1
|
Liu F, Greenwood AI, Xiong Y, Miceli RT, Fu R, Anderson KW, McCallum SA, Mihailescu M, Gross R, Cotten ML. Host Defense Peptide Piscidin and Yeast-Derived Glycolipid Exhibit Synergistic Antimicrobial Action through Concerted Interactions with Membranes. JACS AU 2023; 3:3345-3365. [PMID: 38155643 PMCID: PMC10751773 DOI: 10.1021/jacsau.3c00506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Revised: 09/25/2023] [Accepted: 09/29/2023] [Indexed: 12/30/2023]
Abstract
Developing new antimicrobials as alternatives to conventional antibiotics has become an urgent race to eradicate drug-resistant bacteria and to save human lives. Conventionally, antimicrobial molecules are studied independently even though they can be cosecreted in vivo. In this research, we investigate two classes of naturally derived antimicrobials: sophorolipid (SL) esters as modified yeast-derived glycolipid biosurfactants that feature high biocompatibility and low production cost; piscidins, which are host defense peptides (HDPs) from fish. While HDPs such as piscidins target the membrane of pathogens, and thus result in low incidence of resistance, SLs are not well understood on a mechanistic level. Here, we demonstrate that combining SL-hexyl ester (SL-HE) with subinhibitory concentration of piscidins 1 (P1) and 3 (P3) stimulates strong antimicrobial synergy, potentiating a promising therapeutic window. Permeabilization assays and biophysical studies employing circular dichroism, NMR, mass spectrometry, and X-ray diffraction are performed to investigate the mechanism underlying this powerful synergy. We reveal four key mechanistic features underlying the synergistic action: (1) P1/3 binds to SL-HE aggregates, becoming α-helical; (2) piscidin-glycolipid assemblies synergistically accumulate on membranes; (3) SL-HE used alone or bound to P1/3 associates with phospholipid bilayers where it induces defects; (4) piscidin-glycolipid complexes disrupt the bilayer structure more dramatically and differently than either compound alone, with phase separation occurring when both agents are present. Overall, dramatic enhancement in antimicrobial activity is associated with the use of two membrane-active agents, with the glycolipid playing the roles of prefolding the peptide, coordinating the delivery of both agents to bacterial surfaces, recruiting the peptide to the pathogenic membranes, and supporting membrane disruption by the peptide. Given that SLs are ubiquitously and safely used in consumer products, the SL/peptide formulation engineered and mechanistically characterized in this study could represent fertile ground to develop novel synergistic agents against drug-resistant bacteria.
Collapse
Affiliation(s)
- Fei Liu
- Department
of Chemistry, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Alexander I. Greenwood
- Department
of Applied Science, William & Mary, Williamsburg, Virginia 23185, United States
| | - Yawei Xiong
- Department
of Applied Science, William & Mary, Williamsburg, Virginia 23185, United States
| | - Rebecca T. Miceli
- Department
of Chemistry, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
- Center
for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Riqiang Fu
- Center
of Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, Tallahassee, Florida 32310, United States
| | - Kyle W. Anderson
- National
Institute of Standards and Technology, Rockville, Maryland 20850, United States
| | - Scott A. McCallum
- Center
for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Mihaela Mihailescu
- Institute
for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland 20850, United States
| | - Richard Gross
- Department
of Chemistry, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
- Center
for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Myriam L. Cotten
- Department
of Applied Science, William & Mary, Williamsburg, Virginia 23185, United States
| |
Collapse
|
2
|
Caritá AC, Cavalcanti RRM, Oliveira MSS, Riske KA. Solubilization of biomimetic lipid mixtures by some commonly used non-ionic detergents. Chem Phys Lipids 2023; 255:105327. [PMID: 37442532 DOI: 10.1016/j.chemphyslip.2023.105327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 07/03/2023] [Accepted: 07/05/2023] [Indexed: 07/15/2023]
Abstract
Detergents are amphiphilic molecules often used to solubilize biological membranes and separate their components. Here we investigate the solubilization of lipid vesicles by the commonly used non-ionic detergents polyoxyethylene (20) oleyl ether (Brij 98), n-octyl-β-D-glucoside (OG), and n-dodecyl β-D maltoside (DDM) and compare the results with the standard detergent Triton X-100 (TX-100). The vesicles were composed of palmitoyl oleoyl phosphatidylcholine (POPC) or of a biomimetic ternary mixture of POPC, egg sphingomyelin (SM) and cholesterol (2:1:2 molar ratio). To follow the solubilization profile of large unilamellar vesicles (LUVs), 90° light scattering measurements were done along the titration of LUVs with the detergents. Then, giant unilamellar vesicles (GUVs) were observed with optical microscopy during exposure to the detergents, to allow direct visualization of the solubilization process. Isothermal titration calorimetry (ITC) was used to assess the binding constant of the detergents in POPC bilayers. The results show that the incorporation of TX-100, Brij 98 and, to a lesser extent, OG in the pure POPC liposomes leads to an increase in the vesicle area, which indicates their ability to redistribute between the two leaflets of the membrane in a short scale of time. On the other hand, DDM incorporates mainly in the external leaflet causing an increase in vesicle curvature/tension leading ultimately to vesicle burst. Only TX-100 and OG were able to completely solubilize the POPC vesicles, whereas the biomimetic ternary mixture was partially insoluble in all detergents tested. TX-100 and OG were able to incorporate in the bilayer of the ternary mixture and induce macroscopic phase separation of liquid-ordered (Lo) and liquid-disordered (Ld) domains, with selective solubilization of the latter. Combination of ITC data with turbidity results showed that TX-100 and OG can be incorporated up to almost 0.3 detergent/lipid, significantly more than Brij 98 and DDM. This fact seems to be directly related to their higher capacity to solubilize POPC membranes and their ability to induce macroscopic phase separation in the biomimetic lipid mixture.
Collapse
Affiliation(s)
- Amanda C Caritá
- Universidade Federal de São Paulo, Department of Biophysics, São Paulo, Brazil
| | | | | | - Karin A Riske
- Universidade Federal de São Paulo, Department of Biophysics, São Paulo, Brazil.
| |
Collapse
|
3
|
Ipsen JØ, Sørensen DM. ATP hydrolytic activity of purified Spf1p correlate with micellar lipid fluidity and is dependent on conserved residues in transmembrane helix M1. PLoS One 2022; 17:e0274908. [PMID: 36264897 PMCID: PMC9584430 DOI: 10.1371/journal.pone.0274908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 09/06/2022] [Indexed: 11/29/2022] Open
Abstract
P5A ATPases are expressed in the endoplasmic reticulum (ER) of all eukaryotic cells, and their disruption results in pleiotropic phenotypes related to severe ER stress. They were recently proposed to function in peptide translocation although their specificity have yet to be confirmed in reconstituted assays using the purified enzyme. A general theme for P-type ATPases is that binding and transport of substrates is coupled to hydrolysis of ATP in a conserved allosteric mechanism, however several independent reports have shown purified Spf1p to display intrinsic spontaneous ATP hydrolytic activity after purification. It has never been determined to what extend this spontaneous activity is caused by uncoupling of the enzyme. In this work we have purified a functional tagged version of the Saccharomyces cerevisiae P5A ATPase Spf1p and have observed that the intrinsic ATP hydrolytic activity of the purified and re-lipidated protein can be stimulated by specific detergents (C12E8, C12E10 and Tween20) in mixed lipid/detergent micelles in the absence of any apparent substrate. We further show that this increase in activity correlate with the reaction temperature and the anisotropic state of the mixed lipid/detergent micelles and further that this correlation relies on three highly conserved phenylalanine residues in M1. This suggests that at least part of the intrinsic ATP hydrolytic activity is allosterically coupled to movements in the TM domain in the purified preparations. It is suggested that free movement of the M1 helix represent an energetic constraint on catalysis and that this constraint likely is lost in the purified preparations resulting in protein with intrinsic spontaneous ATP hydrolytic activity. Removal of the N-terminal part of the protein apparently removes this activity.
Collapse
Affiliation(s)
- Johan Ørskov Ipsen
- Center for Membrane Pumps in Cells and Disease—PUMPKIN, Danish National Research Foundation, Copenhagen, Denmark
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark
- Department of Geoscience and Natural Resource Management, University of Copenhagen, Frederiksberg C, Denmark
| | - Danny Mollerup Sørensen
- Center for Membrane Pumps in Cells and Disease—PUMPKIN, Danish National Research Foundation, Copenhagen, Denmark
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark
- * E-mail:
| |
Collapse
|
4
|
Mechanisms underlying drug-mediated regulation of membrane protein function. Proc Natl Acad Sci U S A 2021; 118:2113229118. [PMID: 34753824 DOI: 10.1073/pnas.2113229118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/20/2021] [Indexed: 11/18/2022] Open
Abstract
The hydrophobic coupling between membrane proteins and their host lipid bilayer provides a mechanism by which bilayer-modifying drugs may alter protein function. Drug regulation of membrane protein function thus may be mediated by both direct interactions with the protein and drug-induced alterations of bilayer properties, in which the latter will alter the energetics of protein conformational changes. To tease apart these mechanisms, we examine how the prototypical, proton-gated bacterial potassium channel KcsA is regulated by bilayer-modifying drugs using a fluorescence-based approach to quantify changes in both KcsA function and lipid bilayer properties (using gramicidin channels as probes). All tested drugs inhibited KcsA activity, and the changes in the different gating steps varied with bilayer thickness, suggesting a coupling to the bilayer. Examining the correlations between changes in KcsA gating steps and bilayer properties reveals that drug-induced regulation of membrane protein function indeed involves bilayer-mediated mechanisms. Both direct, either specific or nonspecific, binding and bilayer-mediated mechanisms therefore are likely to be important whenever there is overlap between the concentration ranges at which a drug alters membrane protein function and bilayer properties. Because changes in bilayer properties will impact many diverse membrane proteins, they may cause indiscriminate changes in protein function.
Collapse
|
5
|
Naßwetter LC, Fischer M, Scheidt HA, Heerklotz H. Membrane-water partitioning - Tackling the challenges of poorly soluble drugs using chaotropic co-solvents. Biophys Chem 2021; 277:106654. [PMID: 34265547 DOI: 10.1016/j.bpc.2021.106654] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 06/22/2021] [Accepted: 06/24/2021] [Indexed: 12/01/2022]
Abstract
Many newly developed drugs suffer from poor water solubility and low bioavailability and hence, need special formulation vehicles like vesicular or micellar drug delivery systems. The knowledge of their membrane-water partition coefficient K becomes critical as is governs drug loading and release from the vehicle, as well as absorption into the body. The dilemma is that measuring K is particularly challenging for these very compounds. Here we establish a strategy to resolve this problem. We added DMSO to shift K and solubility into a convenient range and extrapolated these results back to zero-DMSO. Isothermal titration calorimetry revealed that logK of the kinase inhibitor Lapatinib decreased proportionally to DMSO content (2.5 - 20v%) with a slope of -1/20v% (m value = 28 kJ/mol). This implies a K of 84 mM-1 in DMSO-free buffer. This strategy should be transferable to other poorly soluble drugs and further detection methods.
Collapse
Affiliation(s)
- Leonie C Naßwetter
- Institute of Pharmaceutical Sciences, Albert-Ludwigs-Universität, Hermann-Herder-Straße 9, 79104 Freiburg, Germany.
| | - Markus Fischer
- Institute for Medical Physics and Biophysics, Leipzig University, Härtelstr. 16-18, 04107 Leipzig, Germany.
| | - Holger A Scheidt
- Institute for Medical Physics and Biophysics, Leipzig University, Härtelstr. 16-18, 04107 Leipzig, Germany.
| | - Heiko Heerklotz
- Institute of Pharmaceutical Sciences, Albert-Ludwigs-Universität, Hermann-Herder-Straße 9, 79104 Freiburg, Germany; Signalling Research Centres BIOSS and CIBSS, Albert-Ludwigs-Universität, Schänzlestraße 18, 79104 Freiburg; Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College St, Toronto ON, M5S 3M2, Canada.
| |
Collapse
|
6
|
Dietel L, Kalie L, Heerklotz H. Lipid Scrambling Induced by Membrane-Active Substances. Biophys J 2020; 119:767-779. [PMID: 32738218 DOI: 10.1016/j.bpj.2020.07.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 07/03/2020] [Accepted: 07/07/2020] [Indexed: 11/26/2022] Open
Abstract
The functional roles of the lipid asymmetry of biomembranes are attracting increasing attention. This study characterizes the activity of surfactants to induce transmembrane flip-flop of lipids and thus "scramble" this asymmetry. Detergent-induced lipid scrambling of liposomes mimicking the charge asymmetry of bacterial membranes with 20 mol % of 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-rac-glycerol in the outer leaflet only was quantified by ζ-potential measurements for octaethylene glycol dodecyl ether (C12EO8), octyl glucoside (OG), and dodecyl maltoside. Membrane leakage was separately measured by the fluorescence lifetime-based calcein leakage assay and the onset of the membrane-to-micelle transition by isothermal titration calorimetry. Partition coefficients and partial molar areas were obtained as well. For the quickly membrane-permeant C12EO8 and OG, leakage proceeds at a rather sharp threshold content in the membrane, which is well below the onset of solubilization and little dependent on incubation time; it is accompanied by fast lipid scrambling. However, unlike leakage, flip-flop is a relaxation process that speeds up gradually from taking weeks in the detergent-free membrane to minutes or less in the leaking membrane. Hence, after 24 h of incubation, 10 mol % of C12EO8 or 50 mol % of OG in the membrane suffice for virtually complete lipid scrambling, whereas leakage remains below 10% for up to 14 mol % of C12EO8 and 88 mol % of OG. There is thus a concentration window in which lipid scrambling proceeds without leakage. This implies that lipid scrambling must be considered a possible mode of action of antimicrobial peptides and other membrane-active drugs or biomolecules. A related, detergent-based protocol for scrambling the lipid asymmetry of liposomes and maybe cells without compromising their overall integrity would be a very valuable tool to study functions of lipid asymmetry.
Collapse
Affiliation(s)
- Lisa Dietel
- Institute of Pharmaceutical Sciences, University of Freiburg, Freiburg, Germany.
| | - Louma Kalie
- Institute of Pharmaceutical Sciences, University of Freiburg, Freiburg, Germany
| | - Heiko Heerklotz
- Institute of Pharmaceutical Sciences, University of Freiburg, Freiburg, Germany; Signaling Research Centers BIOSS and CIBSS, University of Freiburg, Freiburg, Germany; Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada.
| |
Collapse
|
7
|
Kaulpiboon J, Rudeekulthamrong P. Biosynthesis of methyl glucoside and its antibacterial activity against Staphylococcus aureus and Escherichia coli. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.bcdf.2019.100197] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
8
|
Ogren JI, Tong AL, Gordon SC, Chenu A, Lu Y, Blankenship RE, Cao J, Schlau-Cohen GS. Impact of the lipid bilayer on energy transfer kinetics in the photosynthetic protein LH2. Chem Sci 2018; 9:3095-3104. [PMID: 29732092 PMCID: PMC5914429 DOI: 10.1039/c7sc04814a] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 02/05/2018] [Indexed: 01/28/2023] Open
Abstract
Photosynthetic purple bacteria convert solar energy to chemical energy with near unity quantum efficiency. The light-harvesting process begins with absorption of solar energy by an antenna protein called Light-Harvesting Complex 2 (LH2). Energy is subsequently transferred within LH2 and then through a network of additional light-harvesting proteins to a central location, termed the reaction center, where charge separation occurs. The energy transfer dynamics of LH2 are highly sensitive to intermolecular distances and relative organizations. As a result, minor structural perturbations can cause significant changes in these dynamics. Previous experiments have primarily been performed in two ways. One uses non-native samples where LH2 is solubilized in detergent, which can alter protein structure. The other uses complex membranes that contain multiple proteins within a large lipid area, which make it difficult to identify and distinguish perturbations caused by protein-protein interactions and lipid-protein interactions. Here, we introduce the use of the biochemical platform of model membrane discs to study the energy transfer dynamics of photosynthetic light-harvesting complexes in a near-native environment. We incorporate a single LH2 from Rhodobacter sphaeroides into membrane discs that provide a spectroscopically amenable sample in an environment more physiological than detergent but less complex than traditional membranes. This provides a simplified system to understand an individual protein and how the lipid-protein interaction affects energy transfer dynamics. We compare the energy transfer rates of detergent-solubilized LH2 with those of LH2 in membrane discs using transient absorption spectroscopy and transient absorption anisotropy. For one key energy transfer step in LH2, we observe a 30% enhancement of the rate for LH2 in membrane discs compared to that in detergent. Based on experimental results and theoretical modeling, we attribute this difference to tilting of the peripheral bacteriochlorophyll in the B800 band. These results highlight the importance of well-defined systems with near-native membrane conditions for physiologically-relevant measurements.
Collapse
Affiliation(s)
- John I Ogren
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , MA 02139 , USA .
| | - Ashley L Tong
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , MA 02139 , USA .
| | - Samuel C Gordon
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , MA 02139 , USA .
| | - Aurélia Chenu
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , MA 02139 , USA .
| | - Yue Lu
- Department of Biology and Chemistry , Washington University in St. Louis , St. Louis , MO 63130 , USA
| | - Robert E Blankenship
- Department of Biology and Chemistry , Washington University in St. Louis , St. Louis , MO 63130 , USA
| | - Jianshu Cao
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , MA 02139 , USA .
| | - Gabriela S Schlau-Cohen
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , MA 02139 , USA .
| |
Collapse
|
9
|
Xu Y, Kuhlmann J, Brennich M, Komorowski K, Jahn R, Steinem C, Salditt T. Reconstitution of SNARE proteins into solid-supported lipid bilayer stacks and X-ray structure analysis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:566-578. [PMID: 29106973 DOI: 10.1016/j.bbamem.2017.10.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 10/01/2017] [Accepted: 10/24/2017] [Indexed: 11/26/2022]
Abstract
SNAREs are known as an important family of proteins mediating vesicle fusion. For various biophysical studies, they have been reconstituted into supported single bilayers via proteoliposome adsorption and rupture. In this study we extended this method to the reconstitution of SNAREs into supported multilamellar lipid membranes, i.e. oriented multibilayer stacks, as an ideal model system for X-ray structure analysis (X-ray reflectivity and diffraction). The reconstitution was implemented through a pathway of proteomicelle, proteoliposome and multibilayer. To monitor the structural evolution in each step, we used small-angle X-ray scattering for the proteomicelles and proteoliposomes, followed by X-ray reflectivity and grazing-incidence small-angle scattering for the multibilayers. Results show that SNAREs can be successfully reconstituted into supported multibilayers, with high enough orientational alignment for the application of surface sensitive X-ray characterizations. Based on this protocol, we then investigated the effect of SNAREs on the structure and phase diagram of the lipid membranes. Beyond this application, this reconstitution protocol could also be useful for X-ray analysis of many further membrane proteins.
Collapse
Affiliation(s)
- Yihui Xu
- Institut für Röntgenphysik, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Jan Kuhlmann
- Institut für Organische und Biomolekulare Chemie, Universität Göttingen, Tammannstraße 2, Göttingen 37077, Germany
| | - Martha Brennich
- Structural Biology Group, European Synchrotron Radiation Facility, 71 Avenue des Martyrs, CS 90181, Grenoble 38042, France
| | - Karlo Komorowski
- Institut für Röntgenphysik, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Reinhard Jahn
- Department of Neurobiology, Max-Planck Institute for Biophysical Chemistry, Am Faßberg 11, Göttingen 37077, Germany
| | - Claudia Steinem
- Institut für Organische und Biomolekulare Chemie, Universität Göttingen, Tammannstraße 2, Göttingen 37077, Germany
| | - Tim Salditt
- Institut für Röntgenphysik, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany.
| |
Collapse
|
10
|
Das S, Xu W, Lehmler HJ, Miller AF, Knutson BL, Rankin SE. Inverted Micelle-in-Micelle Configuration in Cationic/Carbohydrate Surfactant Mixtures. Chemphyschem 2017; 18:79-86. [PMID: 27788284 DOI: 10.1002/cphc.201600908] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Indexed: 11/12/2022]
Abstract
Nuclear magnetic resonance is applied to investigate the relative positions and interactions between cationic and non-ionic carbohydrate-based surfactants in mixed micelles with D2 O as the solvent. This is accomplished by using relaxation measurements [spin-lattice (T1 ) and spin-spin (T2 ) analysis] and nuclear Overhauser effect spectroscopy (NOESY). This study focuses on the interactions of n-octyl β-d-glucopyranoside (C8G1) and β-d-xylopyranoside (C8X1) with the cationic surfactant hexadecyltrimethylammonium bromide (C16 TAB). Whereas the interactions between carbohydrate and cationic surfactants are thermodynamically favorable, the NOESY results suggest that both of the sugar head groups are located preferentially at the interior core of the mixed micelles, so that they are not directly exposed to the bulk solution. The more hydrophilic sugar headgroups of C8G1 have more mobility than sugar heads of C8X1 owing to increased hydration. Herein, an inverted carbohydrate configuration in mixed micelles is proposed for the first time and supported by fluorescence spectroscopy experiments. This inverted carbohydrate headgroup configuration would limit the use of these mixed surfactants when access to the carbohydrate headgroup is important, but may present new opportunities where the carbohydrate-rich core of the micelles can be exploited.
Collapse
Affiliation(s)
- Saikat Das
- Chemical and Materials Engineering Department, University of Kentucky, Lexington, KY, 40506-0046, USA
| | - Wenjin Xu
- Department of Environmental and Occupational Health, University of Iowa, Iowa City, IA, 52242, USA
| | - Hans-Joachim Lehmler
- Department of Environmental and Occupational Health, University of Iowa, Iowa City, IA, 52242, USA
| | - Anne-Frances Miller
- Department of Chemistry, University of Kentucky, Lexington, KY, 40506-0055, USA
| | - Barbara L Knutson
- Chemical and Materials Engineering Department, University of Kentucky, Lexington, KY, 40506-0046, USA
| | - Stephen E Rankin
- Chemical and Materials Engineering Department, University of Kentucky, Lexington, KY, 40506-0046, USA
| |
Collapse
|
11
|
Fan HY, Das D, Heerklotz H. "Staying Out" Rather than "Cracking In": Asymmetric Membrane Insertion of 12:0 Lysophosphocholine. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:11655-11663. [PMID: 27715063 DOI: 10.1021/acs.langmuir.6b03292] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Interactions between detergents and model membranes are well described by the three-stage model: saturation and solubilization boundaries divide bilayer-only, bilayer-micelle coexistence, and micelle-only ranges. An underlying assumption of the model is the equilibration of detergent between the two membrane leaflets. However, many detergents partition asymmetrically at room temperature due to slow flip-flop, such as sodium dodecyl sulfate (SDS) and lysolipids. In this work, we use isothermal titration calorimetry (ITC) and dynamic light scattering (DLS) to investigate the solubilization of unilamellar POPC vesicles by 12:0 lysophosphocholine (12:0 LPC). Flip-flop of 12:0 LPC occurs beyond the time scale of our experiments, which establish a characteristic nonequilibrated state with asymmetric distribution: 12:0 LPC partitions primarily into the outer leaflet. Increasing asymmetry stress in the membrane does not lead to membrane failure, i.e., "cracking in" as seen for alkyl maltosides and other surfactants; instead, it reduces further membrane insertion which leads to the "staying out" of 12:0 LPC in solution. At above the critical micellar concentration of 12:0 LPC in the presence of the membrane, micelles persist and accommodate further LPC but take up lipid from vesicles only very slowly. Ultimately, solubilization proceeds via the micellar mechanism (Kragh-Hansen et al., 1995). With a combination of demicellization and solubilization experiments, we quantify the molar ratio partition coefficient (0.6 ± 0.1 mM-1) and enthalpy of partitioning (6.1 ± 0.3 kJ·mol-1) and estimate the maximum detergent/lipid ratio reached in the outer leaflet (<0.13). Despite the inapplicability of the three-stage model to 12:0 LPC at room temperature, we are able to extract quantitative information from ITC solubilization experiments and DLS that are important for the understanding of asymmetry-dependent processes such as endocytosis and the gating of mechanosensitive channels in vitro.
Collapse
Affiliation(s)
- Helen Y Fan
- Leslie Dan Faculty of Pharmacy, University of Toronto , Toronto, Ontario, Canada
| | - Dew Das
- Leslie Dan Faculty of Pharmacy, University of Toronto , Toronto, Ontario, Canada
| | - Heiko Heerklotz
- Leslie Dan Faculty of Pharmacy, University of Toronto , Toronto, Ontario, Canada
- Institute for Pharmaceutical Sciences, University of Freiburg , Freiburg, Germany
- BIOSS Centre for Biological Signalling Studies , Freiburg, Germany
| |
Collapse
|
12
|
Batchu KC, Hänninen S, Jha SK, Jeltsch M, Somerharju P. Factors regulating the substrate specificity of cytosolic phospholipase A 2 -alpha in vitro. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1597-1604. [DOI: 10.1016/j.bbalip.2016.06.022] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 06/28/2016] [Accepted: 06/30/2016] [Indexed: 10/21/2022]
|
13
|
Fiedler S, Heerklotz H. Vesicle Leakage Reflects the Target Selectivity of Antimicrobial Lipopeptides from Bacillus subtilis. Biophys J 2016; 109:2079-89. [PMID: 26588567 DOI: 10.1016/j.bpj.2015.09.021] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 09/17/2015] [Accepted: 09/21/2015] [Indexed: 11/30/2022] Open
Abstract
Cyclic lipopeptides act against a variety of plant pathogens and are thus highly efficient crop-protection agents. Some pesticides contain Bacillus subtilis strains that produce lipopeptide families, such as surfactins (SF), iturins (IT), and fengycins (FE). The antimicrobial activity of these peptides is mainly mediated by permeabilizing cellular membranes. We used a fluorescence-lifetime based leakage assay to examine the effect of individual lipid components in model membranes on lipopeptide activity. Leakage induction by FE was strongly inhibited by cholesterol (CHOL) as well as by phosphatidylethanolamine (PE) and -glycerol (PG) lipids. Already moderate amounts of CHOL increased the tolerable FE content in membranes by an order of magnitude to 0.5 FE per PC + CHOL. This indicates reduced FE-lipid demixing and aggregation, which is known to be required for membrane permeabilization and explains the strong inhibition by CHOL. Ergosterol (ERG) had a weak antagonistic effect. This confirms results of microbiological tests and agrees with the fungicidal activity and selectivity of FE. SF is known to be much less selective in its antimicrobial action. In line with this, liposome leakage by SF was little affected by sterols and PE. Interestingly, PG increased SF activity and changed its leakage mechanism toward all-or-none, suggesting more specific, larger, and/or longer-lived defect structures. This may be because of the reduced energetic cost of locally accumulating anionic SF in an anionic lipid matrix. IT was found largely inactive in our assays. B. subtilis QST713 produces the lipopeptides in a ratio of 6 mol SF: 37 mol FE: 57 mol IT. Leakage induced by this native mixture was inhibited by CHOL and PE, but unaffected by ERG and by PG in the absence of PE. Note that fungi contain anionic lipids, but little PE. Hence, our data explain the strong, fungicidal activity and selectivity of B. subtilis QST713 lipopeptides.
Collapse
Affiliation(s)
- Sebastian Fiedler
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada.
| | - Heiko Heerklotz
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada; Institute for Pharmaceutical Sciences, University of Freiburg, Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, Freiburg, Germany.
| |
Collapse
|
14
|
Charoensapyanan R, Ito K, Rudeekulthamrong P, Kaulpiboon J. Enzymatic synthesis of propyl-α-glycosides and their application as emulsifying and antibacterial agents. BIOTECHNOL BIOPROC E 2016. [DOI: 10.1007/s12257-016-0013-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
15
|
Agmo Hernández V, Eriksson EK, Edwards K. Ubiquinone-10 alters mechanical properties and increases stability of phospholipid membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:2233-43. [DOI: 10.1016/j.bbamem.2015.05.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Revised: 05/04/2015] [Accepted: 05/05/2015] [Indexed: 10/23/2022]
|
16
|
Batchu KC, Hokynar K, Jeltsch M, Mattonet K, Somerharju P. Substrate efflux propensity is the key determinant of Ca2+-independent phospholipase A-β (iPLAβ)-mediated glycerophospholipid hydrolysis. J Biol Chem 2015; 290:10093-103. [PMID: 25713085 DOI: 10.1074/jbc.m115.642835] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Indexed: 12/13/2022] Open
Abstract
The A-type phospholipases (PLAs) are key players in glycerophospholipid (GPL) homeostasis and in mammalian cells; Ca(2+)-independent PLA-β (iPLAβ) in particular has been implicated in this essential process. However, the regulation of this enzyme, which is necessary to avoid futile competition between synthesis and degradation, is not understood. Recently, we provided evidence that the efflux of the substrate molecules from the bilayer is the rate-limiting step in the hydrolysis of GPLs by some secretory (nonhomeostatic) PLAs. To study whether this is the case with iPLAβ as well, a mass spectrometric assay was employed to determine the rate of hydrolysis of multiple saturated and unsaturated GPL species in parallel using micelles or vesicle bilayers as the macrosubstrate. With micelles, the hydrolysis decreased with increasing acyl chain length independent of unsaturation, and modest discrimination between acyl positional isomers was observed, presumably due to the differences in the structure of the sn-1 and sn-2 acyl-binding sites of the protein. In striking contrast, no significant discrimination between positional isomers was observed with bilayers, and the rate of hydrolysis decreased with the acyl chain length logarithmically and far more than with micelles. These data provide compelling evidence that efflux of the substrate molecule from the bilayer, which also decreases monotonously with acyl chain length, is the rate-determining step in iPLAβ-mediated hydrolysis of GPLs in membranes. This finding is intriguing as it may help to understand how homeostatic PLAs are regulated and how degradation and biosynthesis are coordinated.
Collapse
Affiliation(s)
| | - Kati Hokynar
- From the Departments of Biochemistry and Developmental Biology and
| | - Michael Jeltsch
- Biomedicine, Faculty of Medicine, University of Helsinki, Helsinki 00014, Finland
| | - Kenny Mattonet
- Biomedicine, Faculty of Medicine, University of Helsinki, Helsinki 00014, Finland
| | | |
Collapse
|
17
|
Schmid S, Marion Schneider E, Brier E, Bäuerle P. Self-organizing carbohydrate-oligothiophene-hybrids for eukaryotic membrane-labelling. J Mater Chem B 2014; 2:7861-7865. [DOI: 10.1039/c4tb01472c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Self-assembling d-(+) and l-(−) mannose-functionalized oligothiophene hybrids were synthesized via Sonogashira cross-coupling reaction. The hybrids are taken up into live myeloid cells and offer an ideal platform for imaging of artificial and cellular membranes.
Collapse
Affiliation(s)
- Sylvia Schmid
- Institute of Organic Chemistry II and Advanced Materials
- University of Ulm
- 89081 Ulm, Germany
| | | | - Eduard Brier
- Institute of Organic Chemistry II and Advanced Materials
- University of Ulm
- 89081 Ulm, Germany
| | - Peter Bäuerle
- Institute of Organic Chemistry II and Advanced Materials
- University of Ulm
- 89081 Ulm, Germany
| |
Collapse
|
18
|
Muzzalupo R, Tavano L, La Mesa C. Alkyl glucopyranoside-based niosomes containing methotrexate for pharmaceutical applications: Evaluation of physico-chemical and biological properties. Int J Pharm 2013; 458:224-9. [DOI: 10.1016/j.ijpharm.2013.09.011] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 09/10/2013] [Accepted: 09/15/2013] [Indexed: 10/26/2022]
|
19
|
Bilayer Composition, Temperature, Speciation Effects and the Role of Bilayer Chain Ordering on Partitioning of Dexamethasone and its 21-Phosphate. Pharm Res 2013; 30:3154-69. [DOI: 10.1007/s11095-013-1143-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 07/01/2013] [Indexed: 10/26/2022]
|
20
|
Misran O, Timimi BA, Heidelberg T, Sugimura A, Hashim R. Deuterium NMR Investigation of the lyotropic phases of alkyl β-glycoside/D2O systems. J Phys Chem B 2013; 117:7335-44. [PMID: 23718628 DOI: 10.1021/jp401787b] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
We have investigated the phase behavior of four glycosides (βC8OGlc, βC8SGlc, βC10OGlc, βC8OGal) in water and D2O by optical polarizing microscopy and deuterium NMR. Previously published phase diagrams were evaluated by deuterium NMR, via monitoring D2O spectra, and confirmed the presence of the hexagonal, bicontinuous cubic, and lamellar phases in these glycosides. We have also shown the presence of the gel phase in (βC10OGlc) and observed the extensive supercooling of the lamellar phase to temperatures well below the Kraft line. While the main features of the phase diagrams were confirmed, some phase boundaries were found to be slightly different. Magnetically aligned spectra were also observed for relatively dilute samples for the hexagonal phase (βC8OGlc and βC8OGal) and the lamellar phase (βC8SGlc and βC10OGlc). The average number of bound water molecules per headgroup in the lamellar phase for the glycosides was determined by the systematic measurement of the quadrupolar splitting of D2O over a wide range of values of the (glycoside/water) molar ratio. The number of water molecules bound to the headgroup was found on average to be about 1.6-1.7 water molecules with no significant differences in this value for the different glycosides (and over the temperature range investigated), indicating that the bound water content is predominately influenced by the number of hydroxyl groups of the headgroup only. However, this bound water content of only 1.6-1.7 water molecules per sugar headgroup is surprisingly low, suggesting strong intermolecular interactions of the OH groups of headgroup sugars. The results are in line with computational results reported earlier for the octyl-β-glucoside and β-galactoside, which show the presence of strong intralayer hydrogen bonding.
Collapse
Affiliation(s)
- Omar Misran
- Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | | | | | | | | |
Collapse
|
21
|
Structure, thermodynamics and dynamics of the isotropic phase of spherical non-ionic surfactant micelles. J Colloid Interface Sci 2013. [PMID: 23201065 DOI: 10.1016/j.jcis.2012.10.039] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We investigate a non-ionic surfactant (C(12)E(8))/water binary mixture, over a wide range of concentrations and temperatures (i.e. 1-35 wt.% of C(12)E(8) and 10-60 °C in temperature) by means of different experimental techniques: Small-Angle Neutron Scattering (SANS), Quasi Elastic Light Scattering (QELS) and High Frequency Rheology. The aims of this work are to provide information on structure, thermodynamics and dynamics of the isotropic phase of such a micellar system and, by combining these different types of information, to obtain a comprehensive image of the behaviour of this phase. Our results demonstrate that structural, thermodynamic and dynamic properties of these solutions are fully monitored by the temperature-induced changes in the ethylene-glycol chain hydration. They confirm that C(12)E(8) micelles are spherical and do not grow in the investigated range of concentrations and temperatures. They demonstrate that the interaction potential between C(12)E(8) micelles is more complicated than what was previously described, with an additional repulsive interaction. They allow us to put forward explanations for the Isotropic-Ordered phase transition as well as for the temperature behaviour of the viscosity of C(12)E(8) micellar solutions. Our investigation provides new and valuable information on the dynamics of these mixtures that reflect the complexity of the interaction potential between the C(12)E(8) micelles. It shows that concentrated solutions exhibit a viscoelastic behaviour that can be described by a simple Maxwell model.
Collapse
|
22
|
Li-Blatter X, Beck A, Seelig A. P-glycoprotein-ATPase modulation: the molecular mechanisms. Biophys J 2012; 102:1383-93. [PMID: 22455921 DOI: 10.1016/j.bpj.2012.02.018] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 01/10/2012] [Accepted: 02/07/2012] [Indexed: 10/28/2022] Open
Abstract
P-glycoprotein-ATPase is an efflux transporter of broad specificity that counteracts passive allocrit influx. Understanding the rate of allocrit transport therefore matters. Generally, the rates of allocrit transport and ATP hydrolysis decrease exponentially with increasing allocrit affinity to the transporter. Here we report unexpectedly strong down-modulation of the P-glycoprotein-ATPase by certain detergents. To elucidate the underlying mechanism, we chose 34 electrically neutral and cationic detergents with different hydrophobic and hydrophilic characteristics. Measurement of the P-glycoprotein-ATPase activity as a function of concentration showed that seven detergents activated the ATPase as expected, whereas 27 closely related detergents reduced it significantly. Assessment of the free energy of detergent partitioning into the lipid membrane and the free energy of detergent binding from the membrane to the transporter revealed that the ratio, q, of the two free energies of binding determined the rate of ATP hydrolysis. Neutral (cationic) detergents with a ratio of q = 2.7 ± 0.2 (q > 3) followed the aforementioned exponential dependence. Small deviations from the optimal ratio strongly reduced the rates of ATP hydrolysis and flopping, respectively, whereas larger deviations led to an absence of interaction with the transporter. P-glycoprotein-ATPase inhibition due to membrane disordering by detergents could be fully excluded using (2)H-NMR-spectroscopy. Similar principles apply to modulating drugs.
Collapse
|
23
|
Nazari M, Kurdi M, Heerklotz H. Classifying surfactants with respect to their effect on lipid membrane order. Biophys J 2012; 102:498-506. [PMID: 22325272 DOI: 10.1016/j.bpj.2011.12.029] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Revised: 10/04/2011] [Accepted: 12/09/2011] [Indexed: 11/19/2022] Open
Abstract
We propose classifying surfactants with respect to their effect on membrane order, which is derived from the time-resolved fluorescence anisotropy of DPH. This may help in understanding why certain surfactants, including biosurfactants such as antimicrobial lipopeptides and saponins, often show a superior performance to permeabilize and lyse membranes and/or a better suitability for membrane protein solubilization. Micelle-forming surfactants induce curvature stress in membranes that causes disordering and, finally, lysis. Typical detergents such as C(12)EO(8), octyl glucoside, SDS, and lauryl maltoside initiate membrane lysis after reaching a substantial, apparently critical extent of disordering. In contrast, the fungicidal lipopeptides surfactin, fengycin, and iturin from Bacillus subtilis QST713 as well as digitonin, CHAPS, and lysophosphatidylcholine solubilize membranes without substantial, overall disordering. We hypothesize they disrupt the membrane locally due to a spontaneous segregation from the lipid and/or packing defects and refer to them as heterogeneously perturbing. This may account for enhanced activity, selectivity, and mutual synergism of antimicrobial biosurfactants and reduced destabilization of membrane proteins by CHAPS or digitonin. Triton shows the pattern of a segregating surfactant in the presence of cholesterol.
Collapse
Affiliation(s)
- Mozhgan Nazari
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | | | | |
Collapse
|
24
|
Rusinova R, Herold KF, Sanford RL, Greathouse DV, Hemmings HC, Andersen OS. Thiazolidinedione insulin sensitizers alter lipid bilayer properties and voltage-dependent sodium channel function: implications for drug discovery. ACTA ACUST UNITED AC 2012; 138:249-70. [PMID: 21788612 PMCID: PMC3149818 DOI: 10.1085/jgp.201010529] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
The thiazolidinediones (TZDs) are used in the treatment of diabetes mellitus type 2. Their canonical effects are mediated by activation of the peroxisome proliferator–activated receptor γ (PPARγ) transcription factor. In addition to effects mediated by gene activation, the TZDs cause acute, transcription-independent changes in various membrane transport processes, including glucose transport, and they alter the function of a diverse group of membrane proteins, including ion channels. The basis for these off-target effects is unknown, but the TZDs are hydrophobic/amphiphilic and adsorb to the bilayer–water interface, which will alter bilayer properties, meaning that the TZDs may alter membrane protein function by bilayer-mediated mechanisms. We therefore explored whether the TZDs alter lipid bilayer properties sufficiently to be sensed by bilayer-spanning proteins, using gramicidin A (gA) channels as probes. The TZDs altered bilayer elastic properties with potencies that did not correlate with their affinity for PPARγ. At concentrations where they altered gA channel function, they also altered the function of voltage-dependent sodium channels, producing a prepulse-dependent current inhibition and hyperpolarizing shift in the steady-state inactivation curve. The shifts in the inactivation curve produced by the TZDs and other amphiphiles can be superimposed by plotting them as a function of the changes in gA channel lifetimes. The TZDs’ partition coefficients into lipid bilayers were measured using isothermal titration calorimetry. The most potent bilayer modifier, troglitazone, alters bilayer properties at clinically relevant free concentrations; the least potent bilayer modifiers, pioglitazone and rosiglitazone, do not. Unlike other TZDs tested, ciglitazone behaves like a hydrophobic anion and alters the gA monomer–dimer equilibrium by more than one mechanism. Our results provide a possible mechanism for some off-target effects of an important group of drugs, and underscore the importance of exploring bilayer effects of candidate drugs early in drug development.
Collapse
Affiliation(s)
- Radda Rusinova
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY 10065, USA.
| | | | | | | | | | | |
Collapse
|
25
|
Corley SC, Sprangers P, Albert AD. The bilayer enhances rhodopsin kinetic stability in bovine rod outer segment disk membranes. Biophys J 2011; 100:2946-54. [PMID: 21689528 DOI: 10.1016/j.bpj.2011.05.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 05/04/2011] [Accepted: 05/09/2011] [Indexed: 10/18/2022] Open
Abstract
Rhodopsin is a kinetically stable protein constituting >90% of rod outer segment disk membrane protein. To investigate the bilayer contribution to rhodopsin kinetic stability, disk membranes were systematically disrupted by octyl-β-D-glucopyranoside. Rhodopsin kinetic stability was examined under subsolubilizing (rhodopsin in a bilayer environment perturbed by octyl-β-D-glucopyranoside) and under fully solubilizing conditions (rhodopsin in a micelle with cosolubilized phospholipids). As determined by DSC, rhodopsin exhibited a scan-rate-dependent irreversible endothermic transition at all stages of solubilization. The transition temperature (T(m)) decreased in the subsolubilizing stage. However, once the rhodopsin was in a micelle environment there was little change of the T(m) as the phospholipid/rhodopsin ratio in the mixed micelles decreased during the fully solubilized stage. Rhodopsin thermal denaturation is consistent with the two-state irreversible model at all stages of solubilization. The activation energy of denaturation (E(act)) was calculated from the scan rate dependence of the T(m) and from the rate of rhodopsin thermal bleaching at all stages of solubilization. The E(act) as determined by both techniques decreased in the subsolubilizing stage, but remained constant once fully solubilized. These results indicate the bilayer structure increases the E(act) to rhodopsin denaturation.
Collapse
Affiliation(s)
- Scott C Corley
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, USA
| | | | | |
Collapse
|
26
|
Lyukmanova EN, Shenkarev ZO, Khabibullina NF, Kopeina GS, Shulepko MA, Paramonov AS, Mineev KS, Tikhonov RV, Shingarova LN, Petrovskaya LE, Dolgikh DA, Arseniev AS, Kirpichnikov MP. Lipid-protein nanodiscs for cell-free production of integral membrane proteins in a soluble and folded state: comparison with detergent micelles, bicelles and liposomes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1818:349-58. [PMID: 22056981 DOI: 10.1016/j.bbamem.2011.10.020] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Revised: 10/03/2011] [Accepted: 10/18/2011] [Indexed: 11/26/2022]
Abstract
Production of integral membrane proteins (IMPs) in a folded state is a key prerequisite for their functional and structural studies. In cell-free (CF) expression systems membrane mimicking components could be added to the reaction mixture that promotes IMP production in a soluble form. Here lipid-protein nanodiscs (LPNs) of different lipid compositions (DMPC, DMPG, POPC, POPC/DOPG) have been compared with classical membrane mimicking media such as detergent micelles, lipid/detergent bicelles and liposomes by their ability to support CF synthesis of IMPs in a folded and soluble state. Three model membrane proteins of different topology were used: homodimeric transmembrane (TM) domain of human receptor tyrosine kinase ErbB3 (TM-ErbB3, 1TM); voltage-sensing domain of K(+) channel KvAP (VSD, 4TM); and bacteriorhodopsin from Exiguobacterium sibiricum (ESR, 7TM). Structural and/or functional properties of the synthesized proteins were analyzed. LPNs significantly enhanced synthesis of the IMPs in a soluble form regardless of the lipid composition. A partial disintegration of LPNs composed of unsaturated lipids was observed upon co-translational IMP incorporation. Contrary to detergents the nanodiscs resulted in the synthesis of ~80% active ESR and promoted correct folding of the TM-ErbB3. None of the tested membrane mimetics supported CF synthesis of correctly folded VSD, and the protocol of the domain refolding was developed. The use of LPNs appears to be the most promising approach to CF production of IMPs in a folded state. NMR analysis of (15)N-Ile-TM-ErbB3 co-translationally incorporated into LPNs shows the great prospects of this membrane mimetics for structural studies of IMPs produced by CF systems.
Collapse
Affiliation(s)
- E N Lyukmanova
- Russian Academy of Sciences, Moscow, Russian Federation.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Velluto D, Gasbarri C, Angelini G, Fontana A. Use of simple kinetic and reaction-order measurements for the evaluation of the mechanism of surfactant-liposome interactions. J Phys Chem B 2011; 115:8130-7. [PMID: 21604798 DOI: 10.1021/jp2026187] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Surfactant-liposome interactions have been previously studied through different methods and techniques. We present here a classical physical chemistry study on liposome solutions added to destabilizing agents at concentrations well above the solubilization concentration, which enable us to draw useful and interesting conclusions about the mechanism of surfactant-induced liposomal breakdown by simply exploiting the kinetics and the reaction order of the liposomal content release. In such excess of surfactant, the mechanism of surfactant-induced rupture of the liposomes has been demonstrated to be different from that proposed for low surfactant concentrations. Thus, depending on the surfactant concentration, two prevailing processes have been evidenced: (i) a cooperative mechanism that implies the assembly of a critical number of surfactant molecules to trigger the formation of a channel and therefore the release of the liposomal content and (ii) a mechanism driven by direct interaction of the surfactant molecules with the lipids that causes the complete solubilization of the liposomes. The former mechanism occurs at low surfactant concentrations, whereas the latter occurs at higher concentrations and above the CMC of the surfactants. The effect of different guests embedded into the liposomal bilayer on the mechanism of surfactant-induced liposomal breakdown has been compared by using the second-order rate constants measured for the liposome breakdown process.
Collapse
Affiliation(s)
- Diana Velluto
- Institute for Bioengineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | | | | | | |
Collapse
|
28
|
A SANS investigation of micelles in mixtures of cetyltrimethylammonium bromide (CTAB)/octyl-β-d-glucopyranoside (C8G1) in water/glycerol solvent. Colloids Surf A Physicochem Eng Asp 2011. [DOI: 10.1016/j.colsurfa.2010.11.071] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
29
|
Ménager C, Guemghar D, Cabuil V, Lesieur S. Interaction of n-octyl β,D-glucopyranoside with giant magnetic-fluid-loaded phosphatidylcholine vesicles: direct visualization of membrane curvature fluctuations as a function of surfactant partitioning between water and lipid bilayer. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:15453-15463. [PMID: 20825201 DOI: 10.1021/la102532h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The present study deals with the morphological modifications of giant dioleoyl phosphatidylcholine vesicles (DOPC GUVs) induced by the nonionic surfactant n-octyl β,D-glucopyranoside at sublytic levels, i.e., in the first steps of the vesicle-to-micelle transition process, when surfactant inserts into the vesicle bilayer without disruption. Experimental conditions were perfected to exactly control the surfactant bilayer composition of the vesicles, in line with former work focused on the mechanical properties of the membrane of magnetic-fluid-loaded DOPC GUVs submitted to a magnetic field. The purpose here was to systematically examine, in the absence of any external mechanical constraint, the dynamics of giant vesicle shape and membrane deformations as a function of surfactant partitioning between the aqueous phase and the lipid membrane, beforehand established by turbidity measurements from small unilamellar vesicles.
Collapse
Affiliation(s)
- Christine Ménager
- UPMC Univ Paris 06, UMR 7195 PECSA, Physicochimie des Electrolytes, Colloïdes, Sciences Analytiques, F-75005 Paris France
| | | | | | | |
Collapse
|
30
|
Meier M, Seelig J. Lipid and peptide dynamics in membranes upon insertion of n-alkyl-beta-D-glucopyranosides. Biophys J 2010; 98:1529-38. [PMID: 20409472 DOI: 10.1016/j.bpj.2009.12.4286] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2009] [Revised: 11/23/2009] [Accepted: 12/08/2009] [Indexed: 11/16/2022] Open
Abstract
The effect of nonionic detergents of the n-alkyl-beta-D-glucopyranoside class on the ordering of lipid bilayers and the dynamics of membrane-embedded peptides were investigated with 2H- and 31P-NMR. 1,2-dipalmitoyl-sn-glycero-3-phosphocholine was selectively deuterated at methylene segments C-2, C-7, and C-16 of the two fatty acyl chains. Two trans-membrane helices, WALP-19 and glycophorin A(71-98), were synthesized with Ala-d3 in the central region of the alpha-helix. n-Alkyl-beta-D-glucopyranosides with alkyl chains with 6, 7, 8, and 10 carbon atoms were added at increasing concentrations to the lipid membrane. The bilayer structure is retained up to a detergent/lipid molar ratio of 1:1. The insertion of the detergents leads to a selective disordering of the lipids. The headgroup region remains largely unaffected; the fatty acyl chain segments parallel to the detergent alkyl chain are only modestly disordered (10-20%), whereas lipid segments beyond the methyl terminus of the detergent show a decrease of up to 50%. The change in the bilayer order profile corresponds to an increase in bilayer entropy. Insertion of detergents into the lipid bilayers is completely entropy-driven. The entropy change accompanying lipid disorder is equivalent in magnitude to the hydrophobic effect. Ala-d3 deuterated WALP-19 and GlycA(71-97) were incorporated into bilayers of 1,2-dimyristoyl-sn-glycero-3-phosphocholine at a peptide/lipid molar ratio of 1:100 and measured above the 1,2-dimyristoyl-sn-glycero-3-phosphocholine gel/liquid-crystal phase transition. Well-resolved 2H-NMR quadrupole splittings were observed for the two trans-membrane helices, revealing a rapid rotation of the CD3 methyl rotor superimposed on an additional rotation of the whole peptide around the bilayer normal. The presence of detergent fluidizes the membrane and produces magnetic alignment of bilayer domains but does not produce essential changes in the peptide conformation or dynamics.
Collapse
Affiliation(s)
- Matthias Meier
- Department of Bioengineering, Stanford University, Stanford, California, USA
| | | |
Collapse
|
31
|
Haimi P, Hermansson M, Batchu KC, Virtanen JA, Somerharju P. Substrate efflux propensity plays a key role in the specificity of secretory A-type phospholipases. J Biol Chem 2010; 285:751-60. [PMID: 19887372 PMCID: PMC2804224 DOI: 10.1074/jbc.m109.061218] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Revised: 11/01/2009] [Indexed: 01/01/2023] Open
Abstract
To better understand the principles underlying the substrate specificity of A-type phospholipases (PLAs), a high throughput mass spectrometric assay was employed to study the effect of acyl chain length and unsaturation of phospholipids on their rate of hydrolysis by three different secretory PLAs in micelles and vesicle bilayers. With micelles, each enzyme responded differently to substrate acyl chain unsaturation and double bond position, probably reflecting differences in the accommodative properties of their substrate binding sites. Experiments with saturated acyl positional isomers indicated that the length of the sn2 chain was more critical than that of the sn1 chain, suggesting tighter association of the former with the enzyme. Only the first 9-10 carbons of the sn2 acyl chain seem to interact intimately with the active site. Strikingly, no discrimination between positional isomers was observed with vesicles, and the rate of hydrolysis decreased far more with increasing chain length than with micelles, suggesting that translocation of the phospholipid substrate to the active site is rate-limiting with bilayers. Supporting this conclusion, acyl chain structure affected hydrolysis and spontaneous intervesicle transfer, which correlates with lipid efflux propensity, analogously. We conclude that substrate efflux propensity plays a more important role in the specificity of secretory PLA(2)s than commonly thought and could also be a key attribute in phospholipid homeostasis in which (unknown) PLA(2)s are key players.
Collapse
Affiliation(s)
- Perttu Haimi
- From the Institute of Biomedicine, Department of Medical Biochemistry and Developmental Biology, University of Helsinki, PL 63, 00014 Helsinki, Finland
| | - Martin Hermansson
- From the Institute of Biomedicine, Department of Medical Biochemistry and Developmental Biology, University of Helsinki, PL 63, 00014 Helsinki, Finland
| | - Krishna Chaithanya Batchu
- From the Institute of Biomedicine, Department of Medical Biochemistry and Developmental Biology, University of Helsinki, PL 63, 00014 Helsinki, Finland
| | - Jorma A. Virtanen
- From the Institute of Biomedicine, Department of Medical Biochemistry and Developmental Biology, University of Helsinki, PL 63, 00014 Helsinki, Finland
| | - Pentti Somerharju
- From the Institute of Biomedicine, Department of Medical Biochemistry and Developmental Biology, University of Helsinki, PL 63, 00014 Helsinki, Finland
| |
Collapse
|
32
|
Ouazia D, Bearne SL. A continuous assay for alpha-methylacyl-coenzyme A racemase using circular dichroism. Anal Biochem 2009; 398:45-51. [PMID: 19854148 DOI: 10.1016/j.ab.2009.10.039] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2009] [Revised: 10/20/2009] [Accepted: 10/21/2009] [Indexed: 12/22/2022]
Abstract
alpha-Methylacyl-coenzyme A racemase (AMACR) catalyzes the epimerization of (2R)- and (2S)-methyl branched fatty acyl-coenzyme A (CoA) thioesters. AMACR is a biomarker for prostate cancer and a putative target for the development of therapeutic agents directed against the disease. To facilitate development of AMACR inhibitors, a continuous circular dichroism (CD)-based assay has been developed. The open reading frame encoding AMACR from Mycobacterium tuberculosis (MCR) was subcloned into a pET15b vector, and the enzyme was overexpressed and purified using metal ion affinity chromatography. The rates of MCR-catalyzed epimerization of either (2R)- or (2S)-ibuprofenoyl-CoA were determined by following the change in ellipticity at 279nm in the presence of octyl-beta-d-glucopyranoside (0.2%). MCR exhibited slightly higher affinity for (2R)-ibuprofenoyl-CoA (K(m)=48+/-5microM, k(cat)=291+/-30s(-1)), but turned over (2S)-ibuprofenoyl-CoA (K(m)=86+/-6microM, k(cat)=450+/-14s(-1)) slightly faster. MCR expressed as a fusion protein bearing an N-terminal His(6)-tag had a catalytic efficiency (k(cat)/K(m)) that was reduced 22% and 47% in the 2S-->2R and 2R-->2S directions, respectively, relative to untagged enzyme. The continuous CD-based assay offers an economical and efficient alternative method to the labor-intensive, fixed-time assays currently used to measure AMACR activity.
Collapse
Affiliation(s)
- Dahmane Ouazia
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada B3H 1X5
| | | |
Collapse
|
33
|
Abstract
Surfactants are surface-active, amphiphilic compounds that are water-soluble in the micro- to millimolar range, and self-assemble to form micelles or other aggregates above a critical concentration. This definition comprises synthetic detergents as well as amphiphilic peptides and lipopeptides, bile salts and many other compounds. This paper reviews the biophysics of the interactions of surfactants with membranes of insoluble, naturally occurring lipids. It discusses structural, thermodynamic and kinetic aspects of membrane-water partitioning, changes in membrane properties induced by surfactants, membrane solubilisation to micelles and other phases formed by lipid-surfactant systems. Each section defines and derives key parameters, mentions experimental methods for their measurement and compiles and discusses published data. Additionally, a brief overview is given of surfactant-like effects in biological systems, technical applications of surfactants that involve membrane interactions, and surfactant-based protocols to study biological membranes.
Collapse
|
34
|
Liao JH, Chen CS, Maher TJ, Liu CY, Lin MH, Wu TH, Wu SH. Astaxanthin Interacts with Selenite and Attenuates Selenite-Induced Cataractogenesis. Chem Res Toxicol 2009; 22:518-25. [DOI: 10.1021/tx800378z] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jiahn-Haur Liao
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan, Department of Pharmaceutical Sciences, Massachusetts College of Pharmacy and Health Sciences, Boston, Massachusetts 02115, USA, and School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei 110, Taiwan
| | - Chien-Sheng Chen
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan, Department of Pharmaceutical Sciences, Massachusetts College of Pharmacy and Health Sciences, Boston, Massachusetts 02115, USA, and School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei 110, Taiwan
| | - Timothy J. Maher
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan, Department of Pharmaceutical Sciences, Massachusetts College of Pharmacy and Health Sciences, Boston, Massachusetts 02115, USA, and School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei 110, Taiwan
| | - Chiung-Yueh Liu
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan, Department of Pharmaceutical Sciences, Massachusetts College of Pharmacy and Health Sciences, Boston, Massachusetts 02115, USA, and School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei 110, Taiwan
| | - Mei-Hsiang Lin
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan, Department of Pharmaceutical Sciences, Massachusetts College of Pharmacy and Health Sciences, Boston, Massachusetts 02115, USA, and School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei 110, Taiwan
| | - Tzu-Hua Wu
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan, Department of Pharmaceutical Sciences, Massachusetts College of Pharmacy and Health Sciences, Boston, Massachusetts 02115, USA, and School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei 110, Taiwan
| | - Shih-Hsiung Wu
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan, Department of Pharmaceutical Sciences, Massachusetts College of Pharmacy and Health Sciences, Boston, Massachusetts 02115, USA, and School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei 110, Taiwan
| |
Collapse
|
35
|
Lee DK, Kwon BS, Ramamoorthy A. Freezing point depression of water in phospholipid membranes: a solid-state NMR study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:13598-13604. [PMID: 18991419 PMCID: PMC2649677 DOI: 10.1021/la8023698] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Lipid-water interaction plays an important role in the properties of lipid bilayers, cryoprotectants, and membrane-associated peptides and proteins. The temperature at which water bound to lipid bilayers freezes is lower than that of free water. Here, we report a solid-state NMR investigation on the freezing point depression of water in phospholipid bilayers in the presence and absence of cholesterol. Deuterium NMR spectra at different temperatures ranging from -75 to + 10 degrees C were obtained from fully (2)H2O-hydrated POPC (1-palmitoyl-2-oleoylphosphatidylcholine) multilamellar vesicles (MLVs), prepared with and without cholesterol, to determine the freezing temperature of water and the effect of cholesterol on the freezing temperature of water in POPC bilayers. Our 2H NMR experiments reveal the motional behavior of unfrozen water molecules in POPC bilayers even at temperatures significantly below 0 degrees C and show that the presence of cholesterol further lowered the freezing temperature of water in POPC bilayers. These results suggest that in the presence of cholesterol the fluidity and dynamics of lipid bilayers can be retained even at very low temperatures as exist in the liquid crystalline phase of the lipid. Therefore, bilayer samples prepared with a cryoprotectant like cholesterol should enable the performance of multidimensional solid-state NMR experiments to investigate the structure, dynamics, and topology of membrane proteins at a very low temperature with enhanced sample stability and possibly a better sensitivity. Phosphorus-31 NMR data suggest that lipid bilayers can be aligned at low temperatures, while 15N NMR experiments demonstrate that such aligned samples can be used to enhance the signal-to-noise ratio of is 15N chemical shift spectra of a 37-residue human antimicrobial peptide, LL-37.
Collapse
Affiliation(s)
- Dong-Kuk Lee
- Department of Fine Chemistry, Seoul National University of Technology, Seoul 139-743, Korea.
| | | | | |
Collapse
|
36
|
Apel-Paz M, Doncel GF, Vanderlick TK. Surfactants as Microbicidal Contraceptives: A Calorimetric Study of Partitioning and Translocation in Model Membrane Systems. Ind Eng Chem Res 2008. [DOI: 10.1021/ie071105e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
37
|
Trépout S, Taveau JC, Mornet S, Benabdelhak H, Ducruix A, Lambert O. Organization of reconstituted lipoprotein MexA onto supported lipid membrane. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2007; 36:1029-37. [PMID: 17665187 DOI: 10.1007/s00249-007-0208-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2007] [Revised: 06/22/2007] [Accepted: 07/10/2007] [Indexed: 01/16/2023]
Abstract
MexA, a periplasmic component of OprM-MexA-MexB tripartite multidrug efflux pump from Pseudomonas aeruginosa, is natively anchored via its fatty acid in the bacteria inner membrane protruding into the periplasm. We used supported lipid bilayer (SLB) to attach the protein to a single leaflet mimicking its perisplamic orientation. For that purpose, we studied the solubilization of DOPC lipid bilayer supported on silica surface with beta-octyl glucoside (betaOG). First we showed that SLBs resist to betaOG concentrations that usually solubilize liposomes. Native form of MexA was directly inserted in the outer leaflet at (betaOG concentrations in a range of 20-25 mM). Second, observations by cryo-electron microscopy (cryoEM) revealed a dense protein layer attached to the surface corresponding to a 13-nm layer of MexA proteins. Analysis of protein densities allows proposing a schematic organization of native MexA inserted in lipid membrane. This structural organization provides further insights with respect to the partially solved structure of the soluble form.
Collapse
Affiliation(s)
- Sylvain Trépout
- Laboratoire d'Imagerie Moléculaire et Nano-Bio-Technologie, UMR 5248 CBMN, CNRS, Université Bordeaux 1, ENITAB, IECB, 2 rue Robert Escarpit, 33607, Pessac, France
| | | | | | | | | | | |
Collapse
|
38
|
Tsamaloukas AD, Keller S, Heerklotz H. Uptake and release protocol for assessing membrane binding and permeation by way of isothermal titration calorimetry. Nat Protoc 2007; 2:695-704. [PMID: 17406632 DOI: 10.1038/nprot.2007.98] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The activity of many biomolecules and drugs crucially depends on whether they bind to biological membranes and whether they translocate to the opposite lipid leaflet and trans aqueous compartment. A general strategy to measure membrane binding and permeation is the uptake and release assay, which compares two apparent equilibrium situations established either by the addition or by the extraction of the solute of interest. Only solutes that permeate the membrane sufficiently fast do not show any dependence on the history of sample preparation. This strategy can be pursued for virtually all membrane-binding solutes, using any method suitable for detecting binding. Here, we present in detail one example that is particularly well developed, namely the nonspecific membrane partitioning and flip-flop of small, nonionic solutes as characterized by isothermal titration calorimetry. A complete set of experiments, including all sample preparation procedures, can typically be accomplished within 2 days. Analogous protocols for studying charged solutes, virtually water-insoluble, hydrophobic compounds or specific ligands are also considered.
Collapse
Affiliation(s)
- Alekos D Tsamaloukas
- Department of Chemistry and Physics, University of Toronto, 80 Saint George Street, Toronto, Ontario, Canada M5S 3H6
| | | | | |
Collapse
|
39
|
Seelig A, Gerebtzoff G. Enhancement of drug absorption by noncharged detergents through membrane and P-glycoprotein binding. Expert Opin Drug Metab Toxicol 2006; 2:733-52. [PMID: 17014392 DOI: 10.1517/17425255.2.5.733] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Noncharged detergents are used as excipients in drug formulations. Until recently, they were considered as inert compounds, enhancing drug absorption essentially by improving drug solubility. However, many detergents insert into lipid membranes, although to different extents, and change the lateral packing density of membranes at high concentrations. Moreover, they bind to the efflux transporter P-glycoprotein (P-gp) and most likely to related transporters and metabolising enzymes with overlapping substrate specificities. If their affinity to P-gp is higher than that of the coadministered drug they act as modulators or inhibitors of P-gp and enhance drug absorption. Inhibition of P-gp and related proteins can, however, cause severe side effects. This paper first reviews the membrane binding propensity of different noncharged detergents (including poloxamers) and discusses their ability to bind to P-gp. Second, literature data on drug uptake enhancement by noncharged detergents, obtained in vivo and in vitro, are analysed at the molecular level. The present analysis provides the tools for an approximate and simple prior estimate of the membrane and P-gp binding ability of noncharged detergents based on a modular binding approach.
Collapse
Affiliation(s)
- Anna Seelig
- Biozentrum, Biophysical Chemistry, University of Basel, Klingelbergstrasse 70, CH-4057 Basel, Switzerland.
| | | |
Collapse
|
40
|
Tsamaloukas A, Szadkowska H, Heerklotz H. Nonideal mixing in multicomponent lipid/detergent systems. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2006; 18:S1125-S1138. [PMID: 21690833 DOI: 10.1088/0953-8984/18/28/s02] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A detailed understanding of the mixing properties of membranes to which detergents are added is mandatory for improving the application and interpretation of detergent based protein or lipid extraction assays. For Triton X-100 (TX-100), a nonionic detergent frequently used in the process of solubilizing and purifying membrane proteins and lipids, we present here a detailed study of the mixing properties of binary and ternary lipid mixtures by means of high-sensitivity isothermal titration calorimetry (ITC). To this end the partitioning thermodynamics of TX-100 molecules from the aqueous phase to lipid bilayers composed of various mixtures of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), egg-sphingomyelin (SM), and cholesterol (cho) are characterized. Composition-dependent partition coefficients K are analysed within the frame of a thermodynamic model developed to describe nonideal mixing in multicomponent lipid/detergent systems. The results imply that POPC, fluid SM, and TX-100 mix almost ideally (nonideality parameters |ρ(α/β)|<RT). However, favourable SM/cho (ρ(SM/cho)≤-6RT) and unfavourable PC/cho interactions (ρ(PC/cho) = 2RT) may under certain conditions cause POPC/TX-100-enriched domains to segregate from SM/cho-enriched ones. TX-100/cho contacts are unfavourable (ρ(cho/TX) = 4RT), so the system tends to avoid them. That means, addition of TX-100 promotes the separation of SM/cho-rich from PC/TX-100-rich domains. It appears that cho/detergent interactions are crucial governing the abundance and composition of detergent-resistant membrane patches.
Collapse
Affiliation(s)
- Alekos Tsamaloukas
- Biozentrum of the University of Basel, Division of Biophysical Chemistry, Klingelbergstrasse 70, CH-4056 Basel, Switzerland
| | | | | |
Collapse
|
41
|
Aagaard TH, Kristensen MN, Westh P. Packing properties of 1-alkanols and alkanes in a phospholipid membrane. Biophys Chem 2006; 119:61-8. [PMID: 16223560 DOI: 10.1016/j.bpc.2005.09.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2005] [Revised: 09/11/2005] [Accepted: 09/12/2005] [Indexed: 11/26/2022]
Abstract
We have used vibrating tube densitometry to investigate the packing properties of four alkanes and a homologous series of ten alcohols in fluid-phase membranes of dimyristoyl phosphatidylcholine (DMPC). It was found that the volume change of transferring these compounds from their pure states into the membrane, DeltaV(m)(pure-->mem), was positive for small (C4-C6) 1-alkanols while it was negative for larger alcohols and all alkanes. The magnitude of DeltaV(m)(pure-->mem) ranged from about +4 cm3/mol for alcohols with an alkyl chain about half the length of the fatty acids of DMPC, to -10 to -15 cm3/mol for the alkanes and long chain alcohols. On the basis of these observations, previously published information on the structure of the membrane-solute complexes and the free volume properties of (pure) phospholipid membranes, we suggest that two effects dominate the packing properties of hydrophobic solutes in DMPC. First, perturbation of the tightly packed interfacial zone around the ester bonds and first few methylene groups of DMPC brings about a positive contribution to DeltaV(m)(pure-->mem). This effect dominates the volume behavior for alcohols like 1-butanol, 1-pentanol and 1-hexanol. More hydrophobic solutes penetrate into the membrane core, which is loosely packed. In this region, they partially occupy interstitial (or free-) volume, which bring about a denser molecular packing and generate a negative contribution to DeltaV(m)(pure-->mem).
Collapse
Affiliation(s)
- Thomas H Aagaard
- Department of Life Science and Chemistry, Roskilde University PO Box 260, DK-4000 Roskilde, Denmark
| | | | | |
Collapse
|
42
|
Bakshi MS, Singh J, Kaur G. Fluorescence study of solubilization of l-α-dilauroylphosphatidylethanolamine in the mixed micelles with monomeric and dimeric cationic surfactants. J Photochem Photobiol A Chem 2005. [DOI: 10.1016/j.jphotochem.2005.02.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
43
|
Dina OA, Hucho T, Yeh J, Malik-Hall M, Reichling DB, Levine JD. Primary afferent second messenger cascades interact with specific integrin subunits in producing inflammatory hyperalgesia. Pain 2005; 115:191-203. [PMID: 15836982 DOI: 10.1016/j.pain.2005.02.028] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2004] [Revised: 02/11/2005] [Accepted: 02/22/2005] [Indexed: 01/19/2023]
Abstract
We recently reported that hyperalgesia induced by the inflammatory mediator prostaglandin E(2) (PGE(2)) requires intact alpha1, alpha3 and beta1 integrin subunit function, whereas epinephrine-induced hyperalgesia depends on alpha5 and beta1. PGE(2)-induced hyperalgesia is mediated by protein kinase A (PKA), while epinephrine-induced hyperalgesia is mediated by a combination of PKA, protein kinase Cepsilon (PKCepsilon) and mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK). We hypothesized that inflammatory mediator-induced hyperalgesia involves specific interactions between different subsets of integrin subunits and particular second messenger species. In the present study, function-blocking anti-integrin antibodies and antisense oligodeoxynucleotides were used to elucidate these interactions in rat. Hyperalgesia produced by an activator of adenylate cyclase (forskolin) depended on alpha1, alpha3 and beta1 integrins. However, hyperalgesia induced by activation of the cascade at a point farther downstream (by cAMP analog or PKA catalytic subunit) was independent of any integrins tested. In contrast, hyperalgesia induced by a specific PKCepsilon agonist depended only on alpha5 and beta1 integrins. Hyperalgesia induced by agonism of MAPK/ERK depended on all four integrin subunits tested (alpha1, alpha3, alpha5 and beta1). Finally, disruption of lipid rafts antagonized hyperalgesia induced by PGE(2) and by forskolin, but not that induced by epinephrine. Furthermore, alpha1 integrin, but not alpha5, was present in detergent-resistant membrane fractions (which retain lipid raft components). These observations suggest that integrins play a critical role in inflammatory pain by interacting with components of second messenger cascades that mediate inflammatory hyperalgesia, and that such interaction with the PGE(2)-activated pathway may be organized by lipid rafts.
Collapse
Affiliation(s)
- Olayinka A Dina
- Department of Medicine, Division of Neuroscience and Biomedical Sciences Program, NIH Pain Center (UCSF), University of California at San Francisco, Campus Box 0440, Room C-555 521, San Francisco, CA 94143-0440, USA
| | | | | | | | | | | |
Collapse
|
44
|
Matos C, Lima JLC, Reis S, Lopes A, Bastos M. Interaction of antiinflammatory drugs with EPC liposomes: calorimetric study in a broad concentration range. Biophys J 2004; 86:946-54. [PMID: 14747330 PMCID: PMC1303942 DOI: 10.1016/s0006-3495(04)74170-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Isothermal titration calorimetry was used to characterize and quantify the partition of indomethacin and acemetacin between the bulk aqueous phase and the membrane of egg phosphatidylcholine vesicles. Significant electrostatic effects were observed due to binding of the charged drugs to the membrane, which implied the use of the Gouy-Chapman theory to calculate the interfacial concentrations. The binding/partition phenomenon was quantified in terms of the partition coefficient (K(p)), and/or the equilibrium constant (K(b)). Mathematical expressions were developed, either to encompass the electrostatic effects in the partition model, or to numerically relate partition coefficients and binding constants. Calorimetric titrations conducted under a lipid/drug ratio >100:1 lead to a constant heat release and were used to directly calculate the enthalpy of the process, DeltaH, and indirectly, DeltaG and DeltaS. As the lipid/drug ratio decreased, the constancy of reaction enthalpy was tested in the fitting process. Under low lipid/drug ratio conditions simple partition was no longer valid and the interaction phenomenon was interpreted in terms of binding isotherms. A mathematical expression was deduced for quantification of the binding constants and the number of lipid molecules associated with one drug molecule. The broad range of concentrations used stressed the biphasic nature of the interaction under study. As the lipid/drug ratio was varied, the results showed that the interaction of both drugs does not present a unique behavior in all studied regimes: the extent of the interaction, as well as the binding stoichiometry, is affected by the lipid/drug ratio. The change in these parameters reflects the biphasic behavior of the interaction-possibly the consequence of a modification of the membrane's physical properties as it becomes saturated with the drug.
Collapse
Affiliation(s)
- Carla Matos
- Rede de Química e Tecnologia/Faculdade de Ciências da Saúde, Universidade Fernando Pessoa, Porto, Portugal.
| | | | | | | | | |
Collapse
|
45
|
Meister A, Kerth A, Blume A. The interaction of n-nonyl-β-d-glucopyranoside and sodium dodecyl sulfate with DMPC and DMPG monolayers studied by infrared reflection absorption spectroscopy. Phys Chem Chem Phys 2004. [DOI: 10.1039/b410761f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
46
|
Hildebrand A, Beyer K, Neubert R, Garidel P, Blume A. Temperature dependence of the interaction of cholate and deoxycholate with fluid model membranes and their solubilization into mixed micelles. Colloids Surf B Biointerfaces 2003. [DOI: 10.1016/j.colsurfb.2003.08.001] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
47
|
Affiliation(s)
- Volker Oberle
- Department of Membrane Cell Biology, University of Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | | | | |
Collapse
|
48
|
|
49
|
Majhi PR, Blume A. Temperature-Induced Micelle-Vesicle Transitions in DMPC−SDS and DMPC−DTAB Mixtures Studied by Calorimetry and Dynamic Light Scattering. J Phys Chem B 2002. [DOI: 10.1021/jp025849b] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
50
|
Tan A, Ziegler A, Steinbauer B, Seelig J. Thermodynamics of sodium dodecyl sulfate partitioning into lipid membranes. Biophys J 2002; 83:1547-56. [PMID: 12202379 PMCID: PMC1302252 DOI: 10.1016/s0006-3495(02)73924-6] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The partition equilibria of sodium dodecyl sulfate (SDS) and lithium dodecyl sulfate between water and bilayer membranes were investigated with isothermal titration calorimetry and spectroscopic methods (light scattering, (31)P-nuclear magnetic resonance) in the temperature range of 28 degrees C to 56 degrees C. The partitioning of the dodecyl sulfate anion (DS(-)) into the bilayer membrane is energetically favored by an exothermic partition enthalpy of Delta H(O)(D) = -6.0 kcal/mol at 28 degrees C. This is in contrast to nonionic detergents where Delta H(O)(D) is usually positive. The partition enthalpy decreases linearly with increasing temperature and the molar heat capacity is Delta C(O)(P) = -50 +/- 3 cal mol(-1) K(-1). The partition isotherm is nonlinear if the bound detergent is plotted versus the free detergent concentration in bulk solution. This is caused by the electrostatic repulsion between the DS(-) ions inserted into the membrane and those free in solution near the membrane surface. The surface concentration of DS(-) immediately above the plane of binding was hence calculated with the Gouy-Chapman theory, and a strictly linear relationship was obtained between the surface concentration and the extent of DS(-) partitioning. The surface partition constant K describes the chemical equilibrium in the absence of electrostatic effects. For the SDS-membrane equilibrium K was found to be 1.2 x 10(4) M(-1) to 6 x 10(4) M(-1) for the various systems and conditions investigated, very similar to data available for nonionic detergents of the same chain length. The membrane-micelle phase diagram was also studied. Complete membrane solubilization requires a ratio of 2.2 mol SDS bound per mole of total lipid at 56 degrees C. The corresponding equilibrium concentration of SDS free in solution is C (sat)(D,F) approximately 1.7 mM and is slightly below the critical micelles concentration (CMC) = 2.1 mM (at 56 degrees C and 0.11 M buffer). Membrane saturation occurs at approximately 0.3 mol SDS per mol lipid and the equilibrium SDS concentration is C (sat)(D,F)approximately equal 2.2 mM +/- 0.6 mM. SDS translocation across the bilayer is slow at ambient temperature but increases at high temperatures.
Collapse
Affiliation(s)
- Anmin Tan
- Department of Biophysical Chemistry, Biozentrum, University of Basel, CH-4056 Basel, Switzerland
| | | | | | | |
Collapse
|