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Ortiz-Soto ME, Baier M, Brenner D, Timm M, Seibel J. Single-mutations at the galactose-binding site of enzymes GalK, GalU, and LgtC enable the efficient synthesis of UDP-6-azido-6-deoxy-d-galactose and azido-functionalized Gb3 analogs. Glycobiology 2023; 33:651-660. [PMID: 37283491 DOI: 10.1093/glycob/cwad045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 06/05/2023] [Accepted: 06/05/2023] [Indexed: 06/08/2023] Open
Abstract
Lysosomal accumulation of the glycosphingolipid globotriaosylceramide Gb3 is linked to the deficient activity of the α-galactosidase A in the Anderson-Fabry disease and an elevated level of deacylated Gb3 is a hallmark of this condition. Localization of Gb3 in the plasma membrane is critical for studying how the membrane organization and its dynamics are affected in this genetic disorder. Gb3 analogs containing a terminal 6-azido-functionalized galactose in its head group globotriose (αGal1, 4βGal1, and 4Glc) are attractive chemical reporters for bioimaging, as the azido-group may act as a chemical tag for bio-orthogonal click chemistry. We report here the production of azido-Gb3 analogs employing mutants of galactokinase, UTP-glucose-1-phosphate uridylyltransferase, and α-1,4-galactosyltransferase LgtC, which participate in the synthesis of the sugar motif globotriose. Variants of enzymes galactokinase/UTP-glucose-1-phosphate uridylyltransferase generate UDP-6-azido-6-deoxy-d-galactose, which is the galactosyl-donor used by LgtC for transferring the terminal galactose moiety to lactosyl-acceptors. Residues at the galactose-binding site of the 3 enzymes were modified to facilitate the accommodation of azido-functionalized substrates and variants outperforming the wild-type enzymes were characterized. Synthesis of 6-azido-6-deoxy-d-galactose-1-phosphate, UDP-6-azido-6-deoxy-d-galactose, and azido-Gb3 analogs by variants GalK-E37S, GalU-D133V, and LgtC-Q187S, respectively, is 3-6-fold that of their wild-type counterparts. Coupled reactions with these variants permit the production of the pricy, unnatural galactosyl-donor UDP-6-azido-6-deoxy-d-galactose with ~90% conversion yields, and products azido-globotriose and lyso-AzGb3 with substrate conversion of up to 70%. AzGb3 analogs could serve as precursors for the synthesis of other tagged glycosphingolipids of the globo-series.
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Affiliation(s)
- Maria E Ortiz-Soto
- Institut für Organische Chemie, Julius-Maximilians-Universität, Am Hubland, 97074 Würzburg, Germany
| | - Makarius Baier
- Institut für Organische Chemie, Julius-Maximilians-Universität, Am Hubland, 97074 Würzburg, Germany
| | - Daniela Brenner
- Institut für Organische Chemie, Julius-Maximilians-Universität, Am Hubland, 97074 Würzburg, Germany
| | - Malte Timm
- Institut für Organische Chemie, Julius-Maximilians-Universität, Am Hubland, 97074 Würzburg, Germany
| | - Jürgen Seibel
- Institut für Organische Chemie, Julius-Maximilians-Universität, Am Hubland, 97074 Würzburg, Germany
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2
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Socrier L, Ahadi S, Bosse M, Montag C, Werz DB, Steinem C. Optical Manipulation of Gb 3 Enriched Lipid Domains: Impact of Isomerization on Gb 3 -Shiga Toxin B Interaction. Chemistry 2023; 29:e202202766. [PMID: 36279320 PMCID: PMC10099549 DOI: 10.1002/chem.202202766] [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: 09/05/2022] [Indexed: 11/06/2022]
Abstract
The plasma membrane is a complex assembly of proteins and lipids that can self-assemble in submicroscopic domains commonly termed "lipid rafts", which are implicated in membrane signaling and trafficking. Recently, photo-sensitive lipids were introduced to study membrane domain organization, and photo-isomerization was shown to trigger the mixing and de-mixing of liquid-ordered (lo ) domains in artificial phase-separated membranes. Here, we synthesized globotriaosylceramide (Gb3 ) glycosphingolipids that harbor an azobenzene moiety at different positions of the fatty acid to investigate light-induced membrane domain reorganization, and that serve as specific receptors for the protein Shiga toxin (STx). Using phase-separated supported lipid bilayers on mica surfaces doped with four different photo-Gb3 molecules, we found by fluorescence microscopy and atomic force microscopy that liquid disordered (ld ) domains were formed within lo domains upon trans-cis photo-isomerization. The fraction and size of these ld domains were largest for Gb3 molecules with the azobenzene group at the end of the fatty acid. We further investigated the impact of domain reorganization on the interaction of the B-subunits of STx with the photo-Gb3 . Fluorescence and atomic force micrographs clearly demonstrated that STxB binds to the lo phase if Gb3 is in the trans-configuration, whereas two STxB populations are formed if the photo-Gb3 is switched to the cis-configuration highlighting the idea of manipulating lipid-protein interactions with a light stimulus.
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Affiliation(s)
- Larissa Socrier
- Max Planck Institute for Dynamics and Self-Organization, Am Faßberg 17, 37077, Göttingen, Germany.,Institute of Organic and Biomolecular Chemistry, Georg-August-Universität, Tammannstraße 2, 37077, Göttingen, Germany
| | - Somayeh Ahadi
- Institute of Organic Chemistry, Technische Universität Braunschweig, Hagenring 30, 38106, Braunschweig, Germany
| | - Mathias Bosse
- Institute for Medical Physics and Biophysics, University of Leipzig, Härtelstraße 16-18, 04107, Leipzig, Germany
| | - Cindy Montag
- Institute for Medical Physics and Biophysics, University of Leipzig, Härtelstraße 16-18, 04107, Leipzig, Germany
| | - Daniel B Werz
- Institute of Organic Chemistry, Technische Universität Braunschweig, Hagenring 30, 38106, Braunschweig, Germany.,Institute of Organic Chemistry, Albert-Ludwigs-Universität Freiburg, Albertstraße 21, 79104, Freiburg, Germany
| | - Claudia Steinem
- Max Planck Institute for Dynamics and Self-Organization, Am Faßberg 17, 37077, Göttingen, Germany.,Institute of Organic and Biomolecular Chemistry, Georg-August-Universität, Tammannstraße 2, 37077, Göttingen, Germany
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3
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Socrier L, Bail C, Ackermann E, Beresowski AK, Ahadi S, Werz DB, Steinem C. The Interaction of Gb 3 Glycosphingolipids with ld and lo Phase Lipids in Lipid Monolayers Is a Function of Their Fatty Acids. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:5874-5882. [PMID: 35439015 DOI: 10.1021/acs.langmuir.2c00497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The glycosphingolipid Gb3 is a specific receptor of the bacterial Shiga toxin (STx). Binding of STx to Gb3 is a prerequisite for its internalization into the host cells, and the ceramide's fatty acid of Gb3 has been shown to influence STx binding. In in vitro studies on liquid ordered (lo)/liquid disordered (ld) coexisting artificial membranes, Shiga toxin B (STxB) binds solely to lo domains, thus harboring Gb3 concomitant with an observed lipid redistribution process. These findings raise the question of how the molecular structure of the fatty acid of Gb3 influences the interaction of Gb3 with the different lipids preferentially either found in the lo phase, namely, sphingomyelin and cholesterol, or in the ld phase. We addressed this question by using a series of synthetically available and unlabeled Gb3 glycosphingolipids carrying different long chain C24 fatty acids (saturated, monounsaturated, and α-hydroxylated). In conjunction with surface tension experiments on Langmuir monolayers, we quantified the excess of free energy of mixing of the different Gb3 species in monolayers composed of either sphingomyelin or cholesterol or composed of a fluid phase lipid (DOPC). From a calculation of the total free energy of mixing, we conclude that mixing of the saturated Gb3 species with the ld lipid DOPC is energetically less favorable than all other combinations, while the unsaturated species mix equally well with the lo phase lipids sphingomyelin and cholesterol and the ld phase lipid DOPC. Furthermore, we found that STxB partially penetrates in mixed lipid monolayers (DOPC/sphingomyelin/cholesterol) containing the Gb3 sphingolipid with a saturated or a monounsaturated C24 fatty acid. The maximum insertion pressure, as a measure for protein insertion, is >30 mN/m for both Gb3 molecules and is not significantly different for the two Gb3 species.
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Affiliation(s)
- Larissa Socrier
- Max-Planck-Institute for Dynamics and Self-Organization, Am Fassberg 17, 37077 Göttingen, Germany
- Institute of Organic and Biomolecular Chemistry, Georg-August-Universität, Tammannstraße 2, 37077 Göttingen, Germany
| | - Céline Bail
- Institute of Organic and Biomolecular Chemistry, Georg-August-Universität, Tammannstraße 2, 37077 Göttingen, Germany
| | - Elena Ackermann
- Institute of Organic and Biomolecular Chemistry, Georg-August-Universität, Tammannstraße 2, 37077 Göttingen, Germany
| | - Ann-Kathrin Beresowski
- Institute of Organic and Biomolecular Chemistry, Georg-August-Universität, Tammannstraße 2, 37077 Göttingen, Germany
| | - Somayeh Ahadi
- Institute of Organic Chemistry, Technische Universität Braunschweig, Hagenring 30, 38106 Braunschweig, Germany
| | - Daniel B Werz
- Institute of Organic Chemistry, Technische Universität Braunschweig, Hagenring 30, 38106 Braunschweig, Germany
| | - Claudia Steinem
- Max-Planck-Institute for Dynamics and Self-Organization, Am Fassberg 17, 37077 Göttingen, Germany
- Institute of Organic and Biomolecular Chemistry, Georg-August-Universität, Tammannstraße 2, 37077 Göttingen, Germany
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4
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Sych T, Gurdap CO, Wedemann L, Sezgin E. How Does Liquid-Liquid Phase Separation in Model Membranes Reflect Cell Membrane Heterogeneity? MEMBRANES 2021; 11:323. [PMID: 33925240 PMCID: PMC8146956 DOI: 10.3390/membranes11050323] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 04/22/2021] [Accepted: 04/26/2021] [Indexed: 11/22/2022]
Abstract
Although liquid-liquid phase separation of cytoplasmic or nuclear components in cells has been a major focus in cell biology, it is only recently that the principle of phase separation has been a long-standing concept and extensively studied in biomembranes. Membrane phase separation has been reconstituted in simplified model systems, and its detailed physicochemical principles, including essential phase diagrams, have been extensively explored. These model membrane systems have proven very useful to study the heterogeneity in cellular membranes, however, concerns have been raised about how reliably they can represent native membranes. In this review, we will discuss how phase-separated membrane systems can mimic cellular membranes and where they fail to reflect the native cell membrane heterogeneity. We also include a few humble suggestions on which phase-separated systems should be used for certain applications, and which interpretations should be avoided to prevent unreliable conclusions.
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Affiliation(s)
| | | | | | - Erdinc Sezgin
- Science for Life Laboratory, Department of Women’s and Children’s Health, Karolinska Institutet, 17165 Solna, Sweden; (T.S.); (C.O.G.); (L.W.)
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5
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Patalag LJ, Ahadi S, Lashchuk O, Jones PG, Ebbinghaus S, Werz DB. GlycoBODIPYs: Sugars Serving as a Natural Stock for Water‐soluble Fluorescent Probes of Complex Chiral Morphology. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202016764] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Lukas J. Patalag
- TU Braunschweig Institute of Organic Chemistry Hagenring 30 38106 Braunschweig Germany
| | - Somayeh Ahadi
- TU Braunschweig Institute of Organic Chemistry Hagenring 30 38106 Braunschweig Germany
| | - Olesia Lashchuk
- TU Braunschweig Institute of Physical and Theoretical Chemistry, and Braunschweig Integrated Centre of Systems Biology Rebenring 56 38106 Braunschweig Germany
| | - Peter G. Jones
- TU Braunschweig Institute of Inorganic and Analytical Chemistry Hagenring 30 38106 Braunschweig Germany
| | - Simon Ebbinghaus
- TU Braunschweig Institute of Physical and Theoretical Chemistry, and Braunschweig Integrated Centre of Systems Biology Rebenring 56 38106 Braunschweig Germany
| | - Daniel B. Werz
- TU Braunschweig Institute of Organic Chemistry Hagenring 30 38106 Braunschweig Germany
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6
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Patalag LJ, Ahadi S, Lashchuk O, Jones PG, Ebbinghaus S, Werz DB. GlycoBODIPYs: Sugars Serving as a Natural Stock for Water-soluble Fluorescent Probes of Complex Chiral Morphology. Angew Chem Int Ed Engl 2021; 60:8766-8771. [PMID: 33492705 PMCID: PMC8048574 DOI: 10.1002/anie.202016764] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/11/2021] [Indexed: 12/31/2022]
Abstract
A range of unprocessed, reducing sugar substrates (mono-, di-, and trisaccharides) is shown to take part in a straightforward four-step synthetic route to water-soluble, uncharged BODIPY derivatives with unimpaired chiral integrity and high fluorescence efficiency. A wide compatibility with several postfunctionalizations is demonstrated, thus suggesting a universal utility of the multifunctional glycoconjugates, which we call GlycoBODIPYs. Knoevenagel condensations are able to promote a red-shift in the spectra, thereby furnishing strongly fluorescent red and far-red glycoconjugates of high hydrophilicity. The synthetic outcome was studied by X-ray crystallography and by comprehensive photophysical investigations in several solvent systems. Furthermore, cell experiments illustrate efficient cell uptake and demonstrate differential cell targeting as a function of the integrated chiral information.
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Affiliation(s)
- Lukas J. Patalag
- TU BraunschweigInstitute of Organic ChemistryHagenring 3038106BraunschweigGermany
| | - Somayeh Ahadi
- TU BraunschweigInstitute of Organic ChemistryHagenring 3038106BraunschweigGermany
| | - Olesia Lashchuk
- TU BraunschweigInstitute of Physical and Theoretical Chemistry, and Braunschweig Integrated Centre of Systems BiologyRebenring 5638106BraunschweigGermany
| | - Peter G. Jones
- TU BraunschweigInstitute of Inorganic and Analytical ChemistryHagenring 3038106BraunschweigGermany
| | - Simon Ebbinghaus
- TU BraunschweigInstitute of Physical and Theoretical Chemistry, and Braunschweig Integrated Centre of Systems BiologyRebenring 5638106BraunschweigGermany
| | - Daniel B. Werz
- TU BraunschweigInstitute of Organic ChemistryHagenring 3038106BraunschweigGermany
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7
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Sibold J, Ahadi S, Werz DB, Steinem C. Chemically synthesized Gb 3 glycosphingolipids: tools to access their function in lipid membranes. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2021; 50:109-126. [PMID: 32948883 PMCID: PMC8071800 DOI: 10.1007/s00249-020-01461-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/24/2020] [Accepted: 08/26/2020] [Indexed: 12/19/2022]
Abstract
Gb3 glycosphingolipids are the specific receptors for bacterial Shiga toxin. Whereas the trisaccharidic head group of Gb3 defines the specificity of Shiga toxin binding, the lipophilic part composed of sphingosine and different fatty acids is suggested to determine its localization within membranes impacting membrane organisation and protein binding eventually leading to protein internalisation. While most studies use Gb3 extracts, chemical synthesis provides a unique tool to access different tailor-made Gb3 glycosphingolipids. In this review, strategies to synthesize these complex glycosphingolipids are presented. Special emphasis is put on the preparation of Gb3 molecules differing only in their fatty acid part (saturated, unsaturated, α-hydroxylated and both, unsaturated and α-hydroxylated). With these molecules in hand, it became possible to investigate the phase behaviour of liquid ordered/liquid disordered supported membranes doped with the Gb3 species by means of fluorescence and atomic force microscopy. The results clearly highlight the influence of the different fatty acids of the Gb3 sphingolipids on the phase behaviour and the binding properties of Shiga toxin B subunits, even though the membranes were only doped with 5 mol% of the receptor lipid. To obtain fluorescent Gb3 derivatives, either fatty acid labelled Gb3 molecules or head group labelled ones were synthesized. These molecules enabled us to address the question, where the Gb3 sphingolipids are localized prior protein binding by means of fluorescence microscopy on giant unilamellar vesicles. The results again demonstrate that the fatty acid of Gb3 plays a pivotal role for the overall membrane organisation.
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Affiliation(s)
- Jeremias Sibold
- Georg-August-Universität Göttingen, Institute of Organic and Biomolecular Chemistry, Tammannstr. 2, 37077, Göttingen, Germany
| | - Somayeh Ahadi
- Technische Universität Braunschweig, Institute of Organic Chemistry, Hagenring 30, 38106, Braunschweig, Germany
| | - Daniel B Werz
- Technische Universität Braunschweig, Institute of Organic Chemistry, Hagenring 30, 38106, Braunschweig, Germany.
| | - Claudia Steinem
- Georg-August-Universität Göttingen, Institute of Organic and Biomolecular Chemistry, Tammannstr. 2, 37077, Göttingen, Germany.
- Max Planck Institute for Dynamics and Self Organization, Am Faßberg 17, 37077, Göttingen, Germany.
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8
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Sibold J, Kettelhoit K, Vuong L, Liu F, Werz DB, Steinem C. Synthesis of Gb 3 Glycosphingolipids with Labeled Head Groups: Distribution in Phase-Separated Giant Unilamellar Vesicles. Angew Chem Int Ed Engl 2019; 58:17805-17813. [PMID: 31529754 PMCID: PMC6899692 DOI: 10.1002/anie.201910148] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 09/09/2019] [Indexed: 11/22/2022]
Abstract
The receptor lipid Gb3 is responsible for the specific internalization of Shiga toxin (STx) into cells. The head group of Gb3 defines the specificity of STx binding, and the backbone with different fatty acids is expected to influence its localization within membranes impacting membrane organization and protein internalization. To investigate this influence, a set of Gb3 glycosphingolipids labeled with a BODIPY fluorophore attached to the head group was synthesized. C24 fatty acids, saturated, unsaturated, α-hydroxylated derivatives, and a combination thereof, were attached to the sphingosine backbone. The synthetic Gb3 glycosphingolipids were reconstituted into coexisting liquid-ordered (lo )/liquid-disordered (ld ) giant unilamellar vesicles (GUVs), and STx binding was verified by fluorescence microscopy. Gb3 with the C24:0 fatty acid partitioned mostly in the lo phase, while the unsaturated C24:1 fatty acid distributes more into the ld phase. The α-hydroxylation does not influence its partitioning.
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Affiliation(s)
- Jeremias Sibold
- Georg-August-Universität GöttingenInstitute of Organic and Biomolecular ChemistryTammannstr. 237077GöttingenGermany
| | - Katharina Kettelhoit
- Technische Universität BraunschweigInstitute of Organic ChemistryHagenring 3038106BraunschweigGermany
| | - Loan Vuong
- Georg-August-Universität GöttingenInstitute of Organic and Biomolecular ChemistryTammannstr. 237077GöttingenGermany
| | - Fangyuan Liu
- Georg-August-Universität GöttingenInstitute of Organic and Biomolecular ChemistryTammannstr. 237077GöttingenGermany
| | - Daniel B. Werz
- Technische Universität BraunschweigInstitute of Organic ChemistryHagenring 3038106BraunschweigGermany
| | - Claudia Steinem
- Georg-August-Universität GöttingenInstitute of Organic and Biomolecular ChemistryTammannstr. 237077GöttingenGermany
- Max Planck Institute for Dynamics and Self OrganizationAm Faßberg 1737077GöttingenGermany
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9
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Sibold J, Kettelhoit K, Vuong L, Liu F, Werz DB, Steinem C. Synthesis of Gb
3
Glycosphingolipids with Labeled Head Groups: Distribution in Phase‐Separated Giant Unilamellar Vesicles. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201910148] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Jeremias Sibold
- Georg-August-Universität GöttingenInstitute of Organic and Biomolecular Chemistry Tammannstr. 2 37077 Göttingen Germany
| | - Katharina Kettelhoit
- Technische Universität BraunschweigInstitute of Organic Chemistry Hagenring 30 38106 Braunschweig Germany
| | - Loan Vuong
- Georg-August-Universität GöttingenInstitute of Organic and Biomolecular Chemistry Tammannstr. 2 37077 Göttingen Germany
| | - Fangyuan Liu
- Georg-August-Universität GöttingenInstitute of Organic and Biomolecular Chemistry Tammannstr. 2 37077 Göttingen Germany
| | - Daniel B. Werz
- Technische Universität BraunschweigInstitute of Organic Chemistry Hagenring 30 38106 Braunschweig Germany
| | - Claudia Steinem
- Georg-August-Universität GöttingenInstitute of Organic and Biomolecular Chemistry Tammannstr. 2 37077 Göttingen Germany
- Max Planck Institute for Dynamics and Self Organization Am Faßberg 17 37077 Göttingen Germany
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10
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Bosse M, Sibold J, Scheidt HA, Patalag LJ, Kettelhoit K, Ries A, Werz DB, Steinem C, Huster D. Shiga toxin binding alters lipid packing and the domain structure of Gb 3-containing membranes: a solid-state NMR study. Phys Chem Chem Phys 2019; 21:15630-15638. [PMID: 31268447 DOI: 10.1039/c9cp02501d] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
We studied the influence of globotriaosylceramide (Gb3) lipid molecules on the properties of phospholipid membranes composed of a liquid ordered (lo)/liquid disordered (ld) phase separated 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)/N-palmitoyl-d-erythro-sphingosylphosphorylcholine (PSM)/cholesterol mixture (40/35/20, mol/mol/mol) supplemented with 5 mol% of either short acyl chain palmitoyl-Gb3 or long acyl chain lignoceryl-Gb3 using 2H solid-state NMR spectroscopy. To this end, both globotriaosylceramides were chemically synthesized featuring a perdeuterated lipid acyl chain. The solid-state 2H NMR spectra support the phase separation into a POPC-rich ld phase and a PSM/cholesterol-rich lo phase. The long chain lignoceryl-Gb3 showed a rather unusual order parameter profile of the acyl chain, which flattens out for the last ∼6 methylene segments. Such an odd chain conformation can be explained by partial chain interdigitation and/or a very fluid midplane region of the membrane. Possibly, the Gb3 molecules may thus preferentially be localized at the lo/ld phase boundary. In contrast, the short chain palmitoyl-Gb3 was well associated with the PSM/cholesterol-rich lo phase. Gb3 molecules act as membrane receptors for the Shiga toxin (STx) produced by Shigella dysenteriae and by enterohemorrhagic strains of Escherichia coli (EHEC). The B-subunits of STx (STxB) forming a pentameric structure were produced recombinantly and incubated with the membrane mixtures leading to alterations in the lipid packing properties and lateral organization of the membranes. Typically, STxB binding led to a decrease in lipid chain order in agreement with partial immersion of protein segments into the lipid-water interface of the membrane. In the presence of STxB, Gb3 preferentially partitioned into the lo membrane phase. In particular the short acyl chain palmitoyl-Gb3 showed very similar chain order parameters to PSM. In the presence of STxB, all lipid species showed isotropic contributions to the 2H NMR powder spectra; this was most pronounced for the Gb3 molecules. Such isotropic contributions are caused by highly curved membrane structures, which have previously been detected as membrane invaginations in fluorescence microscopy. Our analysis estimated that STxB induced highly curved membrane structures with a curvature radius of less than ∼10 nm likely related to the insertion of STxB segments into the lipid-water interface of the membrane.
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Affiliation(s)
- Mathias Bosse
- Institute for Medical Physics and Biophysics, Leipzig University, Härtelstr. 16-18, D-04107 Leipzig, Germany.
| | - Jeremias Sibold
- Institute for Organic and Biomolecular Chemistry, University of Göttingen, Tammannstr. 2, D-37077 Göttingen, Germany
| | - Holger A Scheidt
- Institute for Medical Physics and Biophysics, Leipzig University, Härtelstr. 16-18, D-04107 Leipzig, Germany.
| | - Lukas J Patalag
- Technische Universität Braunschweig, Institute of Organic Chemistry, Hagenring 30, D-38106 Braunschweig, Germany
| | - Katharina Kettelhoit
- Technische Universität Braunschweig, Institute of Organic Chemistry, Hagenring 30, D-38106 Braunschweig, Germany
| | - Annika Ries
- Technische Universität Braunschweig, Institute of Organic Chemistry, Hagenring 30, D-38106 Braunschweig, Germany
| | - Daniel B Werz
- Technische Universität Braunschweig, Institute of Organic Chemistry, Hagenring 30, D-38106 Braunschweig, Germany
| | - Claudia Steinem
- Institute for Organic and Biomolecular Chemistry, University of Göttingen, Tammannstr. 2, D-37077 Göttingen, Germany and Max-Planck-Institute for Dynamics and Self-Organization, Am Fassberg 11, 37077 Göttingen, Germany
| | - Daniel Huster
- Institute for Medical Physics and Biophysics, Leipzig University, Härtelstr. 16-18, D-04107 Leipzig, Germany.
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11
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Fink J, Seibel J. Click reactions with functional sphingolipids. Biol Chem 2019; 399:1157-1168. [PMID: 29908120 DOI: 10.1515/hsz-2018-0169] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 04/15/2018] [Indexed: 12/17/2022]
Abstract
Sphingolipids and glycosphingolipids can regulate cell recognition and signalling. Ceramide and sphingosine-1-phosphate are major players in the sphingolipid pathways and are involved in the initiation and regulation of signalling, apoptosis, stress responses and infection. Specific chemically synthesised sphingolipid derivatives containing small functionalities like azide or alkyne can mimic the biological properties of natural lipid species, which turns them into useful tools for the investigation of the highly complex sphingolipid metabolism by rapid and selective 'click chemistry' using sensitive tags like fluorophores. Subsequent analysis by various fluorescence microscopy techniques or mass spectrometry allows the identification and quantification of the corresponding sphingolipid metabolites as well as the research of associated enzymes. Here we present an overview of recent advances in the synthesis of ceramide and sphingosine analogues for bioorthogonal click reactions to study biosynthetic pathways and localization of sphingolipids for the development of novel therapeutics against lipid-dependent diseases.
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Affiliation(s)
- Julian Fink
- University of Würzburg, Institute of Organic Chemistry, Am Hubland, D-97074 Würzburg, Germany
| | - Jürgen Seibel
- University of Würzburg, Institute of Organic Chemistry, Am Hubland, D-97074 Würzburg, Germany
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12
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Hunter CD, Guo T, Daskhan G, Richards MR, Cairo CW. Synthetic Strategies for Modified Glycosphingolipids and Their Design as Probes. Chem Rev 2018; 118:8188-8241. [DOI: 10.1021/acs.chemrev.8b00070] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Carmanah D. Hunter
- Alberta Glycomics Centre, Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Tianlin Guo
- Alberta Glycomics Centre, Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Gour Daskhan
- Alberta Glycomics Centre, Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Michele R. Richards
- Alberta Glycomics Centre, Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Christopher W. Cairo
- Alberta Glycomics Centre, Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
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