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Gallo-Rodriguez C, Rodriguez JB. Organoselenium Compounds in Medicinal Chemistry. ChemMedChem 2024; 19:e202400063. [PMID: 38778500 DOI: 10.1002/cmdc.202400063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 05/09/2024] [Accepted: 05/22/2024] [Indexed: 05/25/2024]
Abstract
The chemical and biological interest in this element and the molecules bearing selenium has been exponentially growing over the years. Selenium, formerly designated as a toxin, becomes a vital trace element for life that appears as selenocysteine and its dimeric form, selenocystine, in the active sites of selenoproteins, which catalyze a wide variety of reactions, including the detoxification of reactive oxygen species and modulation of redox activities. From the point of view of drug developments, organoselenium drugs are isosteres of sulfur-containing and oxygen-containing drugs with the advantage that the presence of the selenium atom confers antioxidant properties and high lipophilicity, which would increase cell membrane permeation leading to better oral bioavailability. This statement is the paramount relevance considering the big number of clinically employed compounds bearing sulfur or oxygen atoms in their structures including nucleosides and carbohydrates. Thus, in this article we have focused on the relevant features of the application of selenium in medicinal chemistry. With the increasing interest in selenium chemistry, we have attempted to highlight the most significant published data on this subject, mainly concentrating the analysis on the last years. In consequence, the recent advances of relevant pharmacological organoselenium compounds are discussed.
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Affiliation(s)
- Carola Gallo-Rodriguez
- Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, C1428EHA, Buenos Aires, Argentina
- CONICET-Universidad de Buenos Aires, Centro de Investigaciones en Hidratos de Carbono (CIHIDECAR), C1428EHA, Buenos Aires, Argentina
| | - Juan B Rodriguez
- Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, C1428EHA, Buenos Aires, Argentina
- CONICET-Universidad de Buenos Aires, Unidad de Microanálisis y Métodos Físicos en Química Orgánica (UMYMFOR), C1428EHA, Buenos, Aires, Argentina
- CONICET-Universidad de Buenos Aires, Centro de Investigaciones en Hidratos de Carbono (CIHIDECAR), C1428EHA, Buenos Aires, Argentina
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2
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Gerothanassis IP, Kridvin LB. 33S NMR: Recent Advances and Applications. Molecules 2024; 29:3301. [PMID: 39064879 PMCID: PMC11280432 DOI: 10.3390/molecules29143301] [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: 06/23/2024] [Revised: 07/05/2024] [Accepted: 07/09/2024] [Indexed: 07/28/2024] Open
Abstract
The purpose of this review is to present advances and applications of 33S NMR, which is an underutilized NMR spectroscopy. Experimental NMR aspects in solution, chemical shift tendencies, and quadrupolar relaxation parameters will be briefly summarized. Emphasis will be given to advances and applications in the emerging fields of solid-state and DFT computations of 33S NMR parameters. The majority of the examples were taken from the last twenty years and were selected on the basis of their importance to provide structural, electronic, and dynamic information that is difficult to obtain by other techniques.
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Affiliation(s)
- Ioannis P. Gerothanassis
- Section of Organic Chemistry and Biochemistry, Department of Chemistry, University of Ioannina, GR-45110 Ioannina, Greece
| | - Leonid B. Kridvin
- A.E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Favorsky St. 1, 664033 Irkutsk, Russia
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3
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Koscielniak J, Li J, Sail D, Swenson R, Anklin C, Rozovsky S, Byrd RA. Exploring Sulfur Sites in Proteins via Triple-Resonance 1H-Detected 77Se NMR. J Am Chem Soc 2023; 145. [PMID: 37906952 PMCID: PMC10655107 DOI: 10.1021/jacs.3c07225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 10/11/2023] [Accepted: 10/12/2023] [Indexed: 11/02/2023]
Abstract
NMR spectroscopy has been applied to virtually all sites within proteins and biomolecules; however, the observation of sulfur sites remains very challenging. Recent studies have examined 77Se as a replacement for sulfur and applied 77Se NMR in both the solution and solid states. As a spin-1/2 nuclide, 77Se is attractive as a probe of sulfur sites, and it has a very large chemical shift range (due to a large chemical shift anisotropy), which makes it potentially very sensitive to structural and/or binding interactions as well as dynamics. Despite being a spin-1/2 nuclide, there have been rather limited studies of 77Se, and the ability to use 1H-indirect detection has been sparse. Some examples exist, but in the absence of a directly bonded, nonexchangeable 1H, these have been largely limited to smaller molecules. We develop and illustrate approaches using double-labeling of 13C and 77Se in proteins that enable more sensitive triple-resonance schemes via multistep coherence transfers and 1H-detection. These methods require specialized hardware and decoupling schemes, which we developed and will be discussed.
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Affiliation(s)
- Janusz Koscielniak
- Leidos
Biomedical Research, Inc., Frederick, Maryland 21702, United States
| | - Jess Li
- Center
for Structural Biology, National Cancer
Institute, Frederick, Maryland 21702-1201, United States
| | - Deepak Sail
- Chemistry
and Synthesis Center, National Heart Lung
and Blood Institute, Bethesda, Maryland 20814, United States
| | - Rolf Swenson
- Chemistry
and Synthesis Center, National Heart Lung
and Blood Institute, Bethesda, Maryland 20814, United States
| | - Clemens Anklin
- Bruker
BioSpin Corp., Billerica, Massachusetts 01821, United States
| | - Sharon Rozovsky
- Department
of Chemistry and Biochemistry, University
of Delaware, Newark, Delaware 19716, United States
| | - R. Andrew Byrd
- Center
for Structural Biology, National Cancer
Institute, Frederick, Maryland 21702-1201, United States
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4
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Müller VVL, Simpson PV, Peng K, Basu U, Moreth D, Nagel C, Türck S, Oehninger L, Ott I, Schatzschneider U. Taming the Biological Activity of Pd(II) and Pt(II) Complexes with Triazolato "Protective" Groups: 1H, 77Se Nuclear Magnetic Resonance and X-ray Crystallographic Model Studies with Selenocysteine to Elucidate Differential Thioredoxin Reductase Inhibition. Inorg Chem 2023; 62:16203-16214. [PMID: 37713601 DOI: 10.1021/acs.inorgchem.3c02701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/17/2023]
Abstract
The biological activity of Pd(II) and Pt(II) complexes toward three different cancer cell lines as well as inhibition of selenoenzyme thioredoxin reductase (TrxR) was modulated in an unexpected way by the introduction of triazolate as a "protective group" to the inner metal coordination sphere using the iClick reaction of [M(N3)(terpy)]PF6 [M = Pd(II) or Pt(II) and terpy = 2,2':6',2″-terpyridine] with an electron-poor alkyne. In a cell proliferation assay using A549, HT-29, and MDA-MB-231 human cancer cell lines, the palladium compound was significantly more potent than the isostructural platinum analogue and exhibited submicromolar activity on the most responsive cell line. This difference was also reflected in the inhibitory efficiency toward TrxR with IC50 values of 0.1 versus 5.4 μM for the Pd(II) and Pt(II) complexes, respectively. UV/Vis kinetic studies revealed that the Pt compound binds to selenocysteine faster than to cysteine [k = (22.9 ± 0.2)·10-3 vs (7.1 ± 0.2)·10-3 s-1]. Selective triazolato ligand exchange of the title compounds with cysteine (Hcys) and selenocysteine (Hsec)─but not histidine (His) and 9-ethylguanine (9EtG)─was confirmed by 1H, 77Se, and 195Pt NMR spectroscopy. Crystal structures of three of the four ligand exchange products were obtained, including [Pt(sec)(terpy)]PF6 as the first metal complex of selenocysteine to be structurally characterized.
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Affiliation(s)
- Victoria V L Müller
- Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Peter V Simpson
- Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Kun Peng
- Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Uttara Basu
- Institut für Medizinische und Pharmazeutische Chemie, Technische Universität Braunschweig, Beethovenstr. 55, D-38106 Braunschweig, Germany
| | - Dominik Moreth
- Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Christoph Nagel
- Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Sebastian Türck
- Institut für Medizinische und Pharmazeutische Chemie, Technische Universität Braunschweig, Beethovenstr. 55, D-38106 Braunschweig, Germany
| | - Luciano Oehninger
- Institut für Medizinische und Pharmazeutische Chemie, Technische Universität Braunschweig, Beethovenstr. 55, D-38106 Braunschweig, Germany
| | - Ingo Ott
- Institut für Medizinische und Pharmazeutische Chemie, Technische Universität Braunschweig, Beethovenstr. 55, D-38106 Braunschweig, Germany
| | - Ulrich Schatzschneider
- Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
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5
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Wang T, Zhao Y, Wang M. Organic Selenium Compounds Determination in the Complex Matrix by the 1H-77Se HMBC Method. Microchem J 2022. [DOI: 10.1016/j.microc.2022.108032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/07/2022]
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6
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Quinn CM, Xu S, Hou G, Chen Q, Sail D, Byrd RA, Rozovsky S. 77Se- 13C based dipolar correlation experiments to map selenium sites in microcrystalline proteins. JOURNAL OF BIOMOLECULAR NMR 2022; 76:29-37. [PMID: 35320434 PMCID: PMC9195563 DOI: 10.1007/s10858-022-00390-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 01/14/2022] [Indexed: 06/14/2023]
Abstract
Sulfur-containing sites in proteins are of great importance for both protein structure and function, including enzymatic catalysis, signaling pathways, and recognition of ligands and protein partners. Selenium-77 is an NMR active spin-1/2 nucleus that shares many physiochemical properties with sulfur and can be readily introduced into proteins at sulfur sites without significant perturbations to the protein structure. The sulfur-containing amino acid methionine is commonly found at protein-protein or protein-ligand binding sites. Its selenium-containing counterpart, selenomethionine, has a broad chemical shift dispersion useful for NMR-based studies of complex systems. Methods such as (1H)-77Se-13C double cross polarization or {77Se}-13C REDOR could be valuable to map the local environment around selenium sites in proteins but have not been demonstrated to date. In this work, we explore these dipolar transfer mechanisms for structural characterization of the GB1 V39SeM variant of the model protein GB1 and demonstrate that 77Se-13C based correlations can be used to map the local environment around selenium sites in proteins. We have found that the general detection limit is ~ 5 Å, but longer range distances up to ~ 7 Å can be observed as well. This study establishes a framework for the future characterization of selenium sites at protein-protein or protein-ligand binding interfaces.
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Affiliation(s)
- Caitlin M. Quinn
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
| | - Shiping Xu
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
| | - Guangjin Hou
- State Key Laboratory of Catalysis, National Laboratory for Clean Energy, 2011-Collaborative Innovation Center of Chemistry for Energy Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian 116023, China
| | - Qingqing Chen
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
| | - Deepak Sail
- Chemistry and Synthesis Center, National Heart Lung and Blood Institute, Bethesda, MD, USA
| | - R. Andrew Byrd
- Center for Cancer Research, National Cancer Institute, Frederick, MD, USA
| | - Sharon Rozovsky
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
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7
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Henthorn JT, DeBeer S. Selenium Valence-to-Core X-ray Emission Spectroscopy and Kβ HERFD X-ray Absorption Spectroscopy as Complementary Probes of Chemical and Electronic Structure. Inorg Chem 2022; 61:2760-2767. [PMID: 35113562 PMCID: PMC8848279 DOI: 10.1021/acs.inorgchem.1c02802] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
![]()
Selenium X-ray absorption
spectroscopy (XAS) has found widespread
use in investigations of Se-containing materials, geochemical processes,
and biologically active sites. In contrast to sulfur Kβ X-ray
emission spectroscopy (XES), which has been found to contain electronic
and structural information complementary to S XAS, Se Kβ XES
remains comparatively underexplored. Herein, we present the first
Se Valence-to-Core (VtC) XES studies of reduced Se-containing compounds
and FeSe dimers. Se VtC XES is found to be sensitive to changes in
covalent Se bonding interactions (Se–Se/Se–C/Se–H
bonding) while being relatively insensitive to changes in Fe oxidation
states as selenide bridges in FeSe dimers ([Fe2Se2]2+ vs [Fe2Se2]+). In
contrast, Se Kβ HERFD XAS is demonstrated to be quite sensitive
to changes in the Fe oxidation state with Se Kβ HERFD XAS demonstrating
experimental resolution equivalent to Kα HERFD XAS. Additionally,
computational studies reveal both Se VtC XES and XAS to be sensitive
to selenium protonation in FeSe complexes. Selenium is a trace element that plays
vital roles in biological
and geochemical cycles, energy storage, photovoltaics, and nanomaterials.
Herein, selenium Valence-to-Core X-ray emission spectroscopy is explored
as a new method of probing the chemical and electronic structure in
selenium-containing compounds, demonstrating sensitivity to selenium
bonding interactions. When paired with high-resolution Se X-ray absorption
spectroscopy (HERFD XAS), these two methods have the potential to
reveal greater insight into protonation and redox changes of Se-substituted
FeS clusters.
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Affiliation(s)
- Justin T Henthorn
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Serena DeBeer
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
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8
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Rovó P. Recent advances in solid-state relaxation dispersion techniques. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2020; 108:101665. [PMID: 32574905 DOI: 10.1016/j.ssnmr.2020.101665] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 03/11/2020] [Accepted: 04/02/2020] [Indexed: 06/11/2023]
Abstract
This review describes two rotating-frame (R1ρ) relaxation dispersion methods, namely the Bloch-McConnell Relaxation Dispersion and the Near-rotary Resonance Relaxation Dispersion, which enable the study of microsecond time-scale conformational fluctuations in the solid state using magic-angle-spinning nuclear magnetic resonance spectroscopy. The goal is to provide the reader with key ideas, experimental descriptions, and practical considerations associated with R1ρ measurements that are needed for analyzing relaxation dispersion and quantifying conformational exchange. While the focus is on protein motion, many presented concepts can be equally well adapted to study the microsecond time-scale dynamics of other bio- (e.g. lipids, polysaccharides, nucleic acids), organic (e.g. pharmaceutical compounds), or inorganic molecules (e.g., metal organic frameworks). This article summarizes the essential contributions made by recent theoretical and experimental solid-state NMR studies to our understanding of protein motion. Here we discuss recent advances in fast MAS applications that enable the observation and atomic level characterization of sparsely populated conformational states which are otherwise inaccessible for other experimental methods. Such high-energy states are often associated with protein functions such as molecular recognition, ligand binding, or enzymatic catalysis, as well as with disease-related properties such as misfolding and amyloid formation.
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Affiliation(s)
- Petra Rovó
- Department of Chemistry, Ludwig Maximilian University Munich, Butenandtstr. 5-13, 81377, Munich, Germany; Center for NanoScience (CeNS), Schellingstr. 4, 80799, Munich, Germany.
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9
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Chen Q, Xu S, Lu X, Boeri MV, Pepelyayeva Y, Diaz EL, Soni SD, Allaire M, Forstner MB, Bahnson BJ, Rozovsky S. 77Se NMR Probes the Protein Environment of Selenomethionine. J Phys Chem B 2020; 124:601-616. [PMID: 31846581 DOI: 10.1021/acs.jpcb.9b07466] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Sulfur is critical for the correct structure and proper function of proteins. Yet, lacking a sensitive enough isotope, nuclear magnetic resonance (NMR) experiments are unable to deliver for sulfur in proteins the usual wealth of chemical, dynamic, and structural information. This limitation can be circumvented by substituting sulfur with selenium, which has similar physicochemical properties and minimal impact on protein structures but possesses an NMR compatible isotope (77Se). Here we exploit the sensitivity of 77Se NMR to the nucleus' chemical milieu and use selenomethionine as a probe for its proteinaceous environment. However, such selenium NMR spectra of proteins currently resist a reliable interpretation because systematic connections between variations of system variables and changes in 77Se NMR parameters are still lacking. To start narrowing this knowledge gap, we report here on a biological 77Se magnetic resonance data bank based on a systematically designed library of GB1 variants in which a single selenomethionine was introduced at different locations within the protein. We recorded the resulting isotropic 77Se chemical shifts and relaxation times for six GB1 variants by solution-state 77Se NMR. For four of the GB1 variants we were also able to determine the chemical shift anisotropy tensor of SeM by solid-state 77Se NMR. To enable interpretation of the NMR data, the structures of five of the GB1 variants were solved by X-ray crystallography to a resolution of 1.2 Å, allowing us to unambiguously determine the conformation of the selenomethionine. Finally, we combine our solution- and solid-state NMR data with the structural information to arrive at general insights regarding the execution and interpretation of 77Se NMR experiments that exploit selenomethionine to probe proteins.
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Affiliation(s)
- Qingqing Chen
- Department of Chemistry and Biochemistry , University of Delaware , Newark , Delaware 19716 , United States
| | - Shiping Xu
- Department of Chemistry and Biochemistry , University of Delaware , Newark , Delaware 19716 , United States
| | - Xingyu Lu
- Department of Chemistry and Biochemistry , University of Delaware , Newark , Delaware 19716 , United States.,Instrumentation and Service Center for Physical Sciences , Westlake University , Hangzhou , Zhejiang 310024 , China
| | - Michael V Boeri
- Department of Chemistry and Biochemistry , University of Delaware , Newark , Delaware 19716 , United States.,Neuroscience Department, Medical Toxicology Research Division , U.S. Army Medical Research Institute of Chemical Defense , 8350 Ricketts Point Road , Gunpowder , Maryland 21010 , United States
| | - Yuliya Pepelyayeva
- Department of Chemistry and Biochemistry , University of Delaware , Newark , Delaware 19716 , United States.,Department of Microbiology & Molecular Genetics, College of Osteopathic Medicine , Michigan State University , East Lansing , Michigan 48824 , United States
| | - Elizabeth L Diaz
- Department of Chemistry and Biochemistry , University of Delaware , Newark , Delaware 19716 , United States
| | - Sunil-Datta Soni
- Neuroscience Department, Medical Toxicology Research Division , U.S. Army Medical Research Institute of Chemical Defense , 8350 Ricketts Point Road , Gunpowder , Maryland 21010 , United States
| | - Marc Allaire
- Berkeley Center for Structural Biology, Molecular Biophysics & Integrated Bioimaging , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Martin B Forstner
- Department of Chemistry and Biochemistry , University of Delaware , Newark , Delaware 19716 , United States
| | - Brian J Bahnson
- Department of Chemistry and Biochemistry , University of Delaware , Newark , Delaware 19716 , United States
| | - Sharon Rozovsky
- Department of Chemistry and Biochemistry , University of Delaware , Newark , Delaware 19716 , United States
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10
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Application of Heteronuclear NMR Spectroscopy to Bioinorganic and Medicinal Chemistry ☆. REFERENCE MODULE IN CHEMISTRY, MOLECULAR SCIENCES AND CHEMICAL ENGINEERING 2018. [PMCID: PMC7157447 DOI: 10.1016/b978-0-12-409547-2.10947-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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11
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Senćanski M, Djordjević I, Grubišić S. Assessing the dispersive and electrostatic components of the selenium–aromatic interaction energy by DFT. J Mol Model 2017; 23:162. [DOI: 10.1007/s00894-017-3330-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 03/27/2017] [Indexed: 11/28/2022]
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12
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Liu J, Chen Q, Rozovsky S. Utilizing Selenocysteine for Expressed Protein Ligation and Bioconjugations. J Am Chem Soc 2017; 139:3430-3437. [PMID: 28186733 PMCID: PMC5824972 DOI: 10.1021/jacs.6b10991] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Employing selenocysteine-containing protein fragments to form the amide bond between respective protein fragments significantly extends the current capabilities of the widely used protein engineering method, expressed protein ligation. Selenocysteine-mediated ligation is noteworthy for its high yield and efficiency. However, it has so far been restricted to solid-phase synthesized seleno-peptides and thus constrained by where the selenocysteine can be positioned. Here we employ heterologously expressed seleno-fragments to overcome the placement and size restrictions in selenocysteine-mediated chemical ligation. Following ligation, the selenocysteine can be deselenized into an alanine or serine, resulting in nonselenoproteins. This greatly extends the flexibility in selecting the conjugation site in expressed protein ligations with no influence on native cysteines. Furthermore, the selenocysteine can be used to selectively introduce site-specific protein modifications. Therefore, selenocysteine-mediated expressed protein ligation simplifies incorporation of post-translational modifications into the protein scaffold.
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Affiliation(s)
| | | | - Sharon Rozovsky
- Department of Chemistry & Biochemistry, University of Delaware, Newark, DE, 19716
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13
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Lim JYC, Marques I, Thompson AL, Christensen KE, Félix V, Beer PD. Chalcogen Bonding Macrocycles and [2]Rotaxanes for Anion Recognition. J Am Chem Soc 2017; 139:3122-3133. [PMID: 28140582 DOI: 10.1021/jacs.6b12745] [Citation(s) in RCA: 154] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Electron-deficient heavy chalcogen atoms contain Lewis acidic σ-holes which are able to form attractive supramolecular interactions, known as chalcogen bonding (ChB), with Lewis bases. However, their potential in solution-phase anion binding applications is only just beginning to be realized in simple acyclic systems. Herein, we explore the 5-(methylchalcogeno)-1,2,3-triazole (chalcogen = Se, Te) motif as a novel ChB donor for anion binding. Other than being chemically robust enough to be incorporated into macrocyclic structures, thereby significantly expanding the scope and complexity of ChB host systems, we also demonstrate, by 1H NMR and DFT calculations, that the chalcogen atoms oriented within the macrocycle cavity are able to chelate copper(I) endotopically. Exploiting this property, the first examples of mechanically interlocked [2]rotaxanes containing ChB-donor groups are prepared via an active metal template strategy. Solution-phase 1H NMR and molecular modeling studies provide compelling evidence for the dominant influence of ChB in anion binding by these interlocked host systems. In addition, unprecedented charge-assisted ChB-mediated anion binding was also studied in aqueous solvent mixtures, which revealed considerable differences in anion recognition behavior in comparison with chalcogen-free host analogues. Moreover, DFT calculations and molecular dynamics simulations in aqueous solvent mixtures indicate that the selectivity is determined by the different hydrophilic characters of the anions allied to the hydration of the binding units in the presence of the anions. Exploiting the NMR-active nuclei of the ChB-donor chalcogen atoms, heteronuclear 77Se and 125Te NMR were used to directly study how anion recognition influences the local electronic environment of the chalcogen atoms in the mechanically bonded rotaxane binding sites in organic and aqueous solvent mixtures.
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Affiliation(s)
- Jason Y C Lim
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford , Mansfield Road, Oxford OX1 3TA, U.K
| | | | - Amber L Thompson
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford , Mansfield Road, Oxford OX1 3TA, U.K
| | - Kirsten E Christensen
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford , Mansfield Road, Oxford OX1 3TA, U.K
| | | | - Paul D Beer
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford , Mansfield Road, Oxford OX1 3TA, U.K
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14
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Watson MD, Peran I, Zou J, Bilsel O, Raleigh DP. Selenomethionine Quenching of Tryptophan Fluorescence Provides a Simple Probe of Protein Structure. Biochemistry 2017; 56:1085-1094. [DOI: 10.1021/acs.biochem.6b01000] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Matthew D. Watson
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Ivan Peran
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Junjie Zou
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
- Laufer
Center for Physical and
Quantitative Biology, Stony Brook University, Stony Brook, New York 11794, United States
| | - Osman Bilsel
- Department of Biochemistry and
Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, United States
| | - Daniel P. Raleigh
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
- Laufer
Center for Physical and
Quantitative Biology, Stony Brook University, Stony Brook, New York 11794, United States
- Graduate Program in Biochemistry & Structural Biology, Stony Brook University, Stony Brook, New York 11794, United States
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15
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16
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Fehér K, Timári I, Rákosi K, Szolomájer J, Illyés TZ, Bartok A, Varga Z, Panyi G, Tóth GK, Kövér KE. Probing pattern and dynamics of disulfide bridges using synthesis and NMR of an ion channel blocker peptide toxin with multiple diselenide bonds. Chem Sci 2016; 7:2666-2673. [PMID: 28660039 PMCID: PMC5477041 DOI: 10.1039/c5sc03995a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 12/17/2015] [Indexed: 12/28/2022] Open
Abstract
Anuroctoxin (AnTx), a 35-amino-acid scorpion toxin containing four disulfide bridges, is a high affinity blocker of the voltage-gated potassium channel Kv1.3, but also blocks Kv1.2. To improve potential therapeutic use of the toxin, we have designed a double substituted analog, [N17A/F32T]-AnTx, which showed comparable Kv1.3 affinity to the wild-type peptide, but also a 2500-fold increase in the selectivity for Kv1.3 over Kv1.2. In the present study we have achieved the chemical synthesis of a Sec-analog in which all cysteine (Cys) residues have been replaced by selenocysteine (Sec) forming four diselenide bonds. To the best of our knowledge this is the first time to replace, by chemical synthesis, all disulfide bonds with isosteric diselenides in a peptide/protein. Gratifyingly, the key pharmacological properties of the Sec-[N17A/F32T]-AnTx are retained since the peptide is functionally active. We also propose here a combined experimental and theoretical approach including NOE- and 77Se-based NMR supplemented by MD simulations for conformational and dynamic characterization of the Sec-[N17A/F32T]-AnTx. Using this combined approach allowed us to attain unequivocal assignment of all four diselenide bonds and supplemental MD simulations allowed characterization of the conformational dynamics around each disulfide/diselenide bridge.
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Affiliation(s)
- Krisztina Fehér
- Department of Inorganic and Analytical Chemistry , University of Debrecen , Egyetem tér 1 , H-4032 , Debrecen , Hungary .
- Department of Organic and Macromolecular Chemistry , Ghent University , Kringslaan 281 S4 , 9000 , Ghent , Belgium
| | - István Timári
- Department of Inorganic and Analytical Chemistry , University of Debrecen , Egyetem tér 1 , H-4032 , Debrecen , Hungary .
| | - Kinga Rákosi
- Department of Medical Chemistry , University of Szeged , Dóm tér 8 , H-6720 , Szeged , Hungary .
| | - János Szolomájer
- Department of Medical Chemistry , University of Szeged , Dóm tér 8 , H-6720 , Szeged , Hungary .
| | - Tünde Z Illyés
- Department of Organic Chemistry , University of Debrecen , Egyetem tér 1 , H-4032 , Debrecen , Hungary
| | - Adam Bartok
- Department of Biophysics and Cell Biology , University of Debrecen , Egyetem tér 1 , H-4012 , Debrecen , Hungary
| | - Zoltan Varga
- Department of Biophysics and Cell Biology , University of Debrecen , Egyetem tér 1 , H-4012 , Debrecen , Hungary
- MTA-DE-NAP B Ion Channel Structure-Function Research Group , Egyetem tér 1 , H-4032 , Debrecen , Hungary
| | - Gyorgy Panyi
- Department of Biophysics and Cell Biology , University of Debrecen , Egyetem tér 1 , H-4012 , Debrecen , Hungary
- MTA-DE Cell Biology and Signaling Research Group , University of Debrecen , Egyetem tér 1 , H-4032 , Debrecen , Hungary
| | - Gábor K Tóth
- Department of Medical Chemistry , University of Szeged , Dóm tér 8 , H-6720 , Szeged , Hungary .
| | - Katalin E Kövér
- Department of Inorganic and Analytical Chemistry , University of Debrecen , Egyetem tér 1 , H-4032 , Debrecen , Hungary .
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17
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Struppe J, Zhang Y, Rozovsky S. (77)Se chemical shift tensor of L-selenocystine: experimental NMR measurements and quantum chemical investigations of structural effects. J Phys Chem B 2015; 119:3643-50. [PMID: 25654666 DOI: 10.1021/jp510857s] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The genetically encoded amino acid selenocysteine and its dimeric form, selenocystine, are both utilized by nature. They are found in active sites of selenoproteins, enzymes that facilitate a diverse range of reactions, including the detoxification of reactive oxygen species and regulation of redox pathways. Due to selenocysteine and selenocystine's specialized biological roles, it is of interest to examine their (77)Se NMR properties and how those can in turn be employed to study biological systems. We report the solid-state (77)Se NMR measurements of the L-selenocystine chemical shift tensor, which provides the first experimental chemical shift tensor information on selenocysteine-containing systems. Quantum chemical calculations of L-selenocystine models were performed to help understand various structural effects on (77)Se L-selenocystine's chemical shift tensor. The effects of protonation state, protein environment, and substituent of selenium-bonded carbon on the isotropic chemical shift were found to be in a range of ca. 10-20 ppm. However, the conformational effect was found to be much larger, spanning ca. 600 ppm for the C-Se-Se-C dihedral angle range of -180° to +180°. Our calculations show that around the minimum energy structure with a C-Se-Se-C dihedral angle of ca. -90°, the energy costs to alter the dihedral angle in the range from -120° to -60° are within only 2.5 kcal/mol. This makes it possible to realize these conformations in a protein or crystal environment. (77)Se NMR was found to be a sensitive probe to such changes and has an isotropic chemical shift range of 272 ± 30 ppm for this energetically favorable conformation range. The energy-minimized structures exhibited calculated isotropic shifts that lay within 3-9% of those reported in previous solution NMR studies. The experimental solid-state NMR isotropic chemical shift is near the lower bound of this calculated range for these readily accessible conformations. These results suggest that the dihedral information may be deduced for a protein with appropriate structural models. These first-time experimental and theoretical results will facilitate future NMR studies of selenium-containing compounds and proteins.
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Affiliation(s)
- Jochem Struppe
- Bruker BioSpin Corporation, 15 Fortune Drive, Manning Park, Billerica, Massachusetts 01821, United States
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18
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Göbl C, Madl T, Simon B, Sattler M. NMR approaches for structural analysis of multidomain proteins and complexes in solution. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2014; 80:26-63. [PMID: 24924266 DOI: 10.1016/j.pnmrs.2014.05.003] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 05/14/2014] [Indexed: 05/22/2023]
Abstract
NMR spectroscopy is a key method for studying the structure and dynamics of (large) multidomain proteins and complexes in solution. It plays a unique role in integrated structural biology approaches as especially information about conformational dynamics can be readily obtained at residue resolution. Here, we review NMR techniques for such studies focusing on state-of-the-art tools and practical aspects. An efficient approach for determining the quaternary structure of multidomain complexes starts from the structures of individual domains or subunits. The arrangement of the domains/subunits within the complex is then defined based on NMR measurements that provide information about the domain interfaces combined with (long-range) distance and orientational restraints. Aspects discussed include sample preparation, specific isotope labeling and spin labeling; determination of binding interfaces and domain/subunit arrangements from chemical shift perturbations (CSP), nuclear Overhauser effects (NOEs), isotope editing/filtering, cross-saturation, and differential line broadening; and based on paramagnetic relaxation enhancements (PRE) using covalent and soluble spin labels. Finally, the utility of complementary methods such as small-angle X-ray or neutron scattering (SAXS, SANS), electron paramagnetic resonance (EPR) or fluorescence spectroscopy techniques is discussed. The applications of NMR techniques are illustrated with studies of challenging (high molecular weight) protein complexes.
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Affiliation(s)
- Christoph Göbl
- Biomolecular NMR and Center for Integrated Protein Science Munich at Department Chemie, Technische Universität München, Garching, Germany
| | - Tobias Madl
- Biomolecular NMR and Center for Integrated Protein Science Munich at Department Chemie, Technische Universität München, Garching, Germany; Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg, Germany; Institute of Molecular Biology, University of Graz, Graz, Austria.
| | - Bernd Simon
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Michael Sattler
- Biomolecular NMR and Center for Integrated Protein Science Munich at Department Chemie, Technische Universität München, Garching, Germany; Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg, Germany.
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19
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Abstract
Selenoproteins use the rare amino acid selenocysteine (Sec) to act as the first line of defense against oxidants, which are linked to aging, cancer, and neurodegenerative diseases. Many selenoproteins are oxidoreductases in which the reactive Sec is connected to a neighboring Cys and able to form a ring. These Sec-containing redox motifs govern much of the reactivity of selenoproteins. To study their fundamental properties, we have used (77)Se NMR spectroscopy in concert with theoretical calculations to determine the conformational preferences and mobility of representative motifs. This use of (77)Se as a probe enables the direct recording of the properties of Sec as its environment is systematically changed. We find that all motifs have several ring conformations in their oxidized state. These ring structures are most likely stabilized by weak, nonbonding interactions between the selenium and the amide carbon. To examine how the presence of selenium and ring geometric strain governs the motifs' reactivity, we measured the redox potentials of Sec-containing motifs and their corresponding Cys-only variants. The comparisons reveal that for C-terminal motifs the redox potentials increased between 20-25 mV when the selenenylsulfide bond was changed to a disulfide bond. Changes of similar magnitude arose when we varied ring size or the motifs' flanking residues. This suggests that the presence of Sec is not tied to unusually low redox potentials. The unique roles of selenoproteins in human health and their chemical reactivities may therefore not necessarily be explained by lower redox potentials, as has often been claimed.
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Schaefer-Ramadan S, Thorpe C, Rozovsky S. Site-specific insertion of selenium into the redox-active disulfide of the flavoprotein augmenter of liver regeneration. Arch Biochem Biophys 2014; 548:60-5. [PMID: 24582598 PMCID: PMC4009370 DOI: 10.1016/j.abb.2014.02.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 01/29/2014] [Accepted: 02/03/2014] [Indexed: 11/23/2022]
Abstract
Augmenter of liver regeneration (sfALR) is a small disulfide-bridged homodimeric flavoprotein with sulfhydryl oxidase activity. Here, we investigate the catalytic and spectroscopic consequences of selectively replacing C145 by a selenocysteine to complement earlier studies in which random substitution of ∼90% of the 6 cysteine residues per sfALR monomer was achieved growing Escherichia coli on selenite. A selenocysteine insertion sequence (SECIS) element was installed within the gene for human sfALR. SecALR2 showed a spectrum comparable to that of wild-type sfALR. The catalytic efficiency of SecALR2 towards dithiothreitol was 6.8-fold lower than a corresponding construct in which position 145 was returned to a cysteine residue while retaining the additional mutations introduced with the SECIS element. This all-cysteine control enzyme formed a mixed disulfide between C142 and β-mercaptoethanol releasing C145 to form a thiolate-flavin charge transfer absorbance band at ∼530nm. In contrast, SecALR2 showed a prominent long-wavelength absorbance at 585 nm consistent with the expectation that a selenolate would be a better charge-transfer donor to the isoalloxazine ring. These data show the robustness of the ALR protein fold towards the multiple mutations required to insert the SECIS element and provide the first example of a selenolate to flavin charge-transfer complex.
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Affiliation(s)
| | - Colin Thorpe
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, United States
| | - Sharon Rozovsky
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, United States.
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21
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Suzuki T, Makyio H, Ando H, Komura N, Menjo M, Yamada Y, Imamura A, Ishida H, Wakatsuki S, Kato R, Kiso M. Expanded potential of seleno-carbohydrates as a molecular tool for X-ray structural determination of a carbohydrate-protein complex with single/multi-wavelength anomalous dispersion phasing. Bioorg Med Chem 2014; 22:2090-101. [PMID: 24631362 DOI: 10.1016/j.bmc.2014.02.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 02/18/2014] [Indexed: 01/10/2023]
Abstract
Seleno-lactoses have been successfully synthesized as candidates for mimicking carbohydrate ligands for human galectin-9 N-terminal carbohydrate recognition domain (NCRD). Selenium was introduced into the mono- or di-saccharides using p-methylselenobenzoic anhydride (Tol2Se) as a novel selenating reagent. The TolSe-substituted monosaccharides were converted into selenoglycosyl donors or acceptors, which were reacted with coupling partners to afford seleno-lactoses. The seleno-lactoses were converted to the target compounds. The structure of human galectin-9 NCRD co-crystallized with 6-MeSe-lactose was determined with single/multi-wavelength anomalous dispersion (SAD/MAD) phasing and was similar to that of the co-crystal with natural lactose.
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Affiliation(s)
- Tatsuya Suzuki
- Department of Applied Bioorganic Chemistry, Gifu University, 1-1 Yanagido, Gifu-shi, Gifu 501-1193, Japan; Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Yoshida Ushinomiya-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Hisayoshi Makyio
- Structural Biology Research Center, Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
| | - Hiromune Ando
- Department of Applied Bioorganic Chemistry, Gifu University, 1-1 Yanagido, Gifu-shi, Gifu 501-1193, Japan; Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Yoshida Ushinomiya-cho, Sakyo-ku, Kyoto 606-8501, Japan.
| | - Naoko Komura
- Department of Applied Bioorganic Chemistry, Gifu University, 1-1 Yanagido, Gifu-shi, Gifu 501-1193, Japan; Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Yoshida Ushinomiya-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Masanori Menjo
- Department of Applied Bioorganic Chemistry, Gifu University, 1-1 Yanagido, Gifu-shi, Gifu 501-1193, Japan
| | - Yusuke Yamada
- Structural Biology Research Center, Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
| | - Akihiro Imamura
- Department of Applied Bioorganic Chemistry, Gifu University, 1-1 Yanagido, Gifu-shi, Gifu 501-1193, Japan
| | - Hideharu Ishida
- Department of Applied Bioorganic Chemistry, Gifu University, 1-1 Yanagido, Gifu-shi, Gifu 501-1193, Japan
| | - Soichi Wakatsuki
- Structural Biology Research Center, Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan; Photon Science, SLAC Natl. Accelerator Laboratory Structure Science, 2575 Sand Hill Road, MS 69, Menlo Park, CA 94025-7015, USA; Department of Structural Biology, Stanford University, Beckman Center B105, 279 Campus Drive, Stanford, CA 94305-5126, USA
| | - Ryuichi Kato
- Structural Biology Research Center, Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
| | - Makoto Kiso
- Department of Applied Bioorganic Chemistry, Gifu University, 1-1 Yanagido, Gifu-shi, Gifu 501-1193, Japan; Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Yoshida Ushinomiya-cho, Sakyo-ku, Kyoto 606-8501, Japan
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22
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23
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Klint JK, Senff S, Saez NJ, Seshadri R, Lau HY, Bende NS, Undheim EAB, Rash LD, Mobli M, King GF. Production of recombinant disulfide-rich venom peptides for structural and functional analysis via expression in the periplasm of E. coli. PLoS One 2013; 8:e63865. [PMID: 23667680 PMCID: PMC3646780 DOI: 10.1371/journal.pone.0063865] [Citation(s) in RCA: 123] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 04/06/2013] [Indexed: 11/27/2022] Open
Abstract
Disulfide-rich peptides are the dominant component of most animal venoms. These peptides have received much attention as leads for the development of novel therapeutic agents and bioinsecticides because they target a wide range of neuronal receptors and ion channels with a high degree of potency and selectivity. In addition, their rigid disulfide framework makes them particularly well suited for addressing the crucial issue of in vivo stability. Structural and functional characterization of these peptides necessitates the development of a robust, reliable expression system that maintains their native disulfide framework. The bacterium Escherichia coli has long been used for economical production of recombinant proteins. However, the expression of functional disulfide-rich proteins in the reducing environment of the E. coli cytoplasm presents a significant challenge. Thus, we present here an optimised protocol for the expression of disulfide-rich venom peptides in the periplasm of E. coli, which is where the endogenous machinery for production of disulfide-bonds is located. The parameters that have been investigated include choice of media, induction conditions, lysis methods, methods of fusion protein and peptide purification, and sample preparation for NMR studies. After each section a recommendation is made for conditions to use. We demonstrate the use of this method for the production of venom peptides ranging in size from 2 to 8 kDa and containing 2-6 disulfide bonds.
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Affiliation(s)
- Julie K. Klint
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Sebastian Senff
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Natalie J. Saez
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Radha Seshadri
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Ho Yee Lau
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Niraj S. Bende
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Eivind A. B. Undheim
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Lachlan D. Rash
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Mehdi Mobli
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Glenn F. King
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
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24
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Hydrogen bond strengths in phosphorylated and sulfated amino acid residues. PLoS One 2013; 8:e57804. [PMID: 23472106 PMCID: PMC3589483 DOI: 10.1371/journal.pone.0057804] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2012] [Accepted: 01/24/2013] [Indexed: 11/29/2022] Open
Abstract
Post-translational modification by the addition of an oxoanion functional group, usually a phosphate group and less commonly a sulfate group, leads to diverse structural and functional consequences in protein systems. Building upon previous studies of the phosphoserine residue (pSer), we address the distinct nature of hydrogen bonding interactions in phosphotyrosine (pTyr) and sulfotyrosine (sTyr) residues. We derive partial charges for these modified residues and then study them in the context of molecular dynamics simulation of model tripeptides and sulfated protein complexes, potentials of mean force for interacting residue pairs, and a survey of the interactions of modified residues among experimental protein structures. Overall, our findings show that for pTyr, bidentate interactions with Arg are particularly dominant, as has been previously demonstrated for pSer. sTyr interactions with Arg are significantly weaker, even as compared to the same interactions made by the Glu residue. Our work sheds light on the distinct nature of these modified tyrosine residues, and provides a physical-chemical foundation for future studies with the goal of understanding their roles in systems of biological interest.
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