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Wei M, Liao H, Li Q, Deng X, Gao C, Ding N, Sun W, Zhu H, Guo J, Chen C, Zhang Y. Ergosterols with rare peroxide, oxetane ring moiety, and a lactone ring from Aspergillus spectabilis and their immunosuppressive activities. PHYTOCHEMISTRY 2024; 222:114070. [PMID: 38574957 DOI: 10.1016/j.phytochem.2024.114070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 02/27/2024] [Accepted: 03/25/2024] [Indexed: 04/06/2024]
Abstract
Ten ergostane-type steroids, including seven undescribed ones named spectasteroids A-G, were obtained from Aspergillus spectabilis. Their structures and absolute configurations were determined based on HRESIMS, NMR, ECD calculations, and single-crystal X-ray diffraction analyses. Structurally, spectasteroid A was a unique example of aromatic ergostane-type steroid that featured a rare peroxide ring moiety; spectasteroid B contained a rare oxetane ring system formed between C-9 and C-14; and spectasteroid C was an unusual 3,4-seco-ergostane steroid with an extra lactone ring between C-3 and C-9. Spectasteroids F and G specifically showed inhibitory effects against concanavalin A-induced T lymphocyte proliferation and lipopolysaccharide-induced B lymphocyte proliferation, with IC50 values ranging from 2.33 to 4.22 μM. Spectasteroid F also showed excellent antimultidrug resistance activity, which remarkable enhanced the inhibitory activity of PTX on the colony formation of SW620/Ad300 cells.
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Affiliation(s)
- Mengsha Wei
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Hong Liao
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Qin Li
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Xueying Deng
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Chi Gao
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Nanjin Ding
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Weiguang Sun
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Hucheng Zhu
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Jieru Guo
- Tongji Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
| | - Chunmei Chen
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
| | - Yonghui Zhang
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
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Seneviratne AMPB, Burroughs M, Giralt E, Smrcka AV. Direct-reversible binding of small molecules to G protein βγ subunits. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2011; 1814:1210-8. [PMID: 21621014 DOI: 10.1016/j.bbapap.2011.05.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Revised: 05/10/2011] [Accepted: 05/11/2011] [Indexed: 02/08/2023]
Abstract
Heterotrimeric guanine nucleotide-binding proteins (G proteins) composed of three subunits α, β, γ mediate activation of multiple intracellular signaling cascades initiated by G protein-coupled receptors (GPCRs). Previously our laboratory identified small molecules that bind to Gβγ and interfere with or enhance binding of select effectors with Gβγ. To understand the molecular mechanisms of selectivity and assess binding of compounds to Gβγ, we used biophysical and biochemical approaches to directly monitor small molecule binding to Gβγ. Surface plasmon resonance (SPR) analysis indicated that multiple compounds bound directly to Gβγ with affinities in the high nanomolar to low micromolar range but with surprisingly slow on and off rate kinetics. While the k(off) was slow for most of the compounds in physiological buffers, they could be removed from Gβγ with mild chaotropic salts or mildly dissociating collision energy in a mass-spectrometer indicating that compound-Gβγ interactions were non-covalent. Finally, at concentrations used to observe maximal biological effects the stoichiometry of binding was 1:1. The results from this study show that small molecule modulation of Gβγ-effector interactions is by specific direct non-covalent and reversible binding of small molecules to Gβγ. This is highly relevant to development of Gβγ targeting as a therapeutic approach since reversible, direct binding is a prerequisite for drug development and important for specificity.
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Balla T. Green light to illuminate signal transduction events. Trends Cell Biol 2009; 19:575-86. [PMID: 19818623 DOI: 10.1016/j.tcb.2009.08.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2009] [Revised: 08/03/2009] [Accepted: 08/11/2009] [Indexed: 11/17/2022]
Abstract
When cells are exposed to hormones that act on cell surface receptors, information is processed through the plasma membrane into the cell interior via second messengers generated in the inner leaflet of the plasma membrane. Individual biochemical steps along this cascade have been characterized from ligand binding to receptors through to activation of guanine nucleotide binding proteins and their downstream effectors such as adenylate cyclase or phospholipase C. However, the complexity of temporal and spatial integration of these molecular events requires that they are studied in intact cells. The great expansion of fluorescent techniques and improved imaging technologies such as confocal and TIRF microscopy combined with genetically-engineered protein modules has provided a completely new approach to signal transduction research. Spatial definition of biochemical events followed with real-time temporal resolution has become a standard goal, and several new techniques are now breaking the resolution barrier of light microscopy.
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Affiliation(s)
- Tamas Balla
- Section on Molecular Signal Transduction, Program on Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
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Helmholz H, Naatz S, Lassen S, Prange A. Isolation of a cytotoxic glycoprotein from the Scyphozoa Cyanea lamarckii by lectin-affinity chromatography and characterization of molecule interactions by surface plasmon resonance. J Chromatogr B Analyt Technol Biomed Life Sci 2008; 871:60-6. [DOI: 10.1016/j.jchromb.2008.06.040] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2007] [Revised: 06/06/2008] [Accepted: 06/23/2008] [Indexed: 11/26/2022]
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Millward SW, Fiacco S, Austin RJ, Roberts RW. Design of cyclic peptides that bind protein surfaces with antibody-like affinity. ACS Chem Biol 2007; 2:625-34. [PMID: 17894440 PMCID: PMC3747972 DOI: 10.1021/cb7001126] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
There is a pressing need for new molecular tools to target protein surfaces with high affinity and specificity. Here, we describe cyclic messenger RNA display with a trillion-member covalent peptide macrocycle library. Using this library, we have designed a number of high-affinity, redox-insensitive, cyclic peptides that target the signaling protein G alpha i1. In addition to cyclization, our library construction took advantage of an expanded genetic code, utilizing nonsense suppression to insert N-methylphenylalanine as a 21st amino acid. The designed macrocycles exhibit several intriguing features. First, the core motif seen in all of the selected variants is the same and shares an identical context with respect to the macrocyclic scaffold, consistent with the idea that selection simultaneously optimizes both the cyclization chemistry and the structural placement of the binding epitope. Second, detailed characterization of one molecule, cyclic G alpha i binding peptide (cycGiBP), demonstrates substantially enhanced proteolytic stability relative to that of the parent linear molecule. Third and perhaps most important, the cycGiBP peptide binds the target with very high affinity ( K i approximately 2.1 nM), similar to those of many of the best monoclonal antibodies and higher than that of the betagamma heterodimer, an endogenous G alpha i1 ligand. Overall the work provides a general route to design novel, low-molecular-weight, high-affinity ligands that target protein surfaces.
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Affiliation(s)
- Steven W. Millward
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125
| | - Stephen Fiacco
- Department of Chemistry, Chemical Engineering, and Biology, University of Southern California, 3710 McClintock Avenue, Los Angeles, California 90089-1211
| | - Ryan J. Austin
- Department of Chemistry, Chemical Engineering, and Biology, University of Southern California, 3710 McClintock Avenue, Los Angeles, California 90089-1211
| | - Richard W. Roberts
- Department of Chemistry, Chemical Engineering, and Biology, University of Southern California, 3710 McClintock Avenue, Los Angeles, California 90089-1211
- Corresponding author,
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Minic J, Grosclaude J, Aioun J, Persuy MA, Gorojankina T, Salesse R, Pajot-Augy E, Hou Y, Helali S, Jaffrezic-Renault N, Bessueille F, Errachid A, Gomila G, Ruiz O, Samitier J. Immobilization of native membrane-bound rhodopsin on biosensor surfaces. Biochim Biophys Acta Gen Subj 2005; 1724:324-32. [PMID: 15927400 DOI: 10.1016/j.bbagen.2005.04.017] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2005] [Revised: 04/12/2005] [Accepted: 04/13/2005] [Indexed: 11/16/2022]
Abstract
In this paper, we evaluated the grafting of G-protein-coupled receptors (GPCRs) onto functionalized surfaces, which is a primary requirement to elaborate receptor-based biosensors, or to develop novel GPCR assays. Bovine rhodopsin, a prototypical GPCR, was used in the form of receptor-enriched membrane fraction. Quantitative immobilization of the membrane-bound rhodopsin either non-specifically on a carboxylated dextran surface grafted with long alkyl groups, or specifically on a surface coated with anti-rhodopsin antibody was demonstrated by surface plasmon resonance. In addition, a new substrate based on mixed self-assembled multilayer that anchors specific anti-receptor antibodies was developed. Electrochemical impedance spectroscopy performed upon deposition of membrane-bound rhodopsin of increasing concentration exhibited a significant change, until a saturation level was reached, indicating optimum receptor immobilization on the substrate. The structures obtained with this new immobilization procedure of the rhodopsin in its native membrane environment are stable, with a controlled density of specific anchoring sites. Therefore, such receptor immobilization method is attractive for a range of applications, especially in the field of GPCR biosensors.
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Affiliation(s)
- Jasmina Minic
- INRA, Neurobiologie de l'Olfaction et de la Prise Alimentaire, Equipe Récepteurs et Communication Chimique, Domaine de Vilvert, 78352 Jouy-en-Josas Cedex, France
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Rich RL, Myszka DG. A survey of the year 2002 commercial optical biosensor literature. J Mol Recognit 2004; 16:351-82. [PMID: 14732928 DOI: 10.1002/jmr.649] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We have compiled 819 articles published in the year 2002 that involved commercial optical biosensor technology. The literature demonstrates that the technology's application continues to increase as biosensors are contributing to diverse scientific fields and are used to examine interactions ranging in size from small molecules to whole cells. Also, the variety of available commercial biosensor platforms is increasing and the expertise of users is improving. In this review, we use the literature to focus on the basic types of biosensor experiments, including kinetics, equilibrium analysis, solution competition, active concentration determination and screening. In addition, using examples of particularly well-performed analyses, we illustrate the high information content available in the primary response data and emphasize the impact of including figures in publications to support the results of biosensor analyses.
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Affiliation(s)
- Rebecca L Rich
- Center for Biomolecular Interaction Analysis, University of Utah, Salt Lake City, UT 84132, USA
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Svitel J, Balbo A, Mariuzza RA, Gonzales NR, Schuck P. Combined affinity and rate constant distributions of ligand populations from experimental surface binding kinetics and equilibria. Biophys J 2003; 84:4062-77. [PMID: 12770910 PMCID: PMC1302986 DOI: 10.1016/s0006-3495(03)75132-7] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2002] [Accepted: 02/21/2003] [Indexed: 10/21/2022] Open
Abstract
The present article considers the influence of heterogeneity in a mobile analyte or in an immobilized ligand population on the surface binding kinetics and equilibrium isotherms. We describe strategies for solving the inverse problem of calculating two-dimensional distributions of rate and affinity constants from experimental data on surface binding kinetics, such as obtained from optical biosensors. Although the characterization of a heterogeneous population of analytes binding to uniform surface sites may be possible under suitable experimental conditions, computational difficulties currently limit this approach. In contrast, the case of uniform analytes binding to heterogeneous populations of surface sites is computationally feasible, and can be combined with Tikhonov-Phillips and maximum entropy regularization techniques that provide the simplest distribution that is consistent with the data. The properties of this ligand distribution analysis are explored with several experimental and simulated data sets. The resulting two-dimensional rate and affinity constant distributions can describe well experimental kinetic traces measured with optical biosensors. The use of kinetic surface binding data can give significantly higher resolution than affinity distributions from the binding isotherms alone. The shape and the level of detail of the calculated distributions depend on the experimental conditions, such as contact times and the concentration range of the analyte. Despite the flexibility introduced by considering surface site distributions, the impostor application of this model to surface binding data from transport limited binding processes or from analyte distributions can be identified by large residuals, if a sufficient range of analyte concentrations and contact times are used. The distribution analysis can provide a rational interpretation of complex experimental surface binding kinetics, and provides an analytical tool for probing the homogeneity of the populations of immobilized protein.
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Affiliation(s)
- Juraj Svitel
- Division of Bioengineering & Physical Science, ORS, Office of the Director, National Institutes of Health, Bethesda, Maryland 20892, USA
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