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Modzel M, Solanko KA, Szomek M, Hansen SK, Dupont A, Nåbo LJ, Kongsted J, Wüstner D. Live-cell imaging of new polyene sterols for improved analysis of intracellular cholesterol transport. J Microsc 2018. [PMID: 29516493 DOI: 10.1111/jmi.12691] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Analysis of intracellular cholesterol transport by fluorescence microscopy requires suitable fluorescent analogues of cholesterol. Most existing cholesterol analogues contain lipophilic dyes which can compromise the sterol properties in membranes. An alternative strategy is to introduce additional double bonds into the sterol ring system resulting in intrinsic fluorescence, while at the same time keeping the cholesterol-like properties of the analogues. Existing polyene sterols, such as dehydroergosterol (DHE) or cholestatrienol (CTL), however, contain only three double bonds and suffer from low brightness, significant photobleaching and excitation/emission in the ultraviolet region. Thus, special equipment is required to image such sterols. Here, we describe synthesis, characterization and intracellular imaging of new polyene sterols containing four conjugated double bonds in the sterol ring system. We show that such analogues have red-shifted excitation and emission by ∼20 nm compared to DHE or CTL. The red shift was even more pronounced when preventing keto-enol tautomer equilibration by protecting the 3'-hydroxy group with acetate. We show that the latter analogue can be imaged on a conventional wide field microscope with a DAPI/filipin filter cube. The new polyene sterols show reduced photobleaching compared to DHE or CTL allowing for improved deconvolution microscopy of sterol containing cellular membranes.
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Affiliation(s)
- M Modzel
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense, Denmark
| | - K A Solanko
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense, Denmark
| | - M Szomek
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense, Denmark
| | - S K Hansen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense, Denmark
| | - A Dupont
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense, Denmark
| | - L J Nåbo
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, DK-5230 Odense, Denmark
| | - J Kongsted
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, DK-5230 Odense, Denmark
| | - D Wüstner
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense, Denmark
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Nåbo LJ, Olsen JMH, Martínez TJ, Kongsted J. The Quality of the Embedding Potential Is Decisive for Minimal Quantum Region Size in Embedding Calculations: The Case of the Green Fluorescent Protein. J Chem Theory Comput 2017; 13:6230-6236. [DOI: 10.1021/acs.jctc.7b00528] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lina J. Nåbo
- Department
of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - Jógvan Magnus Haugaard Olsen
- Department
of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - Todd J. Martínez
- Department
of Chemistry and PULSE Institute, Stanford University, Stanford, California 94305, United States
- SLAC National Accelerator Laboratory, Menlo Park, California 94305, United States
| | - Jacob Kongsted
- Department
of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
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Pezeshkian W, Nåbo LJ, Ipsen JH. Cholera toxin B subunit induces local curvature on lipid bilayers. FEBS Open Bio 2017; 7:1638-1645. [PMID: 29123973 PMCID: PMC5666388 DOI: 10.1002/2211-5463.12321] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 09/08/2017] [Accepted: 09/19/2017] [Indexed: 12/22/2022] Open
Abstract
The B subunit of the bacterial cholera toxin (CTxB) is responsible for the toxin binding to the cell membrane and its intracellular trafficking. CTxB binds to the monosialotetrahexosyl ganglioside at the plasma membrane of the target cell and mediates toxin internalization by endocytosis. CTxB induces a local membrane curvature that is essential for its clathrin-independent uptake. Using all-atom molecular dynamics, we show that CTxB induces local curvature, with the radius of curvature around 36 nm. The main feature of the CTxB molecular structure that causes membrane bending is the protruding alpha helices in the middle of the protein. Our study points to a generic protein design principle for generating local membrane curvature through specific binding to their lipid anchors.
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Affiliation(s)
- Weria Pezeshkian
- Center for Biomembrane Physics (MEMPHYS) Department of Physics, Chemistry and Pharmacy (FKF) University of Southern Denmark Odense Odense M Denmark
| | - Lina J Nåbo
- Center for Biomembrane Physics (MEMPHYS) Department of Physics, Chemistry and Pharmacy (FKF) University of Southern Denmark Odense Odense M Denmark
| | - John H Ipsen
- Center for Biomembrane Physics (MEMPHYS) Department of Physics, Chemistry and Pharmacy (FKF) University of Southern Denmark Odense Odense M Denmark
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Affiliation(s)
- Lina J. Nåbo
- Department
of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - Nanna Holmgaard List
- Division
of Theoretical Chemistry and Biology, School of Biotechnology, KTH Royal Institute of Technology, SE-106 91 Stockholm, Sweden
| | - Casper Steinmann
- Centre
for Computational Chemistry, School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Jacob Kongsted
- Department
of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
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Nåbo LJ, Olsen JMH, Holmgaard List N, Solanko LM, Wüstner D, Kongsted J. Embedding beyond electrostatics—The role of wave function confinement. J Chem Phys 2016; 145:104102. [DOI: 10.1063/1.4962367] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
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Nåbo LJ, List NH, Witzke S, Wüstner D, Khandelia H, Kongsted J. Design of new fluorescent cholesterol and ergosterol analogs: Insights from theory. Biochimica et Biophysica Acta (BBA) - Biomembranes 2015; 1848:2188-99. [DOI: 10.1016/j.bbamem.2015.04.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 04/24/2015] [Accepted: 04/29/2015] [Indexed: 12/23/2022]
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Nåbo LJ, Madsen CS, Jensen KJ, Kongsted J, Astakhova K. Corrigendum: Ultramild Protein-Mediated Click Chemistry Creates Efficient Oligonucleotide Probes for Targeting and Detecting Nucleic Acids. Chembiochem 2015. [DOI: 10.1002/cbic.201500230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Nåbo LJ, Madsen CS, Jensen KJ, Kongsted J, Astakhova K. Ultramild protein-mediated click chemistry creates efficient oligonucleotide probes for targeting and detecting nucleic acids. Chembiochem 2015; 16:1163-7. [PMID: 25940911 DOI: 10.1002/cbic.201500145] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Indexed: 12/16/2022]
Abstract
Functionalized synthetic oligonucleotides are finding growing applications in research, clinical studies, and therapy. However, it is not easy to prepare them in a biocompatible and highly efficient manner. We report a new strategy to synthesize oligonucleotides with promising nucleic acid targeting and detection properties. We focus in particular on the pH sensitivity of these new probes and their high target specificity. For the first time, human copper(I)-binding chaperon Cox17 was applied to effectively catalyze click labeling of oligonucleotides. This was performed under ultramild conditions with fluorophore, peptide, and carbohydrate azide derivatives. In thermal denaturation studies, the modified probes showed specific binding to complementary DNA and RNA targets. Finally, we demonstrated the pH sensitivity of the new rhodamine-based fluorescent probes in vitro and rationalize our results by electronic structure calculations.
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Affiliation(s)
- Lina J Nåbo
- Department of Physics and Chemistry, University of Southern Denmark, Campusvej 55, 5230 Odense M (Denmark)
| | - Charlotte S Madsen
- Department of Chemistry, University of Copenhagen (Denmark), Thorvaldsensvej 40, 1871 Copenhagen (Denmark)
| | - Knud J Jensen
- Department of Chemistry, University of Copenhagen (Denmark), Thorvaldsensvej 40, 1871 Copenhagen (Denmark)
| | - Jacob Kongsted
- Department of Physics and Chemistry, University of Southern Denmark, Campusvej 55, 5230 Odense M (Denmark)
| | - Kira Astakhova
- Department of Physics and Chemistry, University of Southern Denmark, Campusvej 55, 5230 Odense M (Denmark).
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Eriksen JJ, Solanko LM, Nåbo LJ, Wüstner D, Sauer SP, Kongsted J. The Second-Order Polarization Propagator Approximation (SOPPA) method coupled to the polarizable continuum model. COMPUT THEOR CHEM 2014. [DOI: 10.1016/j.comptc.2014.02.034] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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