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Morin M, Björklund S, Nilsson EJ, Engblom J. Bicontinuous Cubic Liquid Crystals as Potential Matrices for Non-Invasive Topical Sampling of Low-Molecular-Weight Biomarkers. Pharmaceutics 2023; 15:2031. [PMID: 37631245 PMCID: PMC10459996 DOI: 10.3390/pharmaceutics15082031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 07/14/2023] [Accepted: 07/25/2023] [Indexed: 08/27/2023] Open
Abstract
Many skin disorders, including cancer, have inflammatory components. The non-invasive detection of related biomarkers could therefore be highly valuable for both diagnosis and follow up on the effect of treatment. This study targets the extraction of tryptophan (Trp) and its metabolite kynurenine (Kyn), two compounds associated with several inflammatory skin disorders. We furthermore hypothesize that lipid-based bicontinuous cubic liquid crystals could be efficient extraction matrices. They comprise a large interfacial area separating interconnected polar and apolar domains, allowing them to accommodate solutes with various properties. We concluded, using the extensively studied GMO-water system as test-platform, that the hydrophilic Kyn and Trp favored the cubic phase over water and revealed a preference for locating at the lipid-water interface. The interfacial area per unit volume of the matrix, as well as the incorporation of ionic molecules at the lipid-water interface, can be used to optimize the extraction of solutes with specific physicochemical characteristics. We also observed that the cubic phases formed at rather extreme water activities (>0.9) and that wearing them resulted in efficient hydration and increased permeability of the skin. Evidently, bicontinuous cubic liquid crystals constitute a promising and versatile platform for non-invasive extraction of biomarkers through skin, as well as for transdermal drug delivery.
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Affiliation(s)
- Maxim Morin
- Biofilms—Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden (S.B.); (E.J.N.)
- Department of Biomedical Science, Faculty of Health and Society, Malmö University, SE-205 06 Malmö, Sweden
| | - Sebastian Björklund
- Biofilms—Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden (S.B.); (E.J.N.)
- Department of Biomedical Science, Faculty of Health and Society, Malmö University, SE-205 06 Malmö, Sweden
| | - Emelie J. Nilsson
- Biofilms—Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden (S.B.); (E.J.N.)
- Department of Biomedical Science, Faculty of Health and Society, Malmö University, SE-205 06 Malmö, Sweden
| | - Johan Engblom
- Biofilms—Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden (S.B.); (E.J.N.)
- Department of Biomedical Science, Faculty of Health and Society, Malmö University, SE-205 06 Malmö, Sweden
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2
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Morin M, Jankovskaja S, Ruzgas T, Henricson J, Anderson CD, Brinte A, Engblom J, Björklund S. Hydrogels and Cubic Liquid Crystals for Non-Invasive Sampling of Low-Molecular-Weight Biomarkers-An Explorative In Vivo Study. Pharmaceutics 2022; 14:313. [PMID: 35214046 PMCID: PMC8879558 DOI: 10.3390/pharmaceutics14020313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 01/20/2022] [Accepted: 01/25/2022] [Indexed: 02/05/2023] Open
Abstract
The molecular composition of human skin is altered due to diseases, which can be utilized for non-invasive sampling of biomarkers and disease diagnostics. For this to succeed, it is crucial to identify a sampling formulation with high extraction efficiency and reproducibility. Highly hydrated skin is expected to be optimal for increased diffusion of low-molecular-weight biomarkers, enabling efficient extraction as well as enhanced reproducibility as full hydration represents a well-defined endpoint. Here, the aim was to explore water-based formulations with high water activities, ensuring satisfactory skin hydration, for non-invasive sampling of four analytes that may serve as potential biomarkers, namely tryptophan, tyrosine, phenylalanine, and kynurenine. The included formulations consisted of two hydrogels (chitosan and agarose) and two different liquid crystalline cubic phases based on the polar lipid glycerol monooleate, which were all topically applied for 2 h on 35 healthy subjects in vivo. The skin status of all sampling sites was assessed by electrical impedance spectroscopy and transepidermal water loss, enabling explorative correlations between biophysical properties and analyte abundancies. Taken together, all formulations resulted in the successful and reproducible collection of the investigated biomarkers. Still, the cubic phases had an extraction capacity that was approximately two times higher compared to the hydrogels.
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Affiliation(s)
- Maxim Morin
- Department of Biomedical Sciences, Faculty of Health and Society, Malmö University, SE-205 06 Malmö, Sweden; (M.M.); (S.J.); (T.R.); (J.E.)
- Biofilms–Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden
| | - Skaidre Jankovskaja
- Department of Biomedical Sciences, Faculty of Health and Society, Malmö University, SE-205 06 Malmö, Sweden; (M.M.); (S.J.); (T.R.); (J.E.)
- Biofilms–Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden
| | - Tautgirdas Ruzgas
- Department of Biomedical Sciences, Faculty of Health and Society, Malmö University, SE-205 06 Malmö, Sweden; (M.M.); (S.J.); (T.R.); (J.E.)
- Biofilms–Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden
| | - Joakim Henricson
- Division of Clinical Chemistry and Pharmacology, Department of Biomedical and Clinical Sciences, Faculty of Health Sciences, Linköping University, SE-581 83 Linköping, Sweden;
- Department of Emergency Medicine, Local Health Care Services in Central Östergötland, SE-581 85 Linköping, Sweden
| | - Chris D. Anderson
- Division of Cell Biology, Department of Biomedical and Clinical Sciences, Faculty of Health Sciences, Linköping University, SE-581 83 Linköping, Sweden;
| | - Anders Brinte
- ImaGene-iT, Medicon Village, SE-223 63 Lund, Sweden;
| | - Johan Engblom
- Department of Biomedical Sciences, Faculty of Health and Society, Malmö University, SE-205 06 Malmö, Sweden; (M.M.); (S.J.); (T.R.); (J.E.)
- Biofilms–Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden
| | - Sebastian Björklund
- Department of Biomedical Sciences, Faculty of Health and Society, Malmö University, SE-205 06 Malmö, Sweden; (M.M.); (S.J.); (T.R.); (J.E.)
- Biofilms–Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden
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3
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Morin M, Björklund S, Jankovskaja S, Moore K, Delgado-Charro MB, Ruzgas T, Guy RH, Engblom J. Reverse Iontophoretic Extraction of Skin Cancer-Related Biomarkers. Pharmaceutics 2021; 14:79. [PMID: 35056976 PMCID: PMC8778044 DOI: 10.3390/pharmaceutics14010079] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 12/16/2021] [Accepted: 12/22/2021] [Indexed: 11/16/2022] Open
Abstract
Non-invasive methods for early diagnosis of skin cancer are highly valued. One possible approach is to monitor relevant biomarkers such as tryptophan (Trp) and kynurenine (Kyn), on the skin surface. The primary aim of this in vitro investigation was, therefore, to examine whether reverse iontophoresis (RI) can enhance the extraction of Trp and Kyn, and to demonstrate how the Trp/Kyn ratio acquired from the skin surface reflects that in the epidermal tissue. The study also explored whether the pH of the receiver medium impacted on extraction efficiency, and assessed the suitability of a bicontinuous cubic liquid crystal as an alternative to a simple buffer solution for this purpose. RI substantially enhanced the extraction of Trp and Kyn, in particular towards the cathode. The Trp/Kyn ratio obtained on the surface matched that in the viable skin. Increasing the receiver solution pH from 4 to 9 improved extraction of both analytes, but did not significantly change the Trp/Kyn ratio. RI extraction of Trp and Kyn into the cubic liquid crystal was comparable to that achieved with simple aqueous receiver solutions. We conclude that RI offers a potential for non-invasive sampling of low-molecular weight biomarkers and further investigations in vivo are therefore warranted.
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Affiliation(s)
- Maxim Morin
- Department of Biomedical Science, Faculty of Health and Society, Malmö University, SE-205 06 Malmö, Sweden; (S.B.); (S.J.); (T.R.)
- Biofilms—Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden
| | - Sebastian Björklund
- Department of Biomedical Science, Faculty of Health and Society, Malmö University, SE-205 06 Malmö, Sweden; (S.B.); (S.J.); (T.R.)
- Biofilms—Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden
| | - Skaidre Jankovskaja
- Department of Biomedical Science, Faculty of Health and Society, Malmö University, SE-205 06 Malmö, Sweden; (S.B.); (S.J.); (T.R.)
- Biofilms—Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden
| | - Kieran Moore
- Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK; (K.M.); (M.B.D.-C.); (R.H.G.)
| | - Maria Begoña Delgado-Charro
- Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK; (K.M.); (M.B.D.-C.); (R.H.G.)
| | - Tautgirdas Ruzgas
- Department of Biomedical Science, Faculty of Health and Society, Malmö University, SE-205 06 Malmö, Sweden; (S.B.); (S.J.); (T.R.)
- Biofilms—Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden
| | - Richard H. Guy
- Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK; (K.M.); (M.B.D.-C.); (R.H.G.)
| | - Johan Engblom
- Department of Biomedical Science, Faculty of Health and Society, Malmö University, SE-205 06 Malmö, Sweden; (S.B.); (S.J.); (T.R.)
- Biofilms—Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden
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Milak S, Chemelli A, Glatter O, Zimmer A. Vancomycin Loaded Glycerol Monooleate Liquid Crystalline Phases Modified with Surfactants. Pharmaceutics 2020; 12:E521. [PMID: 32521610 PMCID: PMC7356114 DOI: 10.3390/pharmaceutics12060521] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 05/05/2020] [Accepted: 05/26/2020] [Indexed: 11/27/2022] Open
Abstract
The influence of two tuning agents, polyglycerol ester (PE) and triblock copolymer (TC), on the properties of glycerol monooleate (MO) liquid crystalline phase (LCP) was investigated to achieve the therapeutic concentration of vancomycin hydrochloride (VHCl) into the eye, topically during 60 min (1 h) and intravitreally during 2880 min (48 h). Different techniques were used to elucidate the impact of surfactants on the structure of the LCP: polarized light microscopy (PLM), small-angle X-ray scattering (SAXS), and in vitro release tests I and II (simulating local and intravitreal application in the eye). The structure analysis by SAXS depicts that the inclusion of PE into the MO LCP provided partial transition of a hexagonal phase into a lamellar phase, and TC induced a partial transition of a hexagonal phase into an LCP which identification was difficult. The LCP modulated with PE and TC demonstrated different VHCl's release patterns and were evaluated by comparing our release data with the literature data. The comparison indicated that the LCP modulated with 30% w/w PE could be a promising VHCl delivery system intravitreally during 2880 min.
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Affiliation(s)
- Spomenka Milak
- Department of Pharmaceutical Technology and Biopharmacy, Institute of Pharmaceutical Sciences, University of Graz, NAWI Graz, Universitätsplatz 1, 8010 Graz, Austria;
| | - Angela Chemelli
- Institute of Inorganic Chemistry, Graz University of Technology, 8010 Graz, Austria; (A.C.); (O.G.)
| | - Otto Glatter
- Institute of Inorganic Chemistry, Graz University of Technology, 8010 Graz, Austria; (A.C.); (O.G.)
| | - Andreas Zimmer
- Department of Pharmaceutical Technology and Biopharmacy, Institute of Pharmaceutical Sciences, University of Graz, NAWI Graz, Universitätsplatz 1, 8010 Graz, Austria;
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5
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Baez-Cotto CM, Jackson GL, Mahanthappa MK. Aqueous Lyotropic Mesophase Behavior of Gemini Dicarboxylate Surfactants Swollen with n-Decane. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:2307-2321. [PMID: 32101436 DOI: 10.1021/acs.langmuir.9b03408] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We report detailed small-angle X-ray scattering (SAXS) studies of the impact of variable n-decane loadings on the lyotropic liquid crystalline (LLC) phase behaviors of homologous bis(tetramethylammonium) gemini didecanoate surfactants TMA-7x, which derive from dimerizing decanoic acid through its α-carbon with hydrocarbyl linkers -(CH2)x- where x = 3, 4, 5, and 6. TMA-7x amphiphiles with x = 3 or 5 exhibit a strong propensity to form normal double gyroid (G) LLC network mesophases over wide surfactant hydration ranges, as compared to homologues with x = 4 or 6. On swelling aqueous TMA-7x LLC mesophases with up to 35 wt % n-decane, we demonstrate that odd-carbon linked surfactants (x = 3 or 5) form G and normal double diamond (D) phases over wide water concentration windows with T = 22-100 °C. Complementary studies of decane-swollen TMA-7x (x = 4 or 6) aqueous LLCs instead demonstrate significantly diminished network phase stability, in favor of hexagonally-packed cylinder phases and a zoo of complex quasispherical micelle packings, which include micellar C14 and C15 Laves phases (P63/mmc and Fd3(-)m symmetries, respectively) and high-symmetry hexagonally close packed (HCP) and body-centered cubic (BCC) arrangements. These rich phase behaviors are rationalized in terms of linker length parity-dependent surfactant conformations and the delicate free energy balance that guides the packing of these geometrically anisotropic amphiphiles by minimizing unfavorable water-hydrophobic contacts, maximizing ionic surfactant-headgroup counterion solvation with minimal local variations, and maximizing electrostatic cohesion within these supramolecular assemblies.
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Affiliation(s)
- Carlos M Baez-Cotto
- Department of Chemistry, University of Minnesota, 207 Pleasant St. S. E., Minneapolis, Minnesota 55455, United States
| | - Grayson L Jackson
- Department of Chemistry, University of Wisconsin, 1101 University Ave., Madison, Wisconsin 53706, United States
| | - Mahesh K Mahanthappa
- Department of Chemistry, University of Minnesota, 207 Pleasant St. S. E., Minneapolis, Minnesota 55455, United States
- Department of Chemical Engineering & Materials Science, University of Minnesota, 421 Washington Ave. S. E., Minneapolis, Minnesota 55455, United States
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6
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Park SH, Zhang H, Kim JC. Monoolein cubic phase containing azobenzene and its UV/visible light irradiation-dependent release property. J DISPER SCI TECHNOL 2018. [DOI: 10.1080/01932691.2017.1326311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Seok Ho Park
- Department of Medical Biomaterials Engineering, College of Biomedical Science and Institute of Bioscience and Biotechnology, Kangwon National University, Chuncheon, Kangwon-do, Republic of Korea
| | - Hong Zhang
- Department of Medical Biomaterials Engineering, College of Biomedical Science and Institute of Bioscience and Biotechnology, Kangwon National University, Chuncheon, Kangwon-do, Republic of Korea
| | - Jin-Chul Kim
- Department of Medical Biomaterials Engineering, College of Biomedical Science and Institute of Bioscience and Biotechnology, Kangwon National University, Chuncheon, Kangwon-do, Republic of Korea
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7
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Crystallization under an External Electric Field: A Case Study of Glucose Isomerase. CRYSTALS 2017. [DOI: 10.3390/cryst7070206] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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8
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Grippo V, Pawłowska J, Biernat JF, Bilewicz R. Synergic Effect of Naphthylated Carbon Nanotubes and Gold Nanoparticles on Catalytic Performance of Hybrid Films Containing Bilirubin Oxidase for the Dioxygen Reduction. ELECTROANAL 2016. [DOI: 10.1002/elan.201600511] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Valentina Grippo
- University of Warsaw; Faculty of Chemistry; Pasteura 1 02-093 Warsaw Poland
| | - Joanna Pawłowska
- University of Warsaw; Faculty of Chemistry; Pasteura 1 02-093 Warsaw Poland
| | - Jan F. Biernat
- Gdansk University of Technology; Faculty of Chemistry; Narutowicza 11/12 80-233 Gdansk Poland
| | - Renata Bilewicz
- University of Warsaw; Faculty of Chemistry; Pasteura 1 02-093 Warsaw Poland
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9
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Wu W, Nogly P, Rheinberger J, Kick LM, Gati C, Nelson G, Deupi X, Standfuss J, Schertler G, Panneels V. Batch crystallization of rhodopsin for structural dynamics using an X-ray free-electron laser. Acta Crystallogr F Struct Biol Commun 2015; 71:856-60. [PMID: 26144230 PMCID: PMC4498706 DOI: 10.1107/s2053230x15009966] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 05/22/2015] [Indexed: 11/11/2022] Open
Abstract
Rhodopsin is a membrane protein from the G protein-coupled receptor family. Together with its ligand retinal, it forms the visual pigment responsible for night vision. In order to perform ultrafast dynamics studies, a time-resolved serial femtosecond crystallography method is required owing to the nonreversible activation of rhodopsin. In such an approach, microcrystals in suspension are delivered into the X-ray pulses of an X-ray free-electron laser (XFEL) after a precise photoactivation delay. Here, a millilitre batch production of high-density microcrystals was developed by four methodical conversion steps starting from known vapour-diffusion crystallization protocols: (i) screening the low-salt crystallization conditions preferred for serial crystallography by vapour diffusion, (ii) optimization of batch crystallization, (iii) testing the crystal size and quality using second-harmonic generation (SHG) imaging and X-ray powder diffraction and (iv) production of millilitres of rhodopsin crystal suspension in batches for serial crystallography tests; these crystals diffracted at an XFEL at the Linac Coherent Light Source using a liquid-jet setup.
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Affiliation(s)
- Wenting Wu
- Laboratory for Biomolecular Research, Paul Scherrer Institute, OFLC/103, 5232 Villigen-PSI, Switzerland
| | - Przemyslaw Nogly
- Laboratory for Biomolecular Research, Paul Scherrer Institute, OFLC/103, 5232 Villigen-PSI, Switzerland
| | - Jan Rheinberger
- Laboratory for Biomolecular Research, Paul Scherrer Institute, OFLC/103, 5232 Villigen-PSI, Switzerland
| | - Leonhard M. Kick
- Laboratory for Biomolecular Research, Paul Scherrer Institute, OFLC/103, 5232 Villigen-PSI, Switzerland
| | - Cornelius Gati
- Laboratory for Biomolecular Research, Paul Scherrer Institute, OFLC/103, 5232 Villigen-PSI, Switzerland
| | - Garrett Nelson
- Laboratory for Biomolecular Research, Paul Scherrer Institute, OFLC/103, 5232 Villigen-PSI, Switzerland
| | - Xavier Deupi
- Laboratory for Biomolecular Research, Paul Scherrer Institute, OFLC/103, 5232 Villigen-PSI, Switzerland
| | - Jörg Standfuss
- Laboratory for Biomolecular Research, Paul Scherrer Institute, OFLC/103, 5232 Villigen-PSI, Switzerland
| | - Gebhard Schertler
- Laboratory for Biomolecular Research, Paul Scherrer Institute, OFLC/103, 5232 Villigen-PSI, Switzerland
| | - Valérie Panneels
- Laboratory for Biomolecular Research, Paul Scherrer Institute, OFLC/103, 5232 Villigen-PSI, Switzerland
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10
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Methodological advances: the unsung heroes of the GPCR structural revolution. Nat Rev Mol Cell Biol 2015; 16:69-81. [DOI: 10.1038/nrm3933] [Citation(s) in RCA: 157] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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11
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Fenalti G, Abola EE, Wang C, Wu B, Cherezov V. Fluorescence Recovery After Photobleaching in Lipidic Cubic Phase (LCP-FRAP). Methods Enzymol 2015; 557:417-37. [DOI: 10.1016/bs.mie.2014.12.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
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12
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Zhang H, Kim JC. Preparation and photothermal induced release from cubic phase containing gold nanoparticle. Colloids Surf A Physicochem Eng Asp 2015. [DOI: 10.1016/j.colsurfa.2014.10.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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13
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Stoilova-McPhie S, Grushin K, Dalm D, Miller J. Lipid nanotechnologies for structural studies of membrane-associated proteins. Proteins 2014; 82:2902-9. [PMID: 24957666 PMCID: PMC5292012 DOI: 10.1002/prot.24631] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2014] [Revised: 06/04/2014] [Accepted: 06/08/2014] [Indexed: 11/09/2022]
Abstract
We present a methodology of lipid nanotubes (LNT) and nanodisks technologies optimized in our laboratory for structural studies of membrane-associated proteins at close to physiological conditions. The application of these lipid nanotechnologies for structure determination by cryo-electron microscopy (cryo-EM) is fundamental for understanding and modulating their function. The LNTs in our studies are single bilayer galactosylceramide based nanotubes of ∼20 nm inner diameter and a few microns in length, that self-assemble in aqueous solutions. The lipid nanodisks (NDs) are self-assembled discoid lipid bilayers of ∼10 nm diameter, which are stabilized in aqueous solutions by a belt of amphipathic helical scaffold proteins. By combining LNT and ND technologies, we can examine structurally how the membrane curvature and lipid composition modulates the function of the membrane-associated proteins. As proof of principle, we have engineered these lipid nanotechnologies to mimic the activated platelet's phosphtaidylserine rich membrane and have successfully assembled functional membrane-bound coagulation factor VIII in vitro for structure determination by cryo-EM. The macromolecular organization of the proteins bound to ND and LNT are further defined by fitting the known atomic structures within the calculated three-dimensional maps. The combination of LNT and ND technologies offers a means to control the design and assembly of a wide range of functional membrane-associated proteins and complexes for structural studies by cryo-EM. The presented results confirm the suitability of the developed methodology for studying the functional structure of membrane-associated proteins, such as the coagulation factors, at a close to physiological environment.
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Affiliation(s)
- Svetla Stoilova-McPhie
- Department of Neuroscience and Cell Biology, The University of Texas Medical Branch, 301 University Blvd, Galveston, Texas, 77555; Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch, 301 University Blvd, Galveston, Texas, 77555
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14
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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]
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15
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Negrini R, Mezzenga R. Diffusion, molecular separation, and drug delivery from lipid mesophases with tunable water channels. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:16455-62. [PMID: 23116138 DOI: 10.1021/la303833s] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Lyotropic liquid crystals characterized by a bicontinuous cubic phase (BCP) have a structure characterized by interpenetrated water channels following triply periodic minimal surfaces, which can be stable in excess water conditions and thus suitable in a multitude of applications. The control of the water channels size in these systems has a direct impact on their use for drug delivery, crystallization, and membrane separation processes. In this work we carry out systematic diffusion studies to show how the control on the water channel dimensions directly correlates with the release and separation performance of bicontinuous cubic phases. Specifically, we tune the water channels diameter of the monolinolein/water system by adding different amounts of sucrose stearate, which, having hydration-enhancing properties, can shift the boundaries of the phase diagram. We then design a model bicontinuous cubic phase lipidic membrane of the Im3m space group, having a sugar ester to monolinolein ratio of 20%, and we follow the diffusion within its water channels, by using molecules that differ systematically in size and molecular conformation, and we demonstrate, for each class of molecules, a diffusion-enhanced process upon increase of the water channel diameter. Finally, we also show the ability of the bicontinuous cubic phase to efficiently and selectively separate nanoparticles of a target size, by choosing an amount of sucrose stearate for which the water channel diameter and the nanoparticle dimensions match, demonstrating the possible use of these systems as filtering membranes of tunable molecular cutoff.
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Affiliation(s)
- Renata Negrini
- Food and Soft Materials Science, Institute of Food, Nutrition & Health, ETH Zurich, Schmelzbergstrasse 9, CH-8092 Zürich, Switzerland
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16
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Robertson JWF, Kasianowicz JJ, Banerjee S. Analytical Approaches for Studying Transporters, Channels and Porins. Chem Rev 2012; 112:6227-49. [DOI: 10.1021/cr300317z] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Joseph W. F. Robertson
- Physical Measurement Laboratory,
National Institute of Standards and Technology, Gaithersburg, Maryland
20899, United States
| | - John J. Kasianowicz
- Physical Measurement Laboratory,
National Institute of Standards and Technology, Gaithersburg, Maryland
20899, United States
| | - Soojay Banerjee
- National
Institute of Neurological
Disorders and Stroke, Bethesda, Maryland 20824, United States
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17
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Sagnella SM, Conn CE, Krodkiewska I, Drummond CJ. Nonionic diethanolamide amphiphiles with saturated hydrocarbon chains: Neat crystalline and lyotropic liquid crystalline phase behavior. J Colloid Interface Sci 2012; 385:87-95. [DOI: 10.1016/j.jcis.2012.06.077] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Revised: 06/25/2012] [Accepted: 06/26/2012] [Indexed: 11/25/2022]
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18
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Mondal J, Mahanthappa M, Yethiraj A. Self-Assembly of Gemini Surfactants: A Computer Simulation Study. J Phys Chem B 2012; 117:4254-62. [DOI: 10.1021/jp304933k] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jagannath Mondal
- Department
of Chemistry, University of Wisconsin,
Madison, Wisconsin 53706, United States
| | - Mahesh Mahanthappa
- Department
of Chemistry, University of Wisconsin,
Madison, Wisconsin 53706, United States
| | - Arun Yethiraj
- Department
of Chemistry, University of Wisconsin,
Madison, Wisconsin 53706, United States
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19
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Darmanin C, Conn CE, Newman J, Mulet X, Seabrook SA, Liang YL, Hawley A, Kirby N, Varghese JN, Drummond CJ. High-throughput production and structural characterization of libraries of self-assembly lipidic cubic phase materials. ACS COMBINATORIAL SCIENCE 2012; 14:247-52. [PMID: 22428998 DOI: 10.1021/co2001718] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A protocol is presented for the high-throughput (HT) production of lyotropic liquid crystalline phases from libraries of lipids and lipid mixtures using standard liquid dispensing robotics, implementing methods that circumvent the problems traditionally associated with handling the highly viscous cubic phase. In addition, the ability to structurally characterize lipidic phases and assess functionality for membrane proteins contained within cubic phases, in a HT manner, is demonstrated. The techniques are combined and exemplified using the application of membrane protein crystallization within lipidic cubic phases.
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Affiliation(s)
- Connie Darmanin
- CSIRO Materials Science and Engineering, 343 Royal Parade, Parkville,
Victoria 3052, Australia
| | - Charlotte E. Conn
- CSIRO Materials Science and Engineering, Private Bag 10, Clayton South
MDC, Victoria 3169, Australia
| | - Janet Newman
- CSIRO Materials Science and Engineering, 343 Royal Parade, Parkville,
Victoria 3052, Australia
| | - Xavier Mulet
- CSIRO Materials Science and Engineering, Private Bag 10, Clayton South
MDC, Victoria 3169, Australia
- Drug Delivery, Disposition and
Dynamics, Monash Institute of Pharmaceutical Sciences, 381 Royal Parade, Parkville Victoria 3052, Australia
| | - Shane A. Seabrook
- CSIRO Materials Science and Engineering, 343 Royal Parade, Parkville,
Victoria 3052, Australia
| | - Yi-Lynn Liang
- CSIRO Materials Science and Engineering, 343 Royal Parade, Parkville,
Victoria 3052, Australia
- ARC Centre of Excellence for Coherent
X-ray Science, La Trobe University, Bundoora,
Victoria 3086, Australia
| | - Adrian Hawley
- Australian Synchrotron, 800 Blackburn
Rd, Clayton, Victoria 3168, Australia
| | - Nigel Kirby
- Australian Synchrotron, 800 Blackburn
Rd, Clayton, Victoria 3168, Australia
| | - Joseph N. Varghese
- CSIRO Materials Science and Engineering, 343 Royal Parade, Parkville,
Victoria 3052, Australia
| | - Calum J. Drummond
- CSIRO Materials Science and Engineering, Private Bag 10, Clayton South
MDC, Victoria 3169, Australia
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20
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Fong C, Le T, Drummond CJ. Lyotropic liquid crystal engineering–ordered nanostructured small molecule amphiphileself-assembly materials by design. Chem Soc Rev 2012; 41:1297-322. [DOI: 10.1039/c1cs15148g] [Citation(s) in RCA: 235] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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21
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Hunter MS, Fromme P. Toward structure determination using membrane-protein nanocrystals and microcrystals. Methods 2011; 55:387-404. [PMID: 22197730 DOI: 10.1016/j.ymeth.2011.12.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Revised: 12/03/2011] [Accepted: 12/14/2011] [Indexed: 02/05/2023] Open
Abstract
Membrane proteins are very important for all living cells, being involved in respiration, photosynthesis, cellular uptake and signal transduction, amongst other vital functions. However, less than 300 unique membrane protein structures have been determined to date, often due to difficulties associated with the growth of sufficiently large and well-ordered crystals. This work has been focused on showing the first proof of concept for using membrane protein nanocrystals and microcrystals for high-resolution structure determination. Upon determining that crystals of the membrane protein Photosystem I, which is the largest and most complex membrane protein crystallized to date, exist with only 100 unit cells with sizes of less than 200 nm on an edge, work was done to develop a technique that could exploit the growth of the Photosystem I nanocrystals and microcrystals. Femtosecond X-ray protein nanocrystallography was developed for use at the first high-energy X-ray free electron laser, the LCLS at SLAC National Accelerator Laboratory, in which a liquid jet brought fully-hydrated Photosystem I nanocrystals into the interaction region of the pulsed X-ray source. Diffraction patterns were recorded from millions of individual PSI nanocrystals and data from thousands of different, randomly oriented crystallites were integrated using Monte Carlo integration of the peak intensities. The short pulses (∼70fs) provided by the LCLS allowed the possibility to collect the diffraction data before the onset of radiation damage, exploiting the diffract-before-destroy principle. During the initial experiments at the AMO beamline using 6.9-Å wavelength, Bragg peaks were recorded to 8.5-Å resolution, and an electron-density map was determined that did not show any effects of X-ray-induced radiation damage [94]. Many additional techniques still need to be developed to explore the femtosecond nanocrystallography technique for experimental phasing and time-resolved X-ray crystallography experiments. The first proof-of-principle results for the femtosecond nanocrystallography technique indicate the incredible potential of the technique to offer a new route to the structure determination of membrane proteins.
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Affiliation(s)
- Mark S Hunter
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287, USA.
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22
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Wallace E, Dranow D, Laible PD, Christensen J, Nollert P. Monoolein lipid phases as incorporation and enrichment materials for membrane protein crystallization. PLoS One 2011; 6:e24488. [PMID: 21909395 PMCID: PMC3164205 DOI: 10.1371/journal.pone.0024488] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2011] [Accepted: 08/11/2011] [Indexed: 11/19/2022] Open
Abstract
The crystallization of membrane proteins in amphiphile-rich materials such as lipidic cubic phases is an established methodology in many structural biology laboratories. The standard procedure employed with this methodology requires the generation of a highly viscous lipidic material by mixing lipid, for instance monoolein, with a solution of the detergent solubilized membrane protein. This preparation is often carried out with specialized mixing tools that allow handling of the highly viscous materials while minimizing dead volume to save precious membrane protein sample. The processes that occur during the initial mixing of the lipid with the membrane protein are not well understood. Here we show that the formation of the lipidic phases and the incorporation of the membrane protein into such materials can be separated experimentally. Specifically, we have investigated the effect of different initial monoolein-based lipid phase states on the crystallization behavior of the colored photosynthetic reaction center from Rhodobacter sphaeroides. We find that the detergent solubilized photosynthetic reaction center spontaneously inserts into and concentrates in the lipid matrix without any mixing, and that the initial lipid material phase state is irrelevant for productive crystallization. A substantial in-situ enrichment of the membrane protein to concentration levels that are otherwise unobtainable occurs in a thin layer on the surface of the lipidic material. These results have important practical applications and hence we suggest a simplified protocol for membrane protein crystallization within amphiphile rich materials, eliminating any specialized mixing tools to prepare crystallization experiments within lipidic cubic phases. Furthermore, by virtue of sampling a membrane protein concentration gradient within a single crystallization experiment, this crystallization technique is more robust and increases the efficiency of identifying productive crystallization parameters. Finally, we provide a model that explains the incorporation of the membrane protein from solution into the lipid phase via a portal lamellar phase.
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Affiliation(s)
- Ellen Wallace
- Emerald BioStructures, Bainbridge Island, Washington, United States of America
| | - David Dranow
- Emerald BioStructures, Bainbridge Island, Washington, United States of America
| | - Philip D. Laible
- Biosciences Division, Argonne National Laboratory, Argonne, Illinois, United States of America
| | - Jeff Christensen
- Emerald BioStructures, Bainbridge Island, Washington, United States of America
| | - Peter Nollert
- Emerald BioStructures, Bainbridge Island, Washington, United States of America
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23
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Zabara A, Amar-Yuli I, Mezzenga R. Tuning in-meso-crystallized lysozyme polymorphism by lyotropic liquid crystal symmetry. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:6418-6425. [PMID: 21506575 DOI: 10.1021/la200710p] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Lipid-based lyotropic liquid crystals (LLCs) show great potential for applications in fields as diverse as food technology, cosmetics, pharmaceutics, or structural biology. Recently, these systems have provided a viable alternative to the difficult process of membrane protein crystallization, owing to their similarities with cell membranes. Nonetheless, the process of in-meso crystallization of proteins still remains poorly understood. In this study, we demonstrate that in-meso crystal morphologies of lysozyme (LSZ), a model hydrophilic protein, can be controlled by both the composition and symmetry of the mesophase, inferring a possible general influence of the LLC space group on the protein crystal polymorphism. Lysozyme was crystallized in-meso from three common LLC phases (lamellar, inverse hexagonal, and inverse bicontinuous cubic) composed of monolinolein and water. Different mixing ratios of mesophase to crystallization buffer were used in order to tune crystallization both in the bulk mesophase and in excess water conditions. Two distinct mechanisms of crystallization were shown to take place depending on available water in the mesophases. In the bulk mesophases, protein nuclei form and grow within structural defects of the mesophase and partially dehydrate the system inducing order-to-order transitions of the liquid crystalline phase toward stable symmetries in conditions of lower hydration. The formed protein crystals eventually macrophase separate from the mesophase allowing the system to reach its final symmetry. On the other hand, when excess water is available, protein molecules diffuse from the water channels into the excess water, where the crystallization process can take place freely, and with little to no effect on the structure and symmetry of the lyotropic liquid crystals.
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Affiliation(s)
- Alexandru Zabara
- ETH Zurich, Food & Soft Materials Science, Institute of Food, Nutrition & Health Schmelzbergstrasse 9, LFO E23, 8092 Zürich, Switzerland
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24
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A hydrogen peroxide biosensor based on the direct electron transfer of hemoglobin encapsulated in liquid-crystalline cubic phase on electrode. Colloids Surf B Biointerfaces 2011; 82:359-64. [DOI: 10.1016/j.colsurfb.2010.09.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Revised: 09/04/2010] [Accepted: 09/07/2010] [Indexed: 11/18/2022]
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25
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Sagnella SM, Conn CE, Krodkiewska I, Drummond CJ. Nonionic diethanolamide amphiphiles with isoprenoid-type hydrocarbon chains: thermotropic and lyotropic liquid crystalline phase behaviour. Phys Chem Chem Phys 2011; 13:17511-20. [DOI: 10.1039/c1cp21845j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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26
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Pabst G, Kucerka N, Nieh MP, Rheinstädter MC, Katsaras J. Applications of neutron and X-ray scattering to the study of biologically relevant model membranes. Chem Phys Lipids 2010; 163:460-79. [PMID: 20361949 DOI: 10.1016/j.chemphyslip.2010.03.010] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2010] [Revised: 03/23/2010] [Accepted: 03/24/2010] [Indexed: 11/19/2022]
Abstract
Scattering techniques, in particular electron, neutron and X-ray scattering have played a major role in elucidating the static and dynamic structure of biologically relevant membranes. Importantly, neutron and X-ray scattering have evolved to address new sample preparations that better mimic biological membranes. In this review, we will report on some of the latest model membrane results, and the neutron and X-ray techniques that were used to obtain them.
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Affiliation(s)
- G Pabst
- Institute of Biophysics and Nanosystems Research, Austrian Academy of Sciences, A-8042 Graz, Austria
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27
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Sagnella SM, Conn CE, Krodkiewska I, Moghaddam M, Drummond CJ. Endogenous Nonionic Saturated Monoethanolamide Lipids: Solid State, Lyotropic Liquid Crystalline, and Solid Lipid Nanoparticle Dispersion Behavior. J Phys Chem B 2010; 114:1729-37. [DOI: 10.1021/jp910578h] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Sharon M. Sagnella
- CSIRO Molecular and Health Technologies, P.O. Box 184, North Ryde, New South Wales 1670, Australia, CSIRO Molecular and Health Technologies, Private Bag 10, Clayton, Victoria 3169, Australia, and CSIRO Materials Science and Engineering, Bag 33, Clayton South, Victoria 3169, Australia
| | - Charlotte E. Conn
- CSIRO Molecular and Health Technologies, P.O. Box 184, North Ryde, New South Wales 1670, Australia, CSIRO Molecular and Health Technologies, Private Bag 10, Clayton, Victoria 3169, Australia, and CSIRO Materials Science and Engineering, Bag 33, Clayton South, Victoria 3169, Australia
| | - Irena Krodkiewska
- CSIRO Molecular and Health Technologies, P.O. Box 184, North Ryde, New South Wales 1670, Australia, CSIRO Molecular and Health Technologies, Private Bag 10, Clayton, Victoria 3169, Australia, and CSIRO Materials Science and Engineering, Bag 33, Clayton South, Victoria 3169, Australia
| | - Minoo Moghaddam
- CSIRO Molecular and Health Technologies, P.O. Box 184, North Ryde, New South Wales 1670, Australia, CSIRO Molecular and Health Technologies, Private Bag 10, Clayton, Victoria 3169, Australia, and CSIRO Materials Science and Engineering, Bag 33, Clayton South, Victoria 3169, Australia
| | - Calum J. Drummond
- CSIRO Molecular and Health Technologies, P.O. Box 184, North Ryde, New South Wales 1670, Australia, CSIRO Molecular and Health Technologies, Private Bag 10, Clayton, Victoria 3169, Australia, and CSIRO Materials Science and Engineering, Bag 33, Clayton South, Victoria 3169, Australia
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28
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In Cubo Crystallization of Membrane Proteins. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/b978-0-12-381266-7.00009-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
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29
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Mishraki T, Libster D, Aserin A, Garti N. Lysozyme entrapped within reverse hexagonal mesophases: Physical properties and structural behavior. Colloids Surf B Biointerfaces 2010; 75:47-56. [DOI: 10.1016/j.colsurfb.2009.08.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2009] [Revised: 08/06/2009] [Accepted: 08/06/2009] [Indexed: 11/12/2022]
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30
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Abstract
Recent advances in the crystallography of bacteriorhodopsin, the light-driven proton pump, have yielded structural models for all intermediates of the photochemical cycle. For seven of the species, X-ray diffraction data were collected from trapped photostationary states in crystals, and for the two remaining ones the structures of selected mutants are available. The changes of the retinal chromophore, protein and bound water describe, at an atomic level, how accommodation of the twisted photoisomerized retinal to its binding site causes de-protonation of the retinal Schiff base and initiates cascades of gradual conformational rearrangements of the protein. One cascade propagates in the extracellular direction and results in proton release, and the other in the cytoplasmic direction and results in side-chain and main-chain rearrangements, formation of a chain of hydrogen-bonded water, and proton uptake from the bulk. Such local-global conformational coupling, with gradual spreading of a local perturbation over the rest of the protein, might be the uniting principle of transporters and receptors.
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Affiliation(s)
- Janos K Lanyi
- Department of Physiology and Biophysics, University of California, Irvine, CA 92697, USA.
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31
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Hato M, Yamashita J, Shiono M. Aqueous Phase Behavior of Lipids with Isoprenoid Type Hydrophobic Chains. J Phys Chem B 2009; 113:10196-209. [DOI: 10.1021/jp902883q] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Masakatsu Hato
- Nanotechnology Research Institute, AIST, Tsukuba Central-5, Higashi 1-1-1, Tsukuba, Ibaraki 305-8565, Japan, and New Business Development Division, Kuraray Co., Ltd, 1-1-3, Otemachi, Chiyoda-ku, Tokyo 100-8115, Japan
| | - Jun Yamashita
- Nanotechnology Research Institute, AIST, Tsukuba Central-5, Higashi 1-1-1, Tsukuba, Ibaraki 305-8565, Japan, and New Business Development Division, Kuraray Co., Ltd, 1-1-3, Otemachi, Chiyoda-ku, Tokyo 100-8115, Japan
| | - Manzo Shiono
- Nanotechnology Research Institute, AIST, Tsukuba Central-5, Higashi 1-1-1, Tsukuba, Ibaraki 305-8565, Japan, and New Business Development Division, Kuraray Co., Ltd, 1-1-3, Otemachi, Chiyoda-ku, Tokyo 100-8115, Japan
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32
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Perry SL, Roberts GW, Tice JD, Gennis RB, Kenis PJA. Microfluidic Generation of Lipidic Mesophases for Membrane Protein Crystallization. CRYSTAL GROWTH & DESIGN 2009; 9:2566-2569. [PMID: 20161169 PMCID: PMC2721472 DOI: 10.1021/cg900289d] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
We report on a microfluidic method for the formation of aqueous/lipid mesophases to enable screening of suitable crystallization conditions of membrane proteins from a membrane-like phase in sub-20 nanoliter volumes. This integrated microfluidic chip and the employed mixing strategy address the specific challenges associated with the mixing of fluids of highly different viscosities (here a factor of 30) as well as the non-Newtonian character of the resulting mesophases. The chip requires less than 20 nL of material per condition screened whereas typically on the order of 10 μL or more is needed for a batch preparation in the present screening methods. We validated our approach with the successful crystallization of the membrane protein bacteriorhodopsin.
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Affiliation(s)
- Sarah L. Perry
- Department of Chemical & Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
| | - Griffin W. Roberts
- Department of Chemical & Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
| | - Joshua D. Tice
- Department of Chemical & Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
| | - Robert B. Gennis
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
| | - Paul J. A. Kenis
- Department of Chemical & Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
- Department of Chemical & Biomolecular Engineering, University of Illinois at Urbana-Champaign, Address: 600 S. Mathews Ave., Urbana, IL 61801, Phone: (217) 265-0523, Fax: (217) 333-5052, , Web Address: http://www.scs.uiuc.edu/~pkgroup/
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33
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Mohammady SZ, Pouzot M, Mezzenga R. Oleoylethanolamide-based lyotropic liquid crystals as vehicles for delivery of amino acids in aqueous environment. Biophys J 2009; 96:1537-46. [PMID: 19217870 DOI: 10.1016/j.bpj.2008.10.057] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2008] [Accepted: 10/08/2008] [Indexed: 11/28/2022] Open
Abstract
We have investigated the phase behavior of self-assembled lyotropic liquid crystals (LC) formed by ternary mixtures of oleoylethanolamide (OEA), water and arginine. OEA, a natural analog of the endogenous cannabinoid anandamide involved in the peripheral regulation of feeding, was selected as a main component due to its capacity to induce efficient decreases in food intake and gains in body mass. Arginine was selected as representative hydrophilic amino acid and added to the OEA-water mixture at different concentrations. The phase diagrams were determined by combining cross-polarized optical microscopy and small angle x-ray scattering. First, the phase diagram for the OEA-water system was determined. It was shown that these two compounds give rise to reverse Ia3d double gyroid and reverse Pn3m double diamond cubic phases existing in bulk over a large window of temperature and composition, and that for water content beyond 25% Pn3m coexisted with excess water. Successively, the influence of arginine as guest molecule in the water channels of the reverse LC was investigated. For the sake of comparison, results for the OEA-water-arginine system were compared with analog series of OEA-water-glucose. The results showed that, at a fixed water content and temperature, the phase behavior of the liquid crystalline phases is strongly dependent on arginine concentration. In more detail, arginine could be encapsulated in the bulk OEA-water LC up to 2.0% wt, whereas transitions from Ia3d to Pn3m cubic phase were observed with increasing arginine concentration. Interestingly, upon an increase of water concentration beyond 20-25%, Pn3m phase started to coexist with excess water releasing the arginine in external water solution. Quantitative measurements of arginine content inside the LC water channels and in the excess external water solution revealed a complete release of the amino acid, demonstrating that the investigated lyotropic liquid crystalline systems can be used as ideal vehicles for the delivery of functional hydrophilic active molecules in aqueous environment.
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Affiliation(s)
- Sayed Z Mohammady
- Department of Chemistry, Faculty of Science, Cairo University, Giza, Egypt
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34
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Amar-Yuli I, Libster D, Aserin A, Garti N. Solubilization of food bioactives within lyotropic liquid crystalline mesophases. Curr Opin Colloid Interface Sci 2009. [DOI: 10.1016/j.cocis.2008.02.001] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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35
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Gruner SM. Commentary: Liposomes or Lipid Science? J Liposome Res 2008. [DOI: 10.3109/08982109909044488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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36
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Yamashita J, Shiono M, Hato M. New Lipid Family That Forms Inverted Cubic Phases in Equilibrium with Excess Water: Molecular Structure−Aqueous Phase Structure Relationship for Lipids with 5,9,13,17-Tetramethyloctadecyl and 5,9,13,17-Tetramethyloctadecanoyl Chains. J Phys Chem B 2008; 112:12286-96. [DOI: 10.1021/jp8029874] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jun Yamashita
- Nanotechnology Research Institute, AIST, Tsukuba Central-5, Higashi 1-1-1, Tsukuba, Ibaraki 305-8565, Japan, and New Business Development Division, Kuraray Company, Ltd. 1-1-3, Otemachi, Chiyoda-ku, Tokyo 100-8115, Japan
| | - Manzo Shiono
- Nanotechnology Research Institute, AIST, Tsukuba Central-5, Higashi 1-1-1, Tsukuba, Ibaraki 305-8565, Japan, and New Business Development Division, Kuraray Company, Ltd. 1-1-3, Otemachi, Chiyoda-ku, Tokyo 100-8115, Japan
| | - Masakatsu Hato
- Nanotechnology Research Institute, AIST, Tsukuba Central-5, Higashi 1-1-1, Tsukuba, Ibaraki 305-8565, Japan, and New Business Development Division, Kuraray Company, Ltd. 1-1-3, Otemachi, Chiyoda-ku, Tokyo 100-8115, Japan
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37
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Abstract
![]()
The objective of molecular electron microscopy (EM) is to use electron
microscopes to visualize the structure of biological molecules. This
Review provides a brief overview of the methods used in molecular
EM, their respective strengths and successes, and current developments
that promise an even more exciting future for molecular EM in the
structural investigation of proteins and macromolecular complexes,
studied in isolation or in the context of cells and tissues.
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Affiliation(s)
- Henning Stahlberg
- Molecular and Cellular Biology,
College of Biological Sciences, University of California at Davis,
Briggs Hall, 1 Shields Avenue, Davis, California 95616
| | - Thomas Walz
- Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, Massachusetts 02115
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38
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A plate holder for non-destructive testing of mesophase crystallization assays. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2008; 37:871-7. [DOI: 10.1007/s00249-008-0296-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2007] [Revised: 02/12/2008] [Accepted: 02/26/2008] [Indexed: 10/22/2022]
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39
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Hite RK, Gonen T, Harrison SC, Walz T. Interactions of lipids with aquaporin-0 and other membrane proteins. Pflugers Arch 2007; 456:651-61. [PMID: 17932686 DOI: 10.1007/s00424-007-0353-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2007] [Accepted: 09/09/2007] [Indexed: 02/08/2023]
Abstract
The structure of aquaporin-0 (AQP0) has recently been determined by electron crystallography of two-dimensional (2D) crystals and by X-ray crystallography of three-dimensional (3D) crystals. The electron crystallographic structure revealed nine lipids per AQP0 monomer, which form an almost complete bilayer. The lipids adopt a wide variety of conformations and tightly fill the space between adjacent AQP0 tetramers. The conformations of the lipid acyl chains appear to be determined not only by the protein surface but also by the acyl chains of adjacent lipid molecules. In the X-ray structure, the hydrophobic region of the protein is surrounded by a detergent micelle, with two ordered detergent molecules per AQP0 monomer. Despite the different environments, the electron crystallographic and X-ray structures of AQP0 are virtually identical, but they differ in the temperature factors of the atoms that either contact the lipids in the 2D crystals or are exposed to detergents in the 3D crystals. The temperature factors are higher in the X-ray structure, suggesting that the detergent-exposed AQP0 residues are less ordered than the corresponding ones contacting lipids in the 2D crystals. An examination of ordered detergent molecules in crystal structures of other aquaporins and of lipid molecules in 2D and 3D crystals of bacteriorhodopsin suggests that the increased conformational variability of detergent-exposed residues compared to lipid-contacting residues is a general feature.
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Affiliation(s)
- Richard K Hite
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
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40
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Nazaruk E, Bilewicz R. Catalytic activity of oxidases hosted in lipidic cubic phases on electrodes. Bioelectrochemistry 2007; 71:8-14. [PMID: 17289444 DOI: 10.1016/j.bioelechem.2006.12.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2006] [Revised: 11/01/2006] [Accepted: 12/29/2006] [Indexed: 11/24/2022]
Abstract
The monoolein-based liquid crystalline cubic phase was used as the matrix to incorporate redox enzymes--glucose (GOx), pyranose (PyOx) oxidases and laccase. Thin layer of the cubic phase embedding GOx or PyOx activated glucose oxidation in the presence and absence of appropriate mediators. The electrodes exhibited unchanged voltammetric response to glucose for not less than six days. The potentials and ratio of catalytic to diffusion currents could be modified by choosing appropriate electroactive probes as mediators. Ferrocenecarboxylic acid and Ru(NH3)6(2+) provided contact between the electrode and the enzyme. The sensitivity to glucose for glucose oxidase was 0.4+/-0.05, 11+/-3.1 microA/cm2/mM without mediator and with ferrocenecarboxylic acid respectively and 0.9+/-0.06, 31+/-5.6 microA/cm2/mM for pyranose oxidase without and with mediator. The system based on glucose oxidase and Ru(NH3)6(2+) as mediator was found useful due to the most negative potential of the process. The catalyses of oxygen reduction by two laccases: Cerrena unicolor and Trametes hirsuta embedded in the cubic phase together with 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonate (ABTS) as the mediator were found efficient and the reduction potential was positive enough to be considered in the application of lyotropic liquid crystals as a material for biofuel cells.
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Affiliation(s)
- Ewa Nazaruk
- Faculty of Chemistry, Warsaw University, Pasteura 1, 02-093 Warsaw, Poland
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41
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Kraineva J, Smirnovas V, Winter R. Effects of lipid confinement on insulin stability and amyloid formation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:7118-26. [PMID: 17523690 DOI: 10.1021/la700405y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
We report on a study of insulin incorporation into cubic phases of mono-olein (MO), using synchrotron small-angle X-ray scattering and FT-IR spectroscopy. We studied the thermal stability and aggregation scenario of insulin as a function of protein concentration in the narrow water channels of the cubic lipid matrix and compared it with data for insulin unfolding and fibrillation in bulk water solutions. The concomitant effect of insulin entrapment on the structure and phase behavior of the lipid matrix itself was also examined. We show that the protein's unfolding behavior and stability are influenced by confinement due to geometrical limitations, and vice versa, the topological properties of the lipid matrix change as well. The addition of insulin already at concentrations as low as 0.1 wt % significantly alters the phase behavior of MO. Surprisingly, new cubic structures are induced by insulin incorporation into the lipid matrix. When insulin begins to partially unfold at higher temperatures, the structure of the new cubic phase changes and finally disappears around 60 degrees C, where the aggregation process sets in. The aggregation in cubo proceeds much faster and leads to the formation of medium-sized oligomers or clusters, while the formation of large fibrillar agglomerates, as observed for bulk insulin aggregation, is largely prohibited. Hence, the results yield valuable information about the use of cubic mesoporous lipid systems as a medium for long-term storage of insulin and aggregation-prone proteins in general. Furthermore, the results provide new insights into the effects of soft-matter confinement on protein aggregation and fibrillation, a situation usually met in natural cell environments.
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Affiliation(s)
- Julia Kraineva
- Department of Chemistry, Physical Chemistry I-Biophysical Chemistry, University of Dortmund, Otto-Hahn Strasse 6, D-44227 Dortmund, Germany
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42
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Carlsson N, Winge AS, Engström S, Akerman B. Diamond cubic phase of monoolein and water as an amphiphilic matrix for electrophoresis of oligonucleotides. J Phys Chem B 2007; 109:18628-36. [PMID: 16853397 DOI: 10.1021/jp0516893] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We used a cubic liquid crystal formed by the nonionic monoglyceride monoolein and water as a porous matrix for the electrophoresis of oligonucleotides. The diamond cubic phase is thermodynamically stable when in contact with a water-rich phase, which we exploit to run the electrophoresis in the useful submarine mode. Oligonucleotides are separated according to size and secondary structure by migration through the space-filling aqueous nanometer pores of the regular liquid crystal, but the comparatively slow migration means the cubic phase will not be a replacement for the conventional DNA gels. However, our demonstration that the cubic phase can be used in submarine electrophoresis opens up the possibility for a new matrix for electrophoresis of amphiphilic molecules. From this perspective, the results on the oligonucleotides show that water-soluble particles of nanometer size, typical for the hydrophilic parts of membrane-bound proteins, may be a useful separation motif. A charged contamination in the commercial sample of monoolein, most likely oleic acid that arises from its hydrolysis, restricts useful buffer conditions to a pH below 5.6.
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Affiliation(s)
- Nils Carlsson
- Department of Chemistry and Bioscience, Chalmers University of Technology, S412 96 Göteborg, Sweden
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43
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Yaghmur A, Laggner P, Zhang S, Rappolt M. Tuning curvature and stability of monoolein bilayers by designer lipid-like peptide surfactants. PLoS One 2007; 2:e479. [PMID: 17534429 PMCID: PMC1868779 DOI: 10.1371/journal.pone.0000479] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2007] [Accepted: 05/03/2007] [Indexed: 11/19/2022] Open
Abstract
This study reports the effect of loading four different charged designer lipid-like short anionic and cationic peptide surfactants on the fully hydrated monoolein (MO)-based Pn3m phase (Q(224)). The studied peptide surfactants comprise seven amino acid residues, namely A(6)D, DA(6), A(6)K, and KA(6). D (aspartic acid) bears two negative charges, K (lysine) bears one positive charge, and A (alanine) constitutes the hydrophobic tail. To elucidate the impact of these peptide surfactants, the ternary MO/peptide/water system has been investigated using small-angle X-ray scattering (SAXS), within a certain range of peptide concentrations (R
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Affiliation(s)
- Anan Yaghmur
- Institute of Biophysics and Nanosystems Research (IBN), Austrian Academy of Sciences, Graz, Austria.
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44
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Abstract
Although the examination of the protein data bank reveals an important backlog in the number of three-dimensional structures of membrane proteins, several recent successes are serving as preludes to what will become a very prosperous decade in this field. Systematic investigations of various factors affecting the stability of membrane proteins, as well as their potential to crystallize three dimensionally, have paved the way for such achievements. The importance of the role of detergents both at the level of purification and crystallization is now well established. In addition, the recognition of the protein-detergent complex as the entity to crystallize, as well as the understanding of its physical-chemical properties and discovery of factors affecting these, have permitted the design of better crystallization strategies. As a consequence of the various efforts in the field, new crystallization methods for membrane proteins are being implemented. These have already been successful and are expected to contribute significantly to the future successes. This chapter will review some basic principles in membrane protein crystallization and give an overview of the current state of the art in the field. Some practical guidelines to help the novice approach the problem of membrane protein crystallization from the initial step of protein purification to crystallogenesis will also be given.
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Affiliation(s)
- James Féthière
- European Molecular Biology Laboratory, Heidelberg, Germany
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45
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Stolarczyk K, Nazaruk E, Rogalski J, Bilewicz R. Mediatorless catalytic oxygen reduction at boron-doped diamond electrodes. Electrochem commun 2007. [DOI: 10.1016/j.elecom.2006.08.044] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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46
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Sanandaji N, Carlsson N, Voinova M, Akerman B. Comparison of oligonucleotide migration in a bicontinuous cubic phase of monoolein and water and in a fibrous agarose hydrogel. Electrophoresis 2006; 27:3007-17. [PMID: 16807936 DOI: 10.1002/elps.200500812] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Porous hydrogels such as agarose are commonly used to analyze DNA and water-soluble proteins by electrophoresis. More recently lyotropic liquid crystals, such as the diamond cubic phase formed by the lipid monoolein and water, has become a new type of well-defined porous structure of interest for both hydrophilic and amphiphilic analytes. Here we compare these two types of matrixes by investigating the nature of retardation they confer to an oligonucleotide that migrates in their respective aqueous phases. The retardation for a 25-mer oligonucleotide was found to be about 35-fold stronger in the cubic phase than in an agarose hydrogel modified to have the same average pore size. According to modelling, the strong retardation is primarily due to the fact that hydrodynamic interaction with the continuous monoolein membrane is a stronger source of friction than the steric interactions (collisions) with discrete gel fibres. A secondary effect is that the regular liquid crystal has a narrower pore-size distribution than the random network of the agarose gel. In agreement with experiments, these two effects together predict that the retardation in the cubic phase is a 30-fold stronger than in an agarose gel with the same average pore radius.
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Affiliation(s)
- Nima Sanandaji
- Department of Chemistry and Bioscience, Chalmers University of Technology, S-41296 Göteborg, Sweden
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47
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Nazaruk E, Michota A, Bukowska J, Shleev S, Gorton L, Bilewicz R. Properties of native and hydrophobic laccases immobilized in the liquid-crystalline cubic phase on electrodes. J Biol Inorg Chem 2006; 12:335-44. [PMID: 17151864 DOI: 10.1007/s00775-006-0193-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2006] [Accepted: 10/24/2006] [Indexed: 12/01/2022]
Abstract
Both native Trametes hirsuta laccase and the same laccase modified with palmytic chains to turn it more hydrophobic were prepared and studied with cyclic voltammetry and Raman spectroscopy. Native laccase immobilized in the monoolein cubic phase was characterized with resonance Raman spectroscopy, which demonstrated that the structure at the "blue" copper site of the protein remained intact. The diamond-type monoolein cubic phase prevents denaturation of enzymes on the electrode surface and provides contact of the enzyme with the electrode either directly or through the mediation by electroactive probes. Direct electron transfer for both laccases incorporated into a lyotropic liquid crystal was obtained under anaerobic conditions, whereas bioelectrocatalytic activity was shown only for the native enzyme. The differences in electrochemical behavior of native and hydrophobic laccase as well as possible mechanisms of direct and mediated electron transfers are discussed. The Michaelis constant for 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) diammonium salt (ABTS2-), KMapp, and the maximal current, Imax, for the native enzyme immobilized onto the electrode were estimated to be 0.24 mM, and 5.3 microA, respectively. The maximal current density and the efficiency of the catalysis, Imax/KMapp, were found to be 73 microA cm-2 and 208.2 microA cm-2 mM-1, respectively, and indicated a high efficiency of oxygen electroreduction by the enzyme in the presence of ABTS2- in the cubic-phase environment. Rate constants were calculated to be 7.5x10(4) and 3.6x10(4) M-1 s-1 for native and hydrophobic laccase, respectively.
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Affiliation(s)
- Ewa Nazaruk
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093, Warsaw, Poland
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48
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Lanyi JK, Schobert B. Structural changes in the L photointermediate of bacteriorhodopsin. J Mol Biol 2006; 365:1379-92. [PMID: 17141271 PMCID: PMC1851893 DOI: 10.1016/j.jmb.2006.11.016] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2006] [Revised: 10/27/2006] [Accepted: 11/03/2006] [Indexed: 11/25/2022]
Abstract
The L to M reaction of the bacteriorhodopsin photocycle includes the crucial proton transfer from the retinal Schiff base to Asp85. In spite of the importance of the L state in deciding central issues of the transport mechanism in this pump, the serious disagreements among the three published crystallographic structures of L have remained unresolved. Here, we report on the X-ray diffraction structure of the L state, to 1.53-1.73 A resolutions, from replicate data sets collected from six independent crystals. Unlike earlier studies, the partial occupancy refinement uses diffraction intensities from the same crystals before and after the illumination to produce the trapped L state. The high reproducibility of inter-atomic distances, and bond angles and torsions of the retinal, lends credibility to the structural model. The photoisomerized 13-cis retinal in L is twisted at the C(13)=C(14) and C(15)=NZ double-bonds, and the Schiff base does not lose its connection to Wat402 and, therefore, to the proton acceptor Asp85. The protonation of Asp85 by the Schiff base in the L-->M reaction is likely to occur, therefore, via Wat402. It is evident from the structure of the L state that various conformational changes involving hydrogen-bonding residues and bound water molecules begin to propagate from the retinal to the protein at this stage already, and in both extracellular and cytoplasmic directions. Their rationales in the transport can be deduced from the way their amplitudes increase in the intermediates that follow L in the reaction cycle, and from the proton transfer reactions with which they are associated.
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Affiliation(s)
- Janos K Lanyi
- Department of Physiology & Biophysics, University of California, Irvine, CA 92697, USA.
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49
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Lanyi JK, Schobert B. Propagating structural perturbation inside bacteriorhodopsin: crystal structures of the M state and the D96A and T46V mutants. Biochemistry 2006; 45:12003-10. [PMID: 17002299 PMCID: PMC2782524 DOI: 10.1021/bi061310i] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The X-ray diffraction structure of the non-illuminated D96A bacteriorhodopsin mutant reveals structural changes as far away as 15 A from residue 96, at the retinal, Trp-182, Ala-215, and waters 501, 402, and 401. The Asp-to-Ala side-chain replacement breaks its hydrogen bond with Thr-46, and the resulting separation of the cytoplasmic ends of helices B and C is communicated to the retinal region through a chain of covalent and hydrogen bonds. The unexpected long-range consequences of the D96A mutation include breaking the hydrogen bond between O of Ala-215 and water 501 and the formation of a new hydrogen bond between water molecules 401 and 402 in the extracellular region. Because in the T46V mutant a new water molecule appears at Asp-96 and its hydrogen-bond to Ile-45 replaces Thr-46 as its link to helix B, the separation of helices B and C is smaller than that in D96A, and there are no atomic displacements elsewhere in the protein. Propagation of conformational changes along the chain between the retinal and Thr-46 had been observed earlier in the crystal structures of the D96N and E204Q mutants but in the trapped M state. Consistent with the perturbation of the retinal region in D96A, little change of the Thr-46 region occurs between the non-illuminated and M states of this mutant. It appears that a local perturbation can propagate along a track in both directions between the retinal and the Asp-96/Thr-46 pair, either from photoisomerization of the retinal in the wild-type protein in one case or from the D96A mutation in the other.
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Affiliation(s)
- Janos K Lanyi
- Department of Physiology and Biophysics, University of California, Irvine, California 92697, USA.
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50
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Kim J, Lu W, Qiu W, Wang L, Caffrey M, Zhong D. Ultrafast Hydration Dynamics in the Lipidic Cubic Phase: Discrete Water Structures in Nanochannels. J Phys Chem B 2006; 110:21994-2000. [PMID: 17064169 DOI: 10.1021/jp062806c] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report here our studies of hydration dynamics of confined water in aqueous nanochannels (approximately 50 A) of the lipidic cubic phase. By systematically anchoring the hydrocarbon tails of a series of tryptophan-alkyl ester probes into the lipid bilayer, we mapped out with femtosecond resolution the profile of water motions across the nanochannel. Three distinct time scales were observed, revealing discrete channel water structures. The interfacial water at the lipid surface is well-ordered, and the relaxation dynamics occurs in approximately 100-150 ps. These dynamically rigid water molecules are crucial for global structural stability of lipid bilayers and for stabilization of anchored biomolecules in membranes. The adjacent water layers near the lipid interface are hydrogen-bonded networks and the dynamical relaxation takes 10-15 ps. This quasi-bound water motion, similar to the typical protein surface hydration relaxation, facilitates conformation flexibility for biological recognition and function. The water near the channel center is bulklike, and the dynamics is ultrafast in less than 1 ps. These water molecules freely transport biomolecules near the channel center. The corresponding orientational relaxation at these three typical locations is well correlated with the hydration dynamics and local dynamic rigidity. These results reveal unique water structures and dynamical motions in nanoconfinements, which is critical to the understanding of nanoscopic biological activities and nanomaterial properties.
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Affiliation(s)
- Jongjoo Kim
- Department of Physics, Program of Biophysics, The Ohio State University, Columbus, Ohio 43210, USA
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