyl chain agents. Furthermore, use of one well-behaving NBM enabled us to attain a marked stabilization and clear visualization of a challenging membrane protein complex using electron microscopy. Thus, this study not only describes novel maltoside detergents with enhanced protein-stabilizing properties but also suggests that overall detergent geometry has an important role in determining membrane protein stability. Notably, this is the first systematic study on the effect of detergent kinking on micellar properties and associated membrane protein stability

  • Conformationally Preorganized Diastereomeric Norbornane-Based Maltosides for Membrane Protein Study: Implications of Detergent Kink for Micellar Properties
    'American Chemical Society (ACS)', 2017
    Co-Authors: Das M, Claus J. Loland, Du Y, Ribeiro O, Hariharan P, Js Mortensen, Patra D, Skiniotis G, Guan L, Brian K. Kobilka
    Abstract:

    Detergents are essential tools for functional and structural studies of membrane proteins. However, conventional detergents are limited in their scope and utility, particularly for eukaryotic membrane proteins. Thus, there are major efforts to develop new amphipathic agents with enhanced properties. Here, a novel class of diastereomeric agents with a preorganized conformation, designated norbornane-based Maltosides (NBMs), were prepared and evaluated for their ability to solubilize and stabilize membrane proteins. Representative NBMs displayed enhanced behaviors compared to n-dodecyl-β-d-maltoside (DDM) for all membrane proteins tested. Efficacy of the individual NBMs varied depending on the overall detergent shape and alkyl chain length. Specifically, NBMs with no kink in the lipophilic region conferred greater stability to the proteins than NBMs with a kink. In addition, long alkyl chain NBMs were generally better at stabilizing membrane proteins than short alkyl chain agents. Furthermore, use of one well-behaving NBM enabled us to attain a marked stabilization and clear visualization of a challenging membrane protein complex using electron microscopy. Thus, this study not only describes novel maltoside detergents with enhanced protein-stabilizing properties but also suggests that overall detergent geometry has an important role in determining membrane protein stability. Notably, this is the first systematic study on the effect of detergent kinking on micellar properties and associated membrane protein stability

  • Tandem neopentyl glycol Maltosides (TNMs) for membrane protein stabilisation
    Chemical communications (Cambridge England), 2016
    Co-Authors: Hyoung Eun Bae, Orquidea Ribeiro, Jonas S. Mortensen, Claus J. Loland, Brian K. Kobilka, Muhammad Ali Ehsan, Bernadette Byrne, Pil Seok Chae
    Abstract:

    A novel class of detergents, designated tandem neopentyl glycol Maltosides (TNMs), were evaluated with four target membrane proteins. The best detergent varied depending on the target, but TNM-C12L and TNM-C11S were notable for their ability to confer increased membrane protein stability compared to DDM. These agents have potential for use in membrane protein research.

  • Novel Xylene‐Linked Maltoside Amphiphiles (XMAs) for Membrane Protein Stabilisation
    Chemistry (Weinheim an der Bergstrasse Germany), 2015
    Co-Authors: Kyung Ho Cho, Parameswaran Hariharan, Claus J. Loland, Lan Guan, Brian K. Kobilka, Bernadette Byrne, Nicola J. Scull, Kamil Gotfryd, Pil Seok Chae
    Abstract:

    Membrane proteins are key functional players in biological systems. These biomacromolecules contain both hydrophilic and hydrophobic regions and thus amphipathic molecules are necessary to extract membrane proteins from their native lipid environments and stabilise them in aqueous solutions. Conventional detergents are commonly used for membrane protein manipulation, but membrane proteins surrounded by these agents often undergo denaturation and aggregation. In this study, a novel class of maltoside-bearing amphiphiles, with a xylene linker in the central region, designated xylene-linked maltoside amphiphiles (XMAs) was developed. When these novel agents were evaluated with a number of membrane proteins, it was found that XMA-4 and XMA-5 have particularly favourable efficacy with respect to membrane protein stabilisation, indicating that these agents hold significant potential for membrane protein structural study.

P. Somasundaran - One of the best experts on this subject based on the ideXlab platform.

  • Adsorption of mixtures of nonionic sugar-based surfactants with other surfactants at solid/liquid interfaces II. Adsorption of n-dodecyl-β-D-maltoside with a cationic surfactant and a nonionic ethoxylated surfactant on solids
    Journal of colloid and interface science, 2006
    Co-Authors: Lei Zhang, Rui Zhang, P. Somasundaran
    Abstract:

    Synergy and antagonism between sugar-based surfactants, a group of environmentally benign surfactants, and cationic surfactants and nonionic ethoxylated surfactants have been investigated in this study with solids which adsorbs only one or other when presented alone. Sugar-based n-dodecyl-β-D-maltoside (DM) does not adsorb on silica by itself. However, in mixtures with cationic dodecyltrimethylammonium bromide (DTAB) and nonionic nonylphenol ethoxylated decyl ether (NP-10), DM adsorbs on silica through hydrophobic interactions. In contrast, although DM does adsorb on alumina, the presence of NP-10 reduces the adsorption of DM as well as that of the total surfactant adsorption. Such synergistic/antagonistic effects of sugar-based n-dodecyl-β-D-maltoside (DM) in mixtures with other surfactants at solid/liquid interfaces were systematically investigated and some general rules on synergy/antagonism in mixed surfactant systems are identified. These results have implications for designing surfactant combinations for controlled adsorption or prevention of adsorption.

  • Study of mixtures of n-dodecyl-β-d-maltoside with anionic, cationic, and nonionic surfactant in aqueous solutions using surface tension and fluorescence techniques
    Journal of colloid and interface science, 2004
    Co-Authors: Rui Zhang, Lei Zhang, P. Somasundaran
    Abstract:

    Abstract Surfactants of practical interest are invariably mixtures of different types. In this study, mixtures of sugar-based n-dodecyl-β- d -maltoside with cationic dodecyltrimethylammonium bromide, anionic sodium dodecylsulfate, and nonionic pentaethyleneglycol monododecyl ether in solution, with and without supporting electrolyte, have been studied using surface tension and fluorescence spectroscopic techniques. Interaction parameters and mole fraction of components in mixed micelles were calculated using regular solution theory. The magnitude of interactions between n-dodecyl-β- d -maltoside and other surfactants followed the order anionic/nonionic > cationic/nonionic > nonionic/nonionic mixtures. Since all surfactants have the same hydrophobic groups, strengths of interactions are attributed to the structures of hydrophilic headgroups. Electrolyte reduced synergism between n-dodecyl-β- d -maltoside and ionic surfactant due to charge neutralization. Industrial sugar-based surfactant, dodecyl polyglucoside, yielded results similar to that with dodecyl maltoside, implying that tested commercial alkyl polyglucosides are similar to the pure laboratory samples in synergistic interactions with other surfactants. Fluorescence study not only supported the cmc results using tensiometry, but showed that interfaces of all the above mixed micelle/solution interfaces are mildly hydrophobic. Based on these results, an attempt is made to discover the nature of interactions to be a combination of intermolecular potential energies and free energy due to packing of surfactant molecules in micelles.

  • Structure of adsorbed n-dodecyl-β-D-maltoside layers on hematite
    Journal of colloid and interface science, 2004
    Co-Authors: E. Mielczarski, Jerzy A. Mielczarski, Lei Zhang, P. Somasundaran
    Abstract:

    The composition, structure, and thickness of n-dodecyl-β-D-maltoside self-assembled layers on hematite have been evaluated using infrared external reflection spectroscopy and spectral simulation techniques. From the qualitative and quantitative analysis of the reflection spectra of the same sample recorded at different specific angles of incidence and two polarizations, the orientation of the sugar ring and hydrocarbon chain were obtained. Both of these molecular groups are positioned parallel to hematite surface, the adsorbed molecules being at low (2.2-nm-thick layer) as well as higher (11-nm) coverages. The maltoside is adsorbed through interaction of sugar ring OH groups with hematite surface hydroxyl groups. The adsorption of maltoside is not very strong and desorption takes place easily from acidic and low-basic solutions but with more difficulty from strong-basic solution.

  • Adsorption Mechanism of n-dodecyl-β-D-maltoside on Alumina
    Journal of Colloid and Interface Science, 2002
    Co-Authors: Lei Zhang, Jerzy A. Mielczarski, P. Somasundaran, E. Mielczarski
    Abstract:

    Adsorption/desorption behavior of a sugar-based surfactant, n-dodecyl-β-D-maltoside, on alumina has been studied and mechanisms involved explored. The surfactant behaves quite differently from nonionic ethoxylated surfactants. In this study, adsorption/desorption of n-dodecyl-β-D-maltoside on alumina under different solution conditions (pH and temperature) and in hydrogen bond disrupters (urea and DMSO) was investigated. Electrokinetic measurements of the solid after surfactant adsorption were also carried out. Metal ion–surfactant interactions, as well as maltose–alumina interactions in solution was examined. No evidence of electrostatic interaction or chemical interaction was found between the surfactant and the solid. This is confirmed by the FTIR spectroscopic studies. It is concluded that weak interaction, namely hydrogen bonding, is the main driving force for the adsorption. The results are discussed in terms of the solid and solution properties as well as interactions between the solid and surfactant.

  • Adsorption ofn-Dodecyl-β-d-maltoside on Solids
    Journal of colloid and interface science, 1997
    Co-Authors: Lei Zhang, P. Somasundaran, C. Maltesh
    Abstract:

    Adsorption of a typical sugar-based surfactant,n-dodecyl-β-d-maltoside (DM), on hydrophilic solids, silica, alumina, titania, and hematite, and a hydrophobic solid, graphite, was studied. Effects of salts and pH on the adsorption on alumina as well as the electrokinetic potential of the particles after surfactant adsorption were studied to determine the adsorption mechanisms. Hydrophobicity and settling rate were measured to explore the surfactant conformation on the particle surfaces. For hydrophilic solids, DM was found to adsorb strongly on alumina, titania, and hematite but weakly on silica. While hydrogen bonding is postulated to be the major driving force for the adsorption on hydrophilic solids, for hydrophobic solid, the adsorption is mainly due to the hydrophobic interactions. The different behaviors of surfactant on hydrophilic and hydrophobic solids were attributed to the different interactions between surfactant and solids. Also, the surfactant is estimated to form a bilayer on alumina while on graphite it forms a monolayer. The surface hydrophobicity and stability of the solids are discussed in terms of the adsorbed monolayer/bilayer formation on the particles.

Osigwe Esue - One of the best experts on this subject based on the ideXlab platform.

  • Hexyl Glucoside and Hexyl Maltoside Inhibit Light‐Induced Oxidation of Tryptophan
    Journal of Pharmaceutical Sciences, 2013
    Co-Authors: Yilma T. Adem, Patricia Molina, Alavattam Sreedhara, Thomas W Patapoff, Osigwe Esue
    Abstract:

    We investigated the photo-protective effect of sugar-based surfactants—hexyl glucoside and hexyl maltoside—against light-induced oxidation of a monoclonal antibody. Reactive oxygen species are generated in solutions in the presence of light; these reactive species readily oxidize amino acids such as tryptophan. Hexyl glucosides and hexyl Maltosides scavenge these reactive species and protect tryptophan residues from light-induced oxidation in a concentration-dependent manner. As a result of the scavenging process, hydrogen peroxide is formed, especially at high (millimolar) concentrations of the alkyl glycoside surfactants. These results suggest that hexyl glucoside and hexyl maltoside have the potential to protect tryptophan residues against light-induced oxidation. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 103:409–416, 2014

  • Hexyl glucoside and hexyl maltoside inhibit light-induced oxidation of tryptophan.
    Journal of pharmaceutical sciences, 2013
    Co-Authors: Yilma T. Adem, Patricia Molina, Alavattam Sreedhara, Thomas W Patapoff, Hongbin Liu, Osigwe Esue
    Abstract:

    We investigated the photo-protective effect of sugar-based surfactants—hexyl glucoside and hexyl maltoside—against light-induced oxidation of a monoclonal antibody. Reactive oxygen species are generated in solutions in the presence of light; these reactive species readily oxidize amino acids such as tryptophan. Hexyl glucosides and hexyl Maltosides scavenge these reactive species and protect tryptophan residues from light-induced oxidation in a concentration-dependent manner. As a result of the scavenging process, hydrogen peroxide is formed, especially at high (millimolar) concentrations of the alkyl glycoside surfactants. These results suggest that hexyl glucoside and hexyl maltoside have the potential to protect tryptophan residues against light-induced oxidation. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 103:409–416, 2014

Lei Zhang - One of the best experts on this subject based on the ideXlab platform.

  • Adsorption of mixtures of nonionic sugar-based surfactants with other surfactants at solid/liquid interfaces II. Adsorption of n-dodecyl-β-D-maltoside with a cationic surfactant and a nonionic ethoxylated surfactant on solids
    Journal of colloid and interface science, 2006
    Co-Authors: Lei Zhang, Rui Zhang, P. Somasundaran
    Abstract:

    Synergy and antagonism between sugar-based surfactants, a group of environmentally benign surfactants, and cationic surfactants and nonionic ethoxylated surfactants have been investigated in this study with solids which adsorbs only one or other when presented alone. Sugar-based n-dodecyl-β-D-maltoside (DM) does not adsorb on silica by itself. However, in mixtures with cationic dodecyltrimethylammonium bromide (DTAB) and nonionic nonylphenol ethoxylated decyl ether (NP-10), DM adsorbs on silica through hydrophobic interactions. In contrast, although DM does adsorb on alumina, the presence of NP-10 reduces the adsorption of DM as well as that of the total surfactant adsorption. Such synergistic/antagonistic effects of sugar-based n-dodecyl-β-D-maltoside (DM) in mixtures with other surfactants at solid/liquid interfaces were systematically investigated and some general rules on synergy/antagonism in mixed surfactant systems are identified. These results have implications for designing surfactant combinations for controlled adsorption or prevention of adsorption.

  • Study of mixtures of n-dodecyl-β-d-maltoside with anionic, cationic, and nonionic surfactant in aqueous solutions using surface tension and fluorescence techniques
    Journal of colloid and interface science, 2004
    Co-Authors: Rui Zhang, Lei Zhang, P. Somasundaran
    Abstract:

    Abstract Surfactants of practical interest are invariably mixtures of different types. In this study, mixtures of sugar-based n-dodecyl-β- d -maltoside with cationic dodecyltrimethylammonium bromide, anionic sodium dodecylsulfate, and nonionic pentaethyleneglycol monododecyl ether in solution, with and without supporting electrolyte, have been studied using surface tension and fluorescence spectroscopic techniques. Interaction parameters and mole fraction of components in mixed micelles were calculated using regular solution theory. The magnitude of interactions between n-dodecyl-β- d -maltoside and other surfactants followed the order anionic/nonionic > cationic/nonionic > nonionic/nonionic mixtures. Since all surfactants have the same hydrophobic groups, strengths of interactions are attributed to the structures of hydrophilic headgroups. Electrolyte reduced synergism between n-dodecyl-β- d -maltoside and ionic surfactant due to charge neutralization. Industrial sugar-based surfactant, dodecyl polyglucoside, yielded results similar to that with dodecyl maltoside, implying that tested commercial alkyl polyglucosides are similar to the pure laboratory samples in synergistic interactions with other surfactants. Fluorescence study not only supported the cmc results using tensiometry, but showed that interfaces of all the above mixed micelle/solution interfaces are mildly hydrophobic. Based on these results, an attempt is made to discover the nature of interactions to be a combination of intermolecular potential energies and free energy due to packing of surfactant molecules in micelles.

  • Structure of adsorbed n-dodecyl-β-D-maltoside layers on hematite
    Journal of colloid and interface science, 2004
    Co-Authors: E. Mielczarski, Jerzy A. Mielczarski, Lei Zhang, P. Somasundaran
    Abstract:

    The composition, structure, and thickness of n-dodecyl-β-D-maltoside self-assembled layers on hematite have been evaluated using infrared external reflection spectroscopy and spectral simulation techniques. From the qualitative and quantitative analysis of the reflection spectra of the same sample recorded at different specific angles of incidence and two polarizations, the orientation of the sugar ring and hydrocarbon chain were obtained. Both of these molecular groups are positioned parallel to hematite surface, the adsorbed molecules being at low (2.2-nm-thick layer) as well as higher (11-nm) coverages. The maltoside is adsorbed through interaction of sugar ring OH groups with hematite surface hydroxyl groups. The adsorption of maltoside is not very strong and desorption takes place easily from acidic and low-basic solutions but with more difficulty from strong-basic solution.

  • Adsorption Mechanism of n-dodecyl-β-D-maltoside on Alumina
    Journal of Colloid and Interface Science, 2002
    Co-Authors: Lei Zhang, Jerzy A. Mielczarski, P. Somasundaran, E. Mielczarski
    Abstract:

    Adsorption/desorption behavior of a sugar-based surfactant, n-dodecyl-β-D-maltoside, on alumina has been studied and mechanisms involved explored. The surfactant behaves quite differently from nonionic ethoxylated surfactants. In this study, adsorption/desorption of n-dodecyl-β-D-maltoside on alumina under different solution conditions (pH and temperature) and in hydrogen bond disrupters (urea and DMSO) was investigated. Electrokinetic measurements of the solid after surfactant adsorption were also carried out. Metal ion–surfactant interactions, as well as maltose–alumina interactions in solution was examined. No evidence of electrostatic interaction or chemical interaction was found between the surfactant and the solid. This is confirmed by the FTIR spectroscopic studies. It is concluded that weak interaction, namely hydrogen bonding, is the main driving force for the adsorption. The results are discussed in terms of the solid and solution properties as well as interactions between the solid and surfactant.

  • Adsorption ofn-Dodecyl-β-d-maltoside on Solids
    Journal of colloid and interface science, 1997
    Co-Authors: Lei Zhang, P. Somasundaran, C. Maltesh
    Abstract:

    Adsorption of a typical sugar-based surfactant,n-dodecyl-β-d-maltoside (DM), on hydrophilic solids, silica, alumina, titania, and hematite, and a hydrophobic solid, graphite, was studied. Effects of salts and pH on the adsorption on alumina as well as the electrokinetic potential of the particles after surfactant adsorption were studied to determine the adsorption mechanisms. Hydrophobicity and settling rate were measured to explore the surfactant conformation on the particle surfaces. For hydrophilic solids, DM was found to adsorb strongly on alumina, titania, and hematite but weakly on silica. While hydrogen bonding is postulated to be the major driving force for the adsorption on hydrophilic solids, for hydrophobic solid, the adsorption is mainly due to the hydrophobic interactions. The different behaviors of surfactant on hydrophilic and hydrophobic solids were attributed to the different interactions between surfactant and solids. Also, the surfactant is estimated to form a bilayer on alumina while on graphite it forms a monolayer. The surface hydrophobicity and stability of the solids are discussed in terms of the adsorbed monolayer/bilayer formation on the particles.

Yilma T. Adem - One of the best experts on this subject based on the ideXlab platform.

  • Hexyl Glucoside and Hexyl Maltoside Inhibit Light‐Induced Oxidation of Tryptophan
    Journal of Pharmaceutical Sciences, 2013
    Co-Authors: Yilma T. Adem, Patricia Molina, Alavattam Sreedhara, Thomas W Patapoff, Osigwe Esue
    Abstract:

    We investigated the photo-protective effect of sugar-based surfactants—hexyl glucoside and hexyl maltoside—against light-induced oxidation of a monoclonal antibody. Reactive oxygen species are generated in solutions in the presence of light; these reactive species readily oxidize amino acids such as tryptophan. Hexyl glucosides and hexyl Maltosides scavenge these reactive species and protect tryptophan residues from light-induced oxidation in a concentration-dependent manner. As a result of the scavenging process, hydrogen peroxide is formed, especially at high (millimolar) concentrations of the alkyl glycoside surfactants. These results suggest that hexyl glucoside and hexyl maltoside have the potential to protect tryptophan residues against light-induced oxidation. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 103:409–416, 2014

  • Hexyl glucoside and hexyl maltoside inhibit light-induced oxidation of tryptophan.
    Journal of pharmaceutical sciences, 2013
    Co-Authors: Yilma T. Adem, Patricia Molina, Alavattam Sreedhara, Thomas W Patapoff, Hongbin Liu, Osigwe Esue
    Abstract:

    We investigated the photo-protective effect of sugar-based surfactants—hexyl glucoside and hexyl maltoside—against light-induced oxidation of a monoclonal antibody. Reactive oxygen species are generated in solutions in the presence of light; these reactive species readily oxidize amino acids such as tryptophan. Hexyl glucosides and hexyl Maltosides scavenge these reactive species and protect tryptophan residues from light-induced oxidation in a concentration-dependent manner. As a result of the scavenging process, hydrogen peroxide is formed, especially at high (millimolar) concentrations of the alkyl glycoside surfactants. These results suggest that hexyl glucoside and hexyl maltoside have the potential to protect tryptophan residues against light-induced oxidation. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 103:409–416, 2014