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Tincu (Iurciuc) CE, Andrițoiu CV, Popa M, Ochiuz L. Recent Advancements and Strategies for Overcoming the Blood-Brain Barrier Using Albumin-Based Drug Delivery Systems to Treat Brain Cancer, with a Focus on Glioblastoma. Polymers (Basel) 2023; 15:3969. [PMID: 37836018 PMCID: PMC10575401 DOI: 10.3390/polym15193969] [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: 08/14/2023] [Revised: 09/23/2023] [Accepted: 09/26/2023] [Indexed: 10/15/2023] Open
Abstract
Glioblastoma multiforme (GBM) is a highly aggressive malignant tumor, and the most prevalent primary malignant tumor affecting the brain and central nervous system. Recent research indicates that the genetic profile of GBM makes it resistant to drugs and radiation. However, the main obstacle in treating GBM is transporting drugs through the blood-brain barrier (BBB). Albumin is a versatile biomaterial for the synthesis of nanoparticles. The efficiency of albumin-based delivery systems is determined by their ability to improve tumor targeting and accumulation. In this review, we will discuss the prevalence of human glioblastoma and the currently adopted treatment, as well as the structure and some essential functions of the BBB, to transport drugs through this barrier. We will also mention some aspects related to the blood-tumor brain barrier (BTBB) that lead to poor treatment efficacy. The properties and structure of serum albumin were highlighted, such as its role in targeting brain tumors, as well as the progress made until now regarding the techniques for obtaining albumin nanoparticles and their functionalization, in order to overcome the BBB and treat cancer, especially human glioblastoma. The albumin drug delivery nanosystems mentioned in this paper have improved properties and can overcome the BBB to target brain tumors.
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Affiliation(s)
- Camelia-Elena Tincu (Iurciuc)
- Department of Natural and Synthetic Polymers, “Cristofor Simionescu” Faculty of Chemical Engineering and Protection of the Environment, “Gheorghe Asachi” Technical University, 73, Prof. Dimitrie Mangeron Street, 700050 Iasi, Romania;
- Department of Pharmaceutical Technology, Faculty of Pharmacy, “Grigore T. Popa” University of Medicine and Pharmacy, 16, University Street, 700115 Iasi, Romania;
| | - Călin Vasile Andrițoiu
- Apitherapy Medical Center, Balanesti, Nr. 336-337, 217036 Gorj, Romania;
- Specialization of Nutrition and Dietetics, Faculty of Pharmacy, Vasile Goldis Western University of Arad, Liviu Rebreanu Street, 86, 310045 Arad, Romania
| | - Marcel Popa
- Department of Natural and Synthetic Polymers, “Cristofor Simionescu” Faculty of Chemical Engineering and Protection of the Environment, “Gheorghe Asachi” Technical University, 73, Prof. Dimitrie Mangeron Street, 700050 Iasi, Romania;
- Faculty of Dental Medicine, “Apollonia” University of Iasi, 11, Pacurari Street, 700511 Iasi, Romania
- Academy of Romanian Scientists, 3 Ilfov Street, 050045 Bucharest, Romania
| | - Lăcrămioara Ochiuz
- Department of Pharmaceutical Technology, Faculty of Pharmacy, “Grigore T. Popa” University of Medicine and Pharmacy, 16, University Street, 700115 Iasi, Romania;
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2
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Fluorinated Human Serum Albumin as Potential 19F Magnetic Resonance Imaging Probe. Molecules 2023; 28:molecules28041695. [PMID: 36838682 PMCID: PMC9959765 DOI: 10.3390/molecules28041695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 02/06/2023] [Accepted: 02/09/2023] [Indexed: 02/12/2023] Open
Abstract
Fluorinated human serum albumin conjugates were prepared and tested as potential metal-free probes for 19F magnetic resonance imaging (MRI). Each protein molecule was modified by several fluorine-containing compounds via the N-substituted natural acylating reagent homocysteine thiolactone. Albumin conjugates retain the protein's physical and biological properties, such as its 3D dimensional structure, aggregation ability, good solubility, proteolysis efficiency, biocompatibility, and low cytotoxicity. A dual-labeled with cyanine 7 fluorescence dye and fluorine reporter group albumin were synthesized for simultaneous fluorescence imaging and 19F MRI. The preliminary in vitro studies show the prospects of albumin carriers for multimodal imaging.
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Zhu L, Li Y, Jiang M, Ke C, Long H, Qiu M, Zhang L, Ye C, Zhou X, Jiang ZX, Chen S. Self-Assembly of Precisely Fluorinated Albumin for Dual Imaging-Guided Synergistic Chemo-Photothermal-Photodynamic Cancer Therapy. ACS APPLIED MATERIALS & INTERFACES 2023; 15:2665-2678. [PMID: 36604154 DOI: 10.1021/acsami.2c19161] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Although albumin has been extensively used in nanomedicine, it is still challenging to fluorinate albumin into fluorine-19 magnetic resonance imaging (19F MRI)-traceable theranostics because existing strategies lead to severe 19F signal splitting, line broadening, and low 19F MRI sensitivity. To this end, 34-cysteine-selectively fluorinated bovine serum albumins (BSAs) with a sharp singlet 19F peak have been developed as 19F MRI-sensitive and self-assembled frameworks for cancer theranostics. It was found that fluorinated albumin with a non-binding fluorocarbon and a long linker is crucial for avoiding 19F signal splitting and line broadening. With the fluorinated BSAs, paclitaxel (PTX) and IR-780 were self-assembled into stable, monodisperse, and multifunctional nanoparticles in a framework-promoted self-emulsion way. The high tumor accumulation, efficient cancer cell uptake, and laser-triggered PTX sharp release of the BSA nanoparticles enabled 19F MRI-near infrared fluorescence imaging (NIR FLI)-guided synergistic chemotherapy (Chemo), photothermal and photodynamic therapy of xenograft MCF-7 cancer with a high therapeutical index in mice. This study developed a rational synthesis of 19F MRI-sensitive albumin and a framework-promoted self-emulsion of multifunctional BSA nanoparticles, which would promote the development of protein-based high-performance biomaterials for imaging, diagnosis, therapy, and beyond.
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Affiliation(s)
- Lijun Zhu
- School of Pharmaceutical Sciences, Wuhan University, Wuhan430071, China
| | - Yu Li
- Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan430071, China
| | - Mou Jiang
- Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan430071, China
| | - Changsheng Ke
- School of Pharmaceutical Sciences, Wuhan University, Wuhan430071, China
| | - Hanxiong Long
- School of Pharmaceutical Sciences, Wuhan University, Wuhan430071, China
| | - Maosong Qiu
- Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan430071, China
| | - Lei Zhang
- Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan430071, China
| | - Chaohui Ye
- Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan430071, China
| | - Xin Zhou
- Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan430071, China
| | - Zhong-Xing Jiang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan430071, China
- University of Chinese Academy of Sciences, Beijing100049, China
| | - Shizhen Chen
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan430071, China
- University of Chinese Academy of Sciences, Beijing100049, China
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4
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Ellefsen JD, Miller SJ. Photocatalytic Reductive Olefin Hydrodifluoroalkylation Enabled by Tertiary Amine Reductants Compatible with Complex Systems. J Org Chem 2022; 87:10250-10255. [PMID: 35829693 PMCID: PMC9357216 DOI: 10.1021/acs.joc.2c01231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Noncanonical amino acids (NCAAs) are imperative to many facets of chemistry and biology. Herein, we report a method for the reductive hydrodifluoroalkylation of olefins that utilizes triethylamine base as the terminal reductant. The alkene acceptors include a range of electronically diverse alkenes, chief among them, dehydroalanine in variously protected forms, which provides access to synthetically relevant NCAA scaffolds under mild and general reaction conditions. We have demonstrated that a chiral auxiliary may be incorporated to provide diastereocontrol for pro-stereogenic substrates. Mechanistically motivated experiments provide some insight into the reaction mechanism, which supports a terminal step involving proton transfer for electron-poor olefins, while H atom transfer assisted by a thiol cocatalyst may complete the catalytic cycle for electron-rich olefins. The protocol is found to be compatible with additions to complex molecules, including the natural product thiostrepton.
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Affiliation(s)
- Jonathan D Ellefsen
- Department of Chemistry, Yale University, P.O. Box 208107, New Haven, Connecticut 06520-8107, United States
| | - Scott J Miller
- Department of Chemistry, Yale University, P.O. Box 208107, New Haven, Connecticut 06520-8107, United States
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Du L, Helsper S, Nosratabad NA, Wang W, Fadool DA, Amiens C, Grant S, Mattoussi H. A Multifunctional Contrast Agent for 19F-Based Magnetic Resonance Imaging. Bioconjug Chem 2022; 33:881-891. [PMID: 35446553 DOI: 10.1021/acs.bioconjchem.2c00116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Magnetic resonance imaging, MRI, relying on 19F nuclei has attracted much attention, because the isotopes exhibit a high gyromagnetic ratio (comparable to that of protons) and have 100% natural abundance. Furthermore, due to the very low traces of intrinsic fluorine in biological tissues, fluorine labeling allows easy visualization in vivo using 19F-based MRI. However, one of the drawbacks of the available fluorine tracers is their very limited solubility in water. Here, we detail the design and preparation of a set of water-compatible fluorine-rich polymers as contrast agents that can enhance the effectiveness of 19F-based MRI. The agents are synthesized using the nucleophilic addition reaction between poly(isobutylene-alt-maleic anhydride) copolymer and a mixture of amine-appended fluorine groups and polyethylene glycol (PEG) blocks. This allows control over the polymer architecture and stoichiometry, resulting in good affinity to water solutions. We further investigate the effects of introducing additional segmental mobility to the fluorine moieties in the polymer, by inserting a PEG linker between the moieties and the polymer backbone. We find that controlling the polymer stoichiometry and introducing additional segmental mobility enhance the NMR signals and narrow the peak profile. In particular, we assess the impact of the PEG linker on T2* and T1 relaxation times, using a series of gradient-recalled echo images with varying echo times, TE, or recovery time, TR, respectively. We find that for equivalent concentrations, the PEG linker greatly increases T2*, while maintaining high T1 values, as compared to polymers without this linker. Phantom images collected from these compounds show bright signals over a background with high intensities.
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Affiliation(s)
- Liang Du
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, Florida 32306, United States
| | - Shannon Helsper
- The National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32306, United States.,FAMU-FSU Chemical and Biomedical Engineering, Florida State University, Tallahassee, Florida 32306, United States
| | - Neda Arabzadeh Nosratabad
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, Florida 32306, United States
| | - Wentao Wang
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, Florida 32306, United States
| | - Debra Ann Fadool
- Department of Biological Science, Florida State University, Tallahassee, Florida 32306, United States
| | - Catherine Amiens
- LCC-CNRS, Université de Toulouse, UPS, 205 route de Narbonne, BP 44099, F-31077-Toulouse, Cedex 4, France
| | - Samuel Grant
- The National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32306, United States.,FAMU-FSU Chemical and Biomedical Engineering, Florida State University, Tallahassee, Florida 32306, United States
| | - Hedi Mattoussi
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, Florida 32306, United States
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7
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Popova TV, Krumkacheva OA, Burmakova AS, Spitsyna AS, Zakharova OD, Lisitskiy VA, Kirilyuk IA, Silnikov VN, Bowman MK, Bagryanskaya EG, Godovikova TS. Protein modification by thiolactone homocysteine chemistry: a multifunctionalized human serum albumin theranostic. RSC Med Chem 2020; 11:1314-1325. [PMID: 34085043 PMCID: PMC8126878 DOI: 10.1039/c9md00516a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 03/23/2020] [Indexed: 01/15/2023] Open
Abstract
As the most abundant protein with a variety of physiological functions, albumin has been used extensively for the delivery of therapeutic molecules. Thiolactone chemistry provides a powerful tool to prepare spin-labeled albumin-based multimodal imaging probes and therapeutic agents. We report the synthesis of a tamoxifen homocysteine thiolactone derivative and its use in thiol-'click' chemistry to prepare multi-functionalized serum albumin. The released sulfhydryl group of the homocysteine functional handle was labeled with a nitroxide reagent to prepare a spin-labeled albumin-tamoxifen conjugate confirmed by MALDI-TOF-MS, EPR spectroscopy, UV-vis and fluorescent emission spectra. This is the basis for a novel multimodal tamoxifen-albumin theranostic with a significant (dose-dependent) inhibitory effect on the proliferation of malignant cells. The response of human glioblastoma multiforme T98G cells and breast cancer MCF-7 cells to tamoxifen and its albumin conjugates was different in tumor cells with different expression level of ERα in our experiments. These results provide further impetus to develop a serum protein for delivery of tamoxifen to cancer cells.
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Affiliation(s)
- Tatyana V Popova
- Institute of Chemical Biology and Fundamental Medicine SB RAS 630090 Novosibirsk Russia
- Novosibirsk State University 630090 Novosibirsk Russia
| | - Olesya A Krumkacheva
- Novosibirsk State University 630090 Novosibirsk Russia
- International Tomography Center SB RAS 630090 Novosibirsk Russia
| | - Anna S Burmakova
- Institute of Chemical Biology and Fundamental Medicine SB RAS 630090 Novosibirsk Russia
- Novosibirsk State University 630090 Novosibirsk Russia
| | - Anna S Spitsyna
- Novosibirsk State University 630090 Novosibirsk Russia
- Novosibirsk Institute of Organic Chemistry SB RAS 630090 Novosibirsk Russia
| | - Olga D Zakharova
- Institute of Chemical Biology and Fundamental Medicine SB RAS 630090 Novosibirsk Russia
| | - Vladimir A Lisitskiy
- Institute of Chemical Biology and Fundamental Medicine SB RAS 630090 Novosibirsk Russia
| | - Igor A Kirilyuk
- Novosibirsk Institute of Organic Chemistry SB RAS 630090 Novosibirsk Russia
| | - Vladimir N Silnikov
- Institute of Chemical Biology and Fundamental Medicine SB RAS 630090 Novosibirsk Russia
| | - Michael K Bowman
- Novosibirsk Institute of Organic Chemistry SB RAS 630090 Novosibirsk Russia
- University of Alabama Tuscaloosa Alabama 35487-0336 USA
| | - Elena G Bagryanskaya
- Novosibirsk State University 630090 Novosibirsk Russia
- Novosibirsk Institute of Organic Chemistry SB RAS 630090 Novosibirsk Russia
| | - Tatyana S Godovikova
- Institute of Chemical Biology and Fundamental Medicine SB RAS 630090 Novosibirsk Russia
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8
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Somlyay M, Ledolter K, Kitzler M, Sandford G, Cobb SL, Konrat R. 19 F NMR Spectroscopy Tagging and Paramagnetic Relaxation Enhancement-Based Conformation Analysis of Intrinsically Disordered Protein Complexes. Chembiochem 2019; 21:696-701. [PMID: 31529763 DOI: 10.1002/cbic.201900453] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Indexed: 11/06/2022]
Abstract
The combination of 19 F NMR spectroscopy tagging and paramagnetic relaxation enhancement (PRE) NMR spectroscopy experiments was evaluated as a versatile method to probe protein-protein interactions and conformational changes of intrinsically disordered proteins upon complex formation. The feasibility of the approach is illustrated with an application to the Myc-Max protein complex; this is an oncogenic transcription factor that binds enhancer box DNA fragments. The single cysteine residue of Myc was tagged with highly fluorinated [19 F]3,5-bis(trifluoromethyl)benzyl bromide. Structural dynamics of the protein complex were monitored through intermolecular PREs between 19 F-Myc and paramagnetic (1-oxyl-2,2,5,5-tetramethyl-Δ3-pyrroline-3-methyl)methanethiosulfonate (MTSL)-tagged) Max. The 19 F R2 relaxation rates obtained with three differently MTSL-tagged Max mutants revealed novel insights into the differential structural dynamics of Myc-Max bound to DNA and the tumour suppressor breast cancer antigen 1. Given its ease of implementation, fruitful applications of this strategy to structural biology and inhibitor screening can be envisaged.
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Affiliation(s)
- Máté Somlyay
- Department of Structural and Computational Biology, Max F. Perutz Laboratories, University of Vienna, Campus Vienna Biocenter 5, 1030, Vienna, Austria
| | - Karin Ledolter
- Department of Structural and Computational Biology, Max F. Perutz Laboratories, University of Vienna, Campus Vienna Biocenter 5, 1030, Vienna, Austria
| | - Manuel Kitzler
- Department of Structural and Computational Biology, Max F. Perutz Laboratories, University of Vienna, Campus Vienna Biocenter 5, 1030, Vienna, Austria
| | - Graham Sandford
- Department of Chemistry, Durham University, Stockton Road, DH1 3LE, Durham, UK
| | - Steven L Cobb
- Department of Chemistry, Durham University, Stockton Road, DH1 3LE, Durham, UK
| | - Robert Konrat
- Department of Structural and Computational Biology, Max F. Perutz Laboratories, University of Vienna, Campus Vienna Biocenter 5, 1030, Vienna, Austria
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9
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Weber DK, Bader T, Larsen EK, Wang S, Gopinath T, Distefano M, Veglia G. Cysteine-ethylation of tissue-extracted membrane proteins as a tool to detect conformational states by solid-state NMR spectroscopy. Methods Enzymol 2019; 621:281-304. [PMID: 31128784 DOI: 10.1016/bs.mie.2019.02.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
Solid-state NMR (ssNMR) is an ideal tool to study structure and dynamics of membrane proteins in their native lipid environment. In principle, ssNMR has no size limitations. However, this feature is rarely exploited as large membrane proteins display severe resonance overlap. In addition, dismal yields from recombinant bacterial expression systems limit severely spectroscopic characterization of membrane proteins. For very large mammalian membrane proteins, extraction from the original organism remains the most viable approach. In this case, NMR-observable nuclei must be introduced post-translationally, but the approaches developed so far are rather scarce. Here, we detail the synthesis and engineering of a reactive 13C-ethylmethanethiosulfonate (13C-EMTS) reagent for the post-translational alkylation of cysteine sidechains of a 110kDa sarcoplasmic reticulum Ca2+-ATPase (SERCA) extracted from rabbit skeletal muscle tissue. When reconstituted into liposomes, it is possible to resolve the resonances of the engineered ethyl groups by magic-angle spinning (MAS) 2D [13C,13C]-DARR experiments. Notably, the ethyl-group modification does not perturb the function of SERCA, yielding well-resolved 13C-13C fingerprints that are used to image its structural states in the catalytic cycle and filtering out overwhelming naturally-abundant 13C nuclei signals arising from the enzyme and lipids. We anticipate that this approach will be used together with 19F NMR to monitor conformational transitions of enzymes and proteins that are difficult to express recombinantly.
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Affiliation(s)
- Daniel K Weber
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, United States
| | - Taysir Bader
- Department of Chemistry, University of Minnesota, Minneapolis, MN, United States
| | - Erik K Larsen
- Department of Chemistry, University of Minnesota, Minneapolis, MN, United States
| | - Songlin Wang
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, United States
| | - Tata Gopinath
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, United States
| | - Mark Distefano
- Department of Chemistry, University of Minnesota, Minneapolis, MN, United States
| | - Gianluigi Veglia
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, United States; Department of Chemistry, University of Minnesota, Minneapolis, MN, United States.
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10
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Bondarenko V, Wells M, Xu Y, Tang P. Solution NMR Studies of Anesthetic Interactions with Ion Channels. Methods Enzymol 2018; 603:49-66. [PMID: 29673534 DOI: 10.1016/bs.mie.2018.01.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
NMR spectroscopy is one of the major tools to provide atomic resolution protein structural information. It has been used to elucidate the molecular details of interactions between anesthetics and ion channels, to identify anesthetic binding sites, and to characterize channel dynamics and changes introduced by anesthetics. In this chapter, we present solution NMR methods essential for investigating interactions between ion channels and general anesthetics, including both volatile and intravenous anesthetics. Case studies are provided with a focus on pentameric ligand-gated ion channels and the voltage-gated sodium channel NaChBac.
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Affiliation(s)
- Vasyl Bondarenko
- University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Marta Wells
- University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Yan Xu
- University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Pei Tang
- University of Pittsburgh School of Medicine, Pittsburgh, PA, United States.
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11
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Alvares RDA, Szulc DA, Cheng HLM. A scale to measure MRI contrast agent sensitivity. Sci Rep 2017; 7:15493. [PMID: 29138455 PMCID: PMC5686147 DOI: 10.1038/s41598-017-15732-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 11/01/2017] [Indexed: 01/17/2023] Open
Abstract
Magnetic resonance imaging (MRI) provides superior resolution of anatomical features and the best soft tissue contrast, and is one of the predominant imaging modalities. With this technique, contrast agents are often used to aid discrimination by enhancing specific features. Over the years, a rich diversity of such agents has evolved and with that, so has a need to systematically sort contrast agents based on their efficiency, which directly determines sensitivity. Herein, we present a scale to rank MRI contrast agents. The scale is based on analytically determining the minimum detectable concentration of a contrast agent, and employing a ratiometric approach to standardize contrast efficiency to a benchmark contrast agent. We demonstrate the approach using several model contrast agents and compare the relative sensitivity of these agents for the first time. As the first universal metric of contrast agent sensitivity, this scale will be vital to easily assessing contrast agent efficiency and thus important to promoting use of some of the elegant and diverse contrast agents in research and clinical practice.
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Affiliation(s)
- Rohan D A Alvares
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, Ontario, Canada
| | - Daniel A Szulc
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, Ontario, Canada
| | - Hai-Ling M Cheng
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada.
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, Ontario, Canada.
- The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada.
- Ontario Institute for Regenerative Medicine, Toronto, Ontario, Canada.
- Heart & Stroke/Richard Lewar Centre of Excellence for Cardiovascular Research, Toronto, Ontario, Canada.
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Abstract
BACKGROUND Identifying functionally relevant anesthetic-binding sites in pentameric ligand-gated ion channels (pLGICs) is an important step toward understanding the molecular mechanisms underlying anesthetic action. The anesthetic propofol is known to inhibit cation-conducting pLGICs, including a prokaryotic pLGIC from Erwinia chrysanthemi (ELIC), but the sites responsible for functional inhibition remain undetermined. METHODS We photolabeled ELIC with a light-activated derivative of propofol (AziPm) and performed fluorine-19 nuclear magnetic resonance experiments to support propofol binding to a transmembrane domain (TMD) intrasubunit pocket. To differentiate sites responsible for propofol inhibition from those that are functionally irrelevant, we made an ELIC-γ-aminobutyric acid receptor (GABAAR) chimera that replaced the ELIC-TMD with the α1β3GABAAR-TMD and compared functional responses of ELIC-GABAAR and ELIC with propofol modulations. RESULTS Photolabeling showed multiple AziPm-binding sites in the extracellular domain (ECD) but only one site in the TMD with labeled residues M265 and F308 in the resting state of ELIC. Notably, this TMD site is an intrasubunit pocket that overlaps with binding sites for anesthetics, including propofol, found previously in other pLGICs. Fluorine-19 nuclear magnetic resonance experiments supported propofol binding to this TMD intrasubunit pocket only in the absence of agonist. Functional measurements of ELIC-GABAAR showed propofol potentiation of the agonist-elicited current instead of inhibition observed on ELIC. CONCLUSIONS The distinctly different responses of ELIC and ELIC-GABAAR to propofol support the functional relevance of propofol binding to the TMD. Combining the newly identified TMD intrasubunit pocket in ELIC with equivalent TMD anesthetic sites found previously in other cationic pLGICs, we propose this TMD pocket as a common site for anesthetic inhibition of pLGICs.
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13
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Chubarov AS, Zakharova OD, Koval OA, Romaschenko AV, Akulov AE, Zavjalov EL, Razumov IA, Koptyug IV, Knorre DG, Godovikova TS. Design of protein homocystamides with enhanced tumor uptake properties for (19)F magnetic resonance imaging. Bioorg Med Chem 2015; 23:6943-54. [PMID: 26462051 DOI: 10.1016/j.bmc.2015.09.043] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 08/27/2015] [Accepted: 09/26/2015] [Indexed: 02/06/2023]
Abstract
Straightforward and reliable tools for in vivo imaging of tumors can benefit the studies of cancer development, as well as contribute to successful diagnosis and treatment of cancer. (19)F NMR offers an exceptional quantitative way of in vivo imaging of the infused agents because of the lack of (19)F signals from the endogenous molecules in the body. The purpose of this study is to develop molecular probes with appropriate NMR characteristics and the biocompatibility for in vivo applications using (19)F MRI. We have studied the reaction between perfluorotoluene and homocysteine thiolactone resulting in the formation of N-substituted homocysteine thiolactone derivative. It has been shown that the reaction occurs selectively at the para position. This fluorine-labeled homocysteine thiolactone has been employed for the introduction of a perfluorotoluene group as a (19)F-containing tag into human serum albumin. The modified protein has been studied in terms of its ability to aggregate and promote the formation of free radicals. By comparing the properties of N-perfluorotoluene-homocystamide of albumin with N-homocysteinylated albumin, it has been revealed that blocking of the alpha-amino group of the homocysteine residue in the fluorinated albumin conjugate inhibits the dangerous aggregation process, as well as free radical formation. A dual-labeled albumin-based molecular probe for (19)F MRI and fluorescence microscopy has been obtained by functionalizing the protein with both maleimide of a fluorescent dye and a fluorinated thiolactone derivative. The incubation of cells with this conjugate did not reveal any significant reduction in cell viability with respect to the parent albumin. The perfluorotoluene-labeled albumin has been demonstrated to act as a promising agent for in vivo (19)F MRI.
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Affiliation(s)
- Alexey S Chubarov
- Institute of Chemical Biology and Fundamental Medicine, SB RAS, 630090 Novosibirsk, Russia; Novosibirsk State University, 630090 Novosibirsk, Russia
| | - Olga D Zakharova
- Institute of Chemical Biology and Fundamental Medicine, SB RAS, 630090 Novosibirsk, Russia
| | - Olga A Koval
- Institute of Chemical Biology and Fundamental Medicine, SB RAS, 630090 Novosibirsk, Russia
| | | | - Andrey E Akulov
- Institute of Cytology and Genetics, SB RAS, 630090 Novosibirsk, Russia
| | | | - Ivan A Razumov
- Institute of Cytology and Genetics, SB RAS, 630090 Novosibirsk, Russia
| | - Igor V Koptyug
- International Tomography Center, SB RAS, 630090 Novosibirsk, Russia
| | - Dmitry G Knorre
- Institute of Chemical Biology and Fundamental Medicine, SB RAS, 630090 Novosibirsk, Russia
| | - Tatyana S Godovikova
- Institute of Chemical Biology and Fundamental Medicine, SB RAS, 630090 Novosibirsk, Russia; Novosibirsk State University, 630090 Novosibirsk, Russia.
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14
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Kinde MN, Chen Q, Lawless MJ, Mowrey DD, Xu J, Saxena S, Xu Y, Tang P. Conformational Changes Underlying Desensitization of the Pentameric Ligand-Gated Ion Channel ELIC. Structure 2015; 23:995-1004. [PMID: 25960405 DOI: 10.1016/j.str.2015.03.017] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Revised: 03/24/2015] [Accepted: 03/30/2015] [Indexed: 11/18/2022]
Abstract
Structural rearrangements underlying functional transitions of pentameric ligand-gated ion channels (pLGICs) are not fully understood. Using (19)F nuclear magnetic resonance and electron spin resonance spectroscopy, we found that ELIC, a pLGIC from Erwinia chrysanthemi, expanded the extracellular end and contracted the intracellular end of its pore during transition from the resting to an apparent desensitized state. Importantly, the contraction at the intracellular end of the pore likely forms a gate to restrict ion transport in the desensitized state. This gate differs from the hydrophobic gate present in the resting state. Conformational changes of the TM2-TM3 loop were limited to the N-terminal end. The TM4 helices and the TM3-TM4 loop appeared relatively insensitive to agonist-mediated structural rearrangement. These results indicate that conformational changes accompanying functional transitions are not uniform among different ELIC regions. This work also revealed the co-existence of multiple conformations for a given state and suggested asymmetric conformational arrangements in a homomeric pLGIC.
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Affiliation(s)
- Monica N Kinde
- Department of Anesthesiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Qiang Chen
- Department of Anesthesiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Matthew J Lawless
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - David D Mowrey
- Department of Anesthesiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA; Department of Computational & Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Jiawei Xu
- Department of Anesthesiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Sunil Saxena
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Yan Xu
- Department of Anesthesiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA; Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA; Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Pei Tang
- Department of Anesthesiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA; Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA; Department of Computational & Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA.
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15
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More HT, Zhang KS, Srivastava N, Frezzo JA, Montclare JK. Influence of fluorination on protein-engineered coiled-coil fibers. Biomacromolecules 2015; 16:1210-7. [PMID: 25794312 DOI: 10.1021/bm5019062] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
We describe the design and characterization of fluorinated coiled-coil proteins able to assemble into robust nano- and microfibers. Fluorination is achieved biosynthetically by residue-specific incorporation of 5,5,5-trifluoroleucine (TFL). The fluorinated proteins C+TFL and Q+TFL are highly α-helical as confirmed via circular dichroism (CD) and more resistant to thermal denaturation compared to their nonfluorinated counterparts, C and Q. The fluorinated proteins demonstrate enhanced fiber assembly at pH 8.0 with higher order structure in contrast to nonfluorinated proteins, which are unable to form fibers under the same conditions. Ionic strength dependent fiber assembly is observed for fluorinated as well as wild-type proteins in which the fluorinated proteins exhibited more stable, thicker fibers. The fluorinated and nonfluorinated proteins reveal metal ion-dependent small molecule recognition and supramolecular assemblies. In the presence of Zn (II), enhanced thermal stability and fiber assembly is observed for the fluorinated proteins and their nonfluorinated counterparts. Whereas Ni (II) promotes aggregation with no fiber assembly, the stabilization of α-helix by Zn (II) results in enhanced binding to curcumin by the fluorinated proteins. Surprisingly, the nonfluorinated proteins exhibit multiple-fold increase in curcumin binding in the presence of Zn (II). In the context of the growing number of protein-based fiber assemblies, these fluorinated coiled-coil proteins introduce a new paradigm in the development of highly stable, robust self-assembling fibers under more physiologically relevant pH conditions that promotes the binding and release of small molecules in response to external cues.
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Affiliation(s)
- Haresh T More
- †Department of Chemical and Biomolecular Engineering, New York University Polytechnic School of Engineering, Brooklyn, New York 11201, United States
| | - Kevin S Zhang
- †Department of Chemical and Biomolecular Engineering, New York University Polytechnic School of Engineering, Brooklyn, New York 11201, United States
| | - Nikita Srivastava
- †Department of Chemical and Biomolecular Engineering, New York University Polytechnic School of Engineering, Brooklyn, New York 11201, United States
| | - Joseph A Frezzo
- †Department of Chemical and Biomolecular Engineering, New York University Polytechnic School of Engineering, Brooklyn, New York 11201, United States
| | - Jin K Montclare
- †Department of Chemical and Biomolecular Engineering, New York University Polytechnic School of Engineering, Brooklyn, New York 11201, United States.,∫Department of Biochemistry, SUNY Downstate Medical Center, Brooklyn, New York 11203, United States.,§Department of Chemistry, New York University, New York, New York 10003, United States
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17
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Bartusik D, Aebisher D. 19F applications in drug development and imaging – a review. Biomed Pharmacother 2014; 68:813-7. [DOI: 10.1016/j.biopha.2014.07.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 07/08/2014] [Indexed: 12/31/2022] Open
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18
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Yu YB. Fluorinated dendrimers as imaging agents for
19
F MRI. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2013; 5:646-61. [DOI: 10.1002/wnan.1239] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2013] [Revised: 06/10/2013] [Accepted: 07/09/2013] [Indexed: 11/10/2022]
Affiliation(s)
- Yihua Bruce Yu
- Department of Pharmaceutical Sciences University of Maryland Baltimore MD USA
- Fischell Department of Bioengineering University of Maryland College Park MD USA
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19
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Fluorine-19 NMR of integral membrane proteins illustrated with studies of GPCRs. Curr Opin Struct Biol 2013; 23:740-747. [PMID: 23932201 DOI: 10.1016/j.sbi.2013.07.011] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Accepted: 07/02/2013] [Indexed: 01/26/2023]
Abstract
Fluorine-19 is a spin-½ NMR isotope with high sensitivity and large chemical shift dispersion, which makes it attractive for high resolution NMR spectroscopy in solution. For studies of membrane proteins it is further of interest that (19)F is rarely found in biological materials, which enables observation of extrinsic (19)F labels with minimal interference from background signals. Today, after a period with rather limited use of (19)F NMR in structural biology, we witness renewed interest in this technology for studies of complex supramolecular systems. Here we report on recent (19)F NMR studies with the G protein-coupled receptor family of membrane proteins.
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21
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Yu JX, Hallac RR, Chiguru S, Mason RP. New frontiers and developing applications in 19F NMR. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2013; 70:25-49. [PMID: 23540575 PMCID: PMC3613763 DOI: 10.1016/j.pnmrs.2012.10.001] [Citation(s) in RCA: 140] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 10/23/2012] [Indexed: 05/06/2023]
Affiliation(s)
- Jian-Xin Yu
- Laboratory of Prognostic Radiology, Division of Advanced Radiological Sciences, Department of Radiology, UT Southwestern Medical Center, Dallas, Texas
| | - Rami R. Hallac
- Laboratory of Prognostic Radiology, Division of Advanced Radiological Sciences, Department of Radiology, UT Southwestern Medical Center, Dallas, Texas
| | - Srinivas Chiguru
- Laboratory of Prognostic Radiology, Division of Advanced Radiological Sciences, Department of Radiology, UT Southwestern Medical Center, Dallas, Texas
| | - Ralph P. Mason
- Laboratory of Prognostic Radiology, Division of Advanced Radiological Sciences, Department of Radiology, UT Southwestern Medical Center, Dallas, Texas
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22
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Kitevski-LeBlanc JL, Prosser RS. Current applications of 19F NMR to studies of protein structure and dynamics. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2012; 62:1-33. [PMID: 22364614 DOI: 10.1016/j.pnmrs.2011.06.003] [Citation(s) in RCA: 206] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Accepted: 07/01/2011] [Indexed: 05/20/2023]
Affiliation(s)
- Julianne L Kitevski-LeBlanc
- Department of Chemistry, University of Toronto, UTM, 3359 Mississauga Rd., North Mississauga, Ontario, Canada
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23
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Ogawa M, Kataoka H, Nitahara S, Fujimoto H, Aoki H, Ito S, Narazaki M, Matsuda T. Water-Soluble Fluorinated Polymer Nanoparticle as 19F MRI Contrast Agent Prepared by Living Random Copolymerization from Dendrimer Initiator. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2012. [DOI: 10.1246/bcsj.20110048] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Michihiro Ogawa
- Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University
| | - Hiromasa Kataoka
- Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University
| | - Satoshi Nitahara
- Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University
| | - Hiroyuki Fujimoto
- Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University
| | - Hiroyuki Aoki
- Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University
| | - Shinzaburo Ito
- Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University
| | - Michiko Narazaki
- Department of Systems Science, Graduate School of Informatics, Kyoto University
| | - Tetsuya Matsuda
- Department of Systems Science, Graduate School of Informatics, Kyoto University
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24
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Verardi R, Traaseth NJ, Masterson LR, Vostrikov VV, Veglia G. Isotope labeling for solution and solid-state NMR spectroscopy of membrane proteins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 992:35-62. [PMID: 23076578 PMCID: PMC3555569 DOI: 10.1007/978-94-007-4954-2_3] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
In this chapter, we summarize the isotopic labeling strategies used to obtain high-quality solution and solid-state NMR spectra of biological samples, with emphasis on integral membrane proteins (IMPs). While solution NMR is used to study IMPs under fast tumbling conditions, such as in the presence of detergent micelles or isotropic bicelles, solid-state NMR is used to study the structure and orientation of IMPs in lipid vesicles and bilayers. In spite of the tremendous progress in biomolecular NMR spectroscopy, the homogeneity and overall quality of the sample is still a substantial obstacle to overcome. Isotopic labeling is a major avenue to simplify overlapped spectra by either diluting the NMR active nuclei or allowing the resonances to be separated in multiple dimensions. In the following we will discuss isotopic labeling approaches that have been successfully used in the study of IMPs by solution and solid-state NMR spectroscopy.
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Affiliation(s)
- Raffaello Verardi
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455
| | | | | | | | - Gianluigi Veglia
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455
- Department of Chemistry, University of Minnesota, Minneapolis, MN 55455
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25
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Chubarov AS, Shakirov MM, Koptyug IV, Sagdeev RZ, Knorre DG, Godovikova TS. Synthesis and characterization of fluorinated homocysteine derivatives as potential molecular probes for 19 F magnetic resonance spectroscopy and imaging. Bioorg Med Chem Lett 2011; 21:4050-3. [DOI: 10.1016/j.bmcl.2011.04.119] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2011] [Revised: 04/26/2011] [Accepted: 04/26/2011] [Indexed: 10/18/2022]
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26
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Knight JC, Edwards PG, Paisey SJ. Fluorinated contrast agents for magnetic resonance imaging; a review of recent developments. RSC Adv 2011. [DOI: 10.1039/c1ra00627d] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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27
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Synthesis and Evaluation of Water-Soluble Fluorinated Dendritic Block-Copolymer Nanoparticles as a 19F-MRI Contrast Agent. MACROMOL CHEM PHYS 2010. [DOI: 10.1002/macp.201000100] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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28
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Nyström AM, Bartels JW, Du W, Wooley KL. Perfluorocarbon-loaded Shell Crosslinked Knedel-like Nanoparticles: Lessons regarding polymer mobility and self assembly. JOURNAL OF POLYMER SCIENCE. PART A, POLYMER CHEMISTRY 2009; 47:1023-1037. [PMID: 20157345 PMCID: PMC2779516 DOI: 10.1002/pola.23184] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Reversible addition-fragmentation chain transfer polymerization was employed to synthesize a set of copolymers of styrene (PS) and 2,3,4,5,6-pentafluorostyrene (PPFS), as well as block copolymers with tert-butyl acrylate (PtBA)-b-PS-co-PPFS, with control over molecular weight and polydispersity. It was found that the copolymerization of styrene and PFS allowed for the preparation of gradient copolymers with opposite levels of monomer consumption, depending on the feed ratio. Conversion to amphiphilic block copolymers, PAA-b-(PS-co-PPFS), by removing the protecting groups was followed by fitting with monomethoxy poly(ethylene glycol) chains. Solution-state assembly and intramicellar crosslinking afforded shell crosslinked (SCK) block copolymer nanoparticles. These fluorinated nanoparticles (ca. 20 nm diameters) were studied as potential magnetic resonance imaging (MRI) contrast agents based on the (19)F-nuclei, however, it was found that packaging of the hydrophobic fluorinated polymers into the core domain restricted the mobility of the chains and prohibited (19)F-NMR spectroscopy when the particles were dispersed in water without an organic cosolvent. Packing of perflouro-15-crown-5-ether (PFCE) into the polymer micelle was demonstrated with good uptake efficiency, however, it was necessary to swell the core with a good solvent (DMSO) to increase the mobility and observe the (19)F-NMR signal of the PFCE.
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Affiliation(s)
- Andreas M Nyström
- Department of Chemistry and Department of Radiology, Washington University in Saint Louis, Saint Louis, Missouri 63130-4899 (USA)
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29
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Jackson JC, Hammill JT, Mehl RA. Site-specific incorporation of a (19)F-amino acid into proteins as an NMR probe for characterizing protein structure and reactivity. J Am Chem Soc 2007; 129:1160-6. [PMID: 17263397 DOI: 10.1021/ja064661t] [Citation(s) in RCA: 150] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
19F NMR is a powerful tool for monitoring protein conformational changes and interactions; however, the inability to site-specifically introduce fluorine labels into proteins of biological interest severely limits its applicability. Using methods for genetically directing incorporation of unnatural amino acids, we have inserted trifluoromethyl-l-phenylalanine (tfm-Phe) into proteins in vivo at TAG nonsense codons with high translational efficiency and fidelity. The binding of substrates, inhibitors, and cofactors, as well as reactions in enzymes, were studied by selective introduction of tfm-Phe and subsequent monitoring of the 19F NMR chemical shifts. Subtle protein conformational changes were detected near the active site and at long distances (25 Angstrom). 19F signal sensitivity and resolution was also sufficient to differentiate protein environments in vivo. Since there has been interest in using 19F-labeled proteins in solid-state membrane protein studies, folding studies, and in vivo studies, this general method for genetically incorporating a 19F-label into proteins of any size in Escherichia coli should have broad application beyond that of monitoring protein conformational changes.
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Affiliation(s)
- Jennifer C Jackson
- Department of Chemistry, Franklin and Marshall College, P.O. Box 3003, Lancaster, Pennsylvania 17604, USA
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30
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Dzik-Jurasz AS, Wolber J, Prock T, Collins DJ, Leach MO, Rowland IJ. The quantitative 19F-imaging of albumin at 1.5 T: a potential in-vivo tool. Magn Reson Imaging 2001; 19:839-44. [PMID: 11551725 DOI: 10.1016/s0730-725x(01)00402-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
19F-MR-imaging has been used to quantitate albumin concentration in a phantom at 1.5 T. The experimentally derived relationship between albumin concentration and the T1 relaxation time of a fluorinated marker, tetrafluorosuccinic acid (TFSA) was used to calculate the albumin concentration from a quantitative 19F T1 map acquired using a gradient echo sequence. There was close correlation between calculated and actual BSA concentrations (r = 0.99, SE = 0.15). The potentially interfering effect of paramagnetic species on T1 relaxation times was also investigated. Relaxivity data show that albumin concentration measurements should be performed prior to any contrast agent administration.
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Affiliation(s)
- A S Dzik-Jurasz
- The CRC Clinical Magnetic Resonance Research Group, SM2 5PT, Sutton, UK.
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31
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Mehta VD, Sivasubramanian A, Kulkarni PV, Mason RP, Antich PP. 6-Fluoropyridoxal polymer conjugates: novel 19F pH indicators for magnetic resonance spectroscopy. Bioconjug Chem 1996; 7:536-40. [PMID: 8889013 DOI: 10.1021/bc9600527] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Fluorinated macromolecular probes (6-fluoropyridoxal-polymer conjugates) have been synthesized and characterized as potential pH indicators for magnetic resonance spectroscopy and imaging applications. The 19F pH sensor 2-fluoro-5-hydroxy-3-(hydroxymethyl)-6-methyl-4-pyridinecarboxal-+ ++dehyde (6-fluoropyridoxal; 2) has been conjugated to carrier molecules (polyamino dextran, polylysine, and albumin) by reductive alkylation for enhanced vascular retention and tissue targeting. The pH indicator polymer conjugates were purified by exhaustive dialysis and isolated in good yields (66-84%). The 6-fluoropyridoxal-polymer conjugates exhibit excellent 19F pH sensitivity and pKa suitable for in vivo studies. The potential application of these polymeric indicators has been demonstrated in whole blood. These novel macromolecular pH probes offer a new approach for studying tissue physiology.
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Affiliation(s)
- V D Mehta
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas 75235, USA
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