1
|
Hanashima S, Yano Y, Murata M. Enantiomers of phospholipids and cholesterol: A key to decipher lipid‐lipid interplay in membrane. Chirality 2020; 32:282-298. [DOI: 10.1002/chir.23171] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Revised: 12/23/2019] [Accepted: 12/26/2019] [Indexed: 12/13/2022]
Affiliation(s)
- Shinya Hanashima
- Department of Chemistry, Graduate School of ScienceOsaka University Toyonaka Japan
| | - Yo Yano
- Department of Chemistry, Graduate School of ScienceOsaka University Toyonaka Japan
| | - Michio Murata
- Department of Chemistry, Graduate School of ScienceOsaka University Toyonaka Japan
| |
Collapse
|
2
|
Abstract
Cholesterol is a key steroidal, lipid biomolecule found abundantly in plasma membranes of eukaryotic cells. It is an important structural component of cellular membranes and regulates membrane fluidity and permeability. Cholesterol is also essential for normal functioning of key proteins including ion-channels, G protein-coupled receptors (GPCRs), membrane bound steroid receptors, and receptor kinases. It is thought that cholesterol exerts its actions via specific binding to chiral proteins and lipids as well as through non-specific physiochemical interactions. Distinguishing between the specific and the non-specific interactions can be difficult. Although much remains unclear, progress has been made in recent years by utilizing ent-cholesterol, the enantiomer of natural cholesterol (nat-cholesterol) as a probe. Ent-Cholesterol is the non-superimposable mirror image of nat-cholesterol and exhibits identical physiochemical properties as nat-cholesterol. Hence, if the biological effects of cholesterol result solely due to membrane effects, it is expected that there will be no difference between ent-cholesterol and nat-cholesterol. However, when direct binding with chiral proteins and lipids is involved, the enantiomer is expected to potentially elicit significantly different, measurable effects due to formation of diastereomeric complexes. In this chapter, we have reviewed the literature related to ent-cholesterol and its use as a probe for various biophysical and biological interactions of cholesterol.
Collapse
|
3
|
A biocatalytic hydroxylation-enabled unified approach to C19-hydroxylated steroids. Nat Commun 2019; 10:3378. [PMID: 31358750 PMCID: PMC6662754 DOI: 10.1038/s41467-019-11344-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Accepted: 07/10/2019] [Indexed: 11/11/2022] Open
Abstract
Steroidal C19-hydroxylation is pivotal to the synthesis of naturally occurring bioactive C19-OH steroids and 19-norsteroidal pharmaceuticals. However, realizing this transformation is proved to be challenging through either chemical or biological synthesis. Herein, we report a highly efficient method to synthesize 19-OH-cortexolone in 80% efficiency at the multi-gram scale. The obtained C19-OH-cortexolone can be readily transformed to various synthetically useful intermediates including the industrially valuable 19-OH-androstenedione, which can serve as a basis for synthesis of C19-functionalized steroids as well as 19-nor steroidal drugs. Using this biocatalytic C19-hydroxylation method, the unified synthesis of six C19-hydroxylated pregnanes is achieved in just 4 to 9 steps. In addition, the structure of sclerosteroid B is revised on the basis of our synthesis. C19 hydroxylation is a unique feature of some bioactive steroids. Here, the authors developed a direct C19 hydroxylation approach to scalably access 19-OH-cortexolone in the host T. cucumeris and then converted the product into various pharmaceutically useful products via chemical synthesis.
Collapse
|
4
|
Enkavi G, Javanainen M, Kulig W, Róg T, Vattulainen I. Multiscale Simulations of Biological Membranes: The Challenge To Understand Biological Phenomena in a Living Substance. Chem Rev 2019; 119:5607-5774. [PMID: 30859819 PMCID: PMC6727218 DOI: 10.1021/acs.chemrev.8b00538] [Citation(s) in RCA: 184] [Impact Index Per Article: 36.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Indexed: 12/23/2022]
Abstract
Biological membranes are tricky to investigate. They are complex in terms of molecular composition and structure, functional over a wide range of time scales, and characterized by nonequilibrium conditions. Because of all of these features, simulations are a great technique to study biomembrane behavior. A significant part of the functional processes in biological membranes takes place at the molecular level; thus computer simulations are the method of choice to explore how their properties emerge from specific molecular features and how the interplay among the numerous molecules gives rise to function over spatial and time scales larger than the molecular ones. In this review, we focus on this broad theme. We discuss the current state-of-the-art of biomembrane simulations that, until now, have largely focused on a rather narrow picture of the complexity of the membranes. Given this, we also discuss the challenges that we should unravel in the foreseeable future. Numerous features such as the actin-cytoskeleton network, the glycocalyx network, and nonequilibrium transport under ATP-driven conditions have so far received very little attention; however, the potential of simulations to solve them would be exceptionally high. A major milestone for this research would be that one day we could say that computer simulations genuinely research biological membranes, not just lipid bilayers.
Collapse
Affiliation(s)
- Giray Enkavi
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| | - Matti Javanainen
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
- Institute
of Organic Chemistry and Biochemistry of the Czech Academy
of Sciences, Flemingovo naḿesti 542/2, 16610 Prague, Czech Republic
- Computational
Physics Laboratory, Tampere University, P.O. Box 692, FI-33014 Tampere, Finland
| | - Waldemar Kulig
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| | - Tomasz Róg
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
- Computational
Physics Laboratory, Tampere University, P.O. Box 692, FI-33014 Tampere, Finland
| | - Ilpo Vattulainen
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
- Computational
Physics Laboratory, Tampere University, P.O. Box 692, FI-33014 Tampere, Finland
- MEMPHYS-Center
for Biomembrane Physics
| |
Collapse
|
5
|
Deng L, Jin L, Dong G. Fused-Ring Formation by an Intramolecular "Cut-and-Sew" Reaction between Cyclobutanones and Alkynes. Angew Chem Int Ed Engl 2018; 57:2702-2706. [PMID: 29338109 PMCID: PMC5849476 DOI: 10.1002/anie.201712487] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 01/03/2017] [Indexed: 11/10/2022]
Abstract
The development of a catalytic intramolecular "cut-and-sew" transformation between cyclobutanones and alkynes to construct cyclohexenone-fused rings is described herein. The challenge arises from the need for selective coupling at the more sterically hindered proximal position, and can be addressed by using an electron-rich, but less bulky, phosphine ligand. The control experiment and 13 C-labelling study suggest that the reaction may start with cleavage of the less hindered distal C-C bond of cyclobutanones, followed by decarbonylation and CO reinsertion to enable Rh insertion at the more hindered proximal position.
Collapse
Affiliation(s)
- Lin Deng
- Department of Chemistry, University of Chicago, Chicago, IL, 60637, USA
| | - Likun Jin
- Department of Chemistry, University of Chicago, Chicago, IL, 60637, USA
- College of Chemical Engineering, Nanjing University of Science & Technology, Nanjing, 210094, P. R. China
| | - Guangbin Dong
- Department of Chemistry, University of Chicago, Chicago, IL, 60637, USA
| |
Collapse
|
6
|
Deng L, Jin L, Dong G. Fused-Ring Formation by an Intramolecular “Cut-and-Sew” Reaction between Cyclobutanones and Alkynes. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201712487] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Lin Deng
- Department of Chemistry; University of Chicago; Chicago IL 60637 USA
| | - Likun Jin
- Department of Chemistry; University of Chicago; Chicago IL 60637 USA
- College of Chemical Engineering; Nanjing University of Science & Technology; Nanjing 210094 P. R. China
| | - Guangbin Dong
- Department of Chemistry; University of Chicago; Chicago IL 60637 USA
| |
Collapse
|
7
|
Sayyad AA, Kaliappan KP. Sequential Enyne-Metathesis/Diels-Alder Strategy: Rapid Access to Sugar-Oxasteroid-Quinone Hybrids. European J Org Chem 2017. [DOI: 10.1002/ejoc.201700599] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Ashik A. Sayyad
- Department of Chemistry; Indian Institute of Technology Bombay; 400076 Mumbai India
| | - Krishna P. Kaliappan
- Department of Chemistry; Indian Institute of Technology Bombay; 400076 Mumbai India
| |
Collapse
|
8
|
Brownholland DP, Covey DF. Synthesis of side-chain oxysterols and their enantiomers through cross-metathesis reactions of Δ 22 steroids. Steroids 2017; 121:22-31. [PMID: 28300584 PMCID: PMC5398201 DOI: 10.1016/j.steroids.2017.03.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 03/02/2017] [Accepted: 03/09/2017] [Indexed: 10/20/2022]
Abstract
A synthetic route that utilizes a cross-metathesis reaction with Δ22 steroids has been developed to prepare sterols with varying C-27 side-chains. Natural sterols containing hydroxyl groups at the 25 and (25R)-26 positions were prepared. Enantiomers of cholesterol and (3β,25R)-26-hydroxycholesterol (27-hydroxycholesterol) trideuterated at C-19 were prepared for future biological studies.
Collapse
Affiliation(s)
- David P Brownholland
- Department of Chemistry, Carthage College, 2001 Alford Park, Kenosha, WI 53140, USA.
| | - Douglas F Covey
- Department of Developmental Biology, Washington University in St. Louis, 660 South Euclid Avenue, St. Louis, MO 63110, USA; Department of Anesthesiology, Washington University in St. Louis, 660 South Euclid Avenue, St. Louis, MO 63110, USA; Department of Psychiatry, Washington University in St. Louis, 660 South Euclid Avenue, St. Louis, MO 63110, USA.
| |
Collapse
|
9
|
Luchetti G, Sircar R, Kong JH, Nachtergaele S, Sagner A, Byrne EFX, Covey DF, Siebold C, Rohatgi R. Cholesterol activates the G-protein coupled receptor Smoothened to promote Hedgehog signaling. eLife 2016; 5:e20304. [PMID: 27705744 PMCID: PMC5123864 DOI: 10.7554/elife.20304] [Citation(s) in RCA: 174] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 10/03/2016] [Indexed: 12/12/2022] Open
Abstract
Cholesterol is necessary for the function of many G-protein coupled receptors (GPCRs). We find that cholesterol is not just necessary but also sufficient to activate signaling by the Hedgehog (Hh) pathway, a prominent cell-cell communication system in development. Cholesterol influences Hh signaling by directly activating Smoothened (SMO), an orphan GPCR that transmits the Hh signal across the membrane in all animals. Unlike many GPCRs, which are regulated by cholesterol through their heptahelical transmembrane domains, SMO is activated by cholesterol through its extracellular cysteine-rich domain (CRD). Residues shown to mediate cholesterol binding to the CRD in a recent structural analysis also dictate SMO activation, both in response to cholesterol and to native Hh ligands. Our results show that cholesterol can initiate signaling from the cell surface by engaging the extracellular domain of a GPCR and suggest that SMO activity may be regulated by local changes in cholesterol abundance or accessibility.
Collapse
Affiliation(s)
- Giovanni Luchetti
- Department of Biochemistry, Stanford University School of Medicine, Stanford, United States
- Department of Medicine, Stanford University School of Medicine, Stanford, United States
| | - Ria Sircar
- Department of Biochemistry, Stanford University School of Medicine, Stanford, United States
- Department of Medicine, Stanford University School of Medicine, Stanford, United States
| | - Jennifer H Kong
- Department of Biochemistry, Stanford University School of Medicine, Stanford, United States
- Department of Medicine, Stanford University School of Medicine, Stanford, United States
| | - Sigrid Nachtergaele
- Department of Biochemistry, Stanford University School of Medicine, Stanford, United States
- Department of Medicine, Stanford University School of Medicine, Stanford, United States
| | - Andreas Sagner
- Mill Hill Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Eamon FX Byrne
- Division of Structural Biology, University of Oxford, Oxford, United Kingdom
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Douglas F Covey
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, United States
| | - Christian Siebold
- Division of Structural Biology, University of Oxford, Oxford, United Kingdom
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Rajat Rohatgi
- Department of Biochemistry, Stanford University School of Medicine, Stanford, United States
- Department of Medicine, Stanford University School of Medicine, Stanford, United States
| |
Collapse
|
10
|
Kepczynski M, Róg T. Functionalized lipids and surfactants for specific applications. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:2362-2379. [PMID: 26946243 DOI: 10.1016/j.bbamem.2016.02.038] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 02/23/2016] [Accepted: 02/25/2016] [Indexed: 12/17/2022]
Abstract
Synthetic lipids and surfactants that do not exist in biological systems have been used for the last few decades in both basic and applied science. The most notable applications for synthetic lipids and surfactants are drug delivery, gene transfection, as reporting molecules, and as support for structural lipid biology. In this review, we describe the potential of the synergistic combination of computational and experimental methodologies to study the behavior of synthetic lipids and surfactants embedded in lipid membranes and liposomes. We focused on select cases in which molecular dynamics simulations were used to complement experimental studies aiming to understand the structure and properties of new compounds at the atomistic level. We also describe cases in which molecular dynamics simulations were used to design new synthetic lipids and surfactants, as well as emerging fields for the application of these compounds. This article is part of a Special Issue entitled: Biosimulations edited by Ilpo Vattulainen and Tomasz Róg.
Collapse
Affiliation(s)
- Mariusz Kepczynski
- Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków, Poland.
| | - Tomasz Róg
- Department of Physics, Tampere University of Technology, P.O. Box 692, FI-33101, Tampere, Finland; Department of Physics, Helsinki University, P.O. Box 64, FI 00014 Helsinki, Finland.
| |
Collapse
|
11
|
Affiliation(s)
- Keith P. Reber
- Department of Chemistry and
Biochemistry, University of California, San Diego, 9500 Gilman
Drive, La Jolla, California 92093-0358, United States
| | - Jing Xu
- Department of Chemistry and
Biochemistry, University of California, San Diego, 9500 Gilman
Drive, La Jolla, California 92093-0358, United States
| | - Carlos A. Guerrero
- Department of Chemistry and
Biochemistry, University of California, San Diego, 9500 Gilman
Drive, La Jolla, California 92093-0358, United States
| |
Collapse
|
12
|
Zhou NJ, Geng CA, Huang XY, Ma YB, Zhang XM, Wang JL, Chen JJ. Anti-hepatitis B virus active constituents from Swertia chirayita. Fitoterapia 2014; 100:27-34. [PMID: 25447162 DOI: 10.1016/j.fitote.2014.11.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 11/10/2014] [Accepted: 11/12/2014] [Indexed: 02/07/2023]
Abstract
Four new compounds swertiachiralatone A (1), swertiachoside A (2), swertiachirdiol A (3) and swertiachoside B (4), together with twenty-six known ones were isolated from the ethanol extract of Swertia chirayita. Their structures were elucidated by extensive spectroscopic analyses (1D- and 2D-NMR, HRESIMS, UV, IR and [α]D). All compounds were evaluated for anti-hepatitis B virus (anti-HBV) activities on HepG 2.2.15 cells line in vitro, of which compounds 14 and 19 showed inhibitory activity on hepatitis B surface antigen (HBsAg) secretion with IC50 values of 0.31 ± 0.045 and 1.49 ± 0.033 mM; compounds 14 and 28 exhibited activity against hepatitis B e antigen (HBeAg) secretion with IC50 values of 0.77 ± 0.076 and 5.92 ± 1.02 mM; and eight compounds (8,9,13,14,24-26,29) possessed activity against HBV DNA replication with IC50 values of 0.07-0.33 mM. In particular (+)-cycloolivil-4'-O-β-d-glucopyranoside (14) exhibited inhibition not only on the secretions of HBsAg and HBeAg with IC50 values of 0.31 ± 0.045 mM (SI=4.29) and 0.77 ± 0.076 mM (SI=1.75), respectively, but also on HBV DNA replication with an IC50 value of 0.29 ± 0.034 mM (SI=4.66).
Collapse
Affiliation(s)
- Ning-Jia Zhou
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Chang-An Geng
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, PR China
| | - Xiao-Yan Huang
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, PR China
| | - Yun-Bao Ma
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, PR China
| | - Xue-Mei Zhang
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, PR China
| | - Ju-Le Wang
- Medical School of Tibet University, Lhasa 850000, PR China
| | - Ji-Jun Chen
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, PR China.
| |
Collapse
|
13
|
Bandari S, Chakraborty H, Covey DF, Chattopadhyay A. Membrane dipole potential is sensitive to cholesterol stereospecificity: implications for receptor function. Chem Phys Lipids 2014; 184:25-9. [PMID: 25219773 DOI: 10.1016/j.chemphyslip.2014.09.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 09/05/2014] [Accepted: 09/08/2014] [Indexed: 12/25/2022]
Abstract
Dipole potential is the potential difference within the membrane bilayer, which originates due to the nonrandom arrangement of lipid dipoles and water molecules at the membrane interface. Cholesterol, an essential lipid in higher eukaryotic membranes, has previously been shown to increase membrane dipole potential. In this work, we explored the effect of stereoisomers of cholesterol, ent-cholesterol and epi-cholesterol, on membrane dipole potential, monitored by the dual wavelength ratiometric approach utilizing the probe di-8-ANEPPS. Our results show that cholesterol and ent-cholesterol share comparable ability in increasing membrane dipole potential. In contrast, epi-cholesterol displays a slight reduction in membrane dipole potential. Our results constitute the first report on the effect of stereoisomers of cholesterol on membrane dipole potential, and imply that an extremely subtle change in sterol structure can significantly alter the dipolar field at the membrane interface. These results assume relevance in the context of differential abilities of these stereoisomers of cholesterol in supporting the activity of the serotonin1A receptor, a representative G protein-coupled receptor. The close correlation between membrane dipole potential and receptor activity provides new insight in receptor-cholesterol interaction in terms of stereospecificity. We envision that membrane dipole potential could prove to be a sensitive indicator of lipid-protein interactions in biological membranes.
Collapse
Affiliation(s)
- Suman Bandari
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
| | - Hirak Chakraborty
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
| | - Douglas F Covey
- Departments of Developmental Biology, Anesthesiology, Psychiatry and The Taylor Family Institute for Innovative Psychiatry Research, WA University in St. Louis Medical School, St. Louis, MO 63110, USA
| | | |
Collapse
|
14
|
Mydock-McGrane L, Rath NP, Covey DF. Synthesis of a smoothened cholesterol: 18,19-di-nor-cholesterol. J Org Chem 2014; 79:5636-43. [PMID: 24823889 PMCID: PMC4076041 DOI: 10.1021/jo500813n] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Indexed: 11/29/2022]
Abstract
Herein, we report the first synthesis of a demethylated form of cholesterol (18,19-di-nor-cholesterol), in which the C18 and C19 methyl groups of the β-face were eliminated. Recent molecular simulations modeling 18,19-di-nor-cholesterol have suggested that cholesterol's opposing rough β-face and smooth α-face play necessary roles in cholesterol's membrane condensing abilities and, additionally, that specific facial preferences are displayed as cholesterol interacts with different neighboring lipids and transmembrane proteins. Inspired by these poorly characterized biochemical interactions, an extensive 18-step synthesis was completed as part of a collaborative effort, wherein synthesizing a "smoothened" cholesterol analogue would provide a direct way to experimentally measure the significance of the β-face methyl groups. Starting from known perhydrochrysenone A, the synthesis of 18,19-di-nor-cholesterol was accomplished with an excellent overall yield of 3.5%. The use of the highly stereoselective Dieckmann condensation and the employment of Evans' chiral auxiliary were both key to ensuring the success of this synthesis.
Collapse
Affiliation(s)
- Laurel Mydock-McGrane
- Department
of Developmental Biology, Anesthesiology, and Psychiatry, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Nigam P. Rath
- Department
of Chemistry and Biochemistry, University
of Missouri−St. Louis, St. Louis, Missouri 63121, United States
| | - Douglas F. Covey
- Department
of Developmental Biology, Anesthesiology, and Psychiatry, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| |
Collapse
|
15
|
Jafurulla M, Rao BD, Sreedevi S, Ruysschaert JM, Covey DF, Chattopadhyay A. Stereospecific requirement of cholesterol in the function of the serotonin1A receptor. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:158-63. [PMID: 24008092 DOI: 10.1016/j.bbamem.2013.08.015] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Revised: 08/16/2013] [Accepted: 08/23/2013] [Indexed: 01/04/2023]
Abstract
The serotonin1A receptor is an important member of the G protein-coupled receptor (GPCR) family. It is involved in the generation and modulation of a variety of cognitive and behavioral functions and serves as a drug target. Previous work from our laboratory has established the sensitivity of the function of the serotonin1A receptor to membrane cholesterol. Solubilization of the hippocampal serotonin1A receptor utilizing the zwitterionic detergent CHAPS is accompanied by loss of cholesterol and results in reduction in specific ligand binding. Replenishment of cholesterol to solubilized membranes restores specific ligand binding to the receptor. We utilized this strategy of sterol replenishment of solubilized membranes to explore the stereospecific stringency of cholesterol for receptor function. We used two stereoisomers of cholesterol, ent-cholesterol (enantiomer of cholesterol) and epi-cholesterol (a diastereomer of cholesterol), for this purpose. Importantly, we show here that while ent-cholesterol could replace cholesterol in supporting receptor function, epi-cholesterol could not. These results imply that the requirement of membrane cholesterol for the serotonin1A receptor function is diastereospecific, yet not enantiospecific. Our results extend and help define specificity of the interaction of membrane cholesterol with the serotonin1A receptor, and represent the first report utilizing ent-cholesterol to examine stereospecificity of GPCR-cholesterol interaction.
Collapse
Affiliation(s)
- Md Jafurulla
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad 500 007, India
| | | | | | | | | | | |
Collapse
|
16
|
Abstract
Our various efforts toward the synthesis of a set of novel sugar hybrid scaffolds of several biologically active natural products such as taxol, steroids, β-lactams, and otteliones are presented. We have shown the application of the hybrid approach to design and rapidly generate a library of novel natural product-like compounds, which may have interesting biological features, using metathesis and/or cycloaddition reactions as key steps.
Collapse
|
17
|
Trzoss L, Xu J, Lacoske MH, Mobley WC, Theodorakis EA. Illicium sesquiterpenes: divergent synthetic strategy and neurotrophic activity studies. Chemistry 2013; 19:6398-408. [PMID: 23526661 PMCID: PMC3875175 DOI: 10.1002/chem.201300198] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2013] [Indexed: 01/12/2023]
Abstract
Majucin-type sesquiterpenes from Illicium sp., such as jiadifenolide (2), jiadifenin (3), and (1R,10S)-2-oxo-3,4-dehydroxyneomajucin (4, ODNM), possess a complex caged chemical architecture and remarkable neurotrophic activities. As such, they represent attractive small-molecule leads against various neurodegenerative diseases. We present an efficient, enantioselective, and unified synthesis of 2, 3, and 4 and designed analogues that diverge from tetracyclic key intermediate 7. The synthesis of 7 is highlighted by the use of an enantioselective Robinson annulation reaction (construction of the AB rings), a Pd-mediated carbomethoxylation reaction (construction of the C ring), and a one-pot oxidative reaction cascade (construction of the D ring). Evaluation of the neurotrophic activity of these compounds led to the identification of several highly potent small molecules that significantly enhanced the activity of nerve growth factor (NGF) in PC-12 cells. Moreover, efforts to define the common pharmacophoric motif suggest that substitution at the C-10 center significantly affects bioactivity, while the hemiketal moiety of 2 and 3 and the C-1 substitution might not be critical to the neurotrophic activity.
Collapse
Affiliation(s)
- Lynnie Trzoss
- Department of Chemistry and Biochemistry, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0358, USA, Fax: (+)1-858-822-0386
| | - Jing Xu
- Department of Chemistry and Biochemistry, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0358, USA, Fax: (+)1-858-822-0386
| | - Michelle H. Lacoske
- Department of Chemistry and Biochemistry, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0358, USA, Fax: (+)1-858-822-0386
| | - William C. Mobley
- Department of Neurosciences, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0752, USA
| | - Emmanuel A. Theodorakis
- Department of Chemistry and Biochemistry, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0358, USA, Fax: (+)1-858-822-0386
| |
Collapse
|
18
|
Chatterjee B, Mondal D, Bera S. Asymmetric synthesis of a 12-membered macrolactone core and a 6-epi analogue of amphidinolide W from 4-pentenoic acid. ACTA ACUST UNITED AC 2012. [DOI: 10.1016/j.tetasy.2012.07.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
19
|
Yuan C, Chen M, Covey DF, Johnston LJ, Treistman SN. Cholesterol tuning of BK ethanol response is enantioselective, and is a function of accompanying lipids. PLoS One 2011; 6:e27572. [PMID: 22140451 PMCID: PMC3226590 DOI: 10.1371/journal.pone.0027572] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Accepted: 10/19/2011] [Indexed: 12/22/2022] Open
Abstract
In the search to uncover ethanol's molecular mechanisms, the calcium and voltage activated, large conductance potassium channel (BK) has emerged as an important molecule. We examine how cholesterol content in bilayers of 1,2-dioleoyl-3-phosphatidylethanolamine (DOPE)/sphingomyelin (SPM) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylethanolamine (POPE)/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylserine (POPS) affect the function and ethanol sensitivity of BK. In addition, we examine how manipulation of cholesterol in biological membranes modulates ethanol's actions on BK. We report that cholesterol levels regulate the change in BK channel open probability elicited by 50 mM ethanol. Low levels of cholesterol (<20%, molar ratio) supports ethanol activation, while high levels of cholesterol leads to ethanol inhibition of BK. To determine if cholesterol affects BK and its sensitivity to ethanol through a direct cholesterol-protein interaction or via an indirect action on the lipid bilayer, we used the synthetic enantiomer of cholesterol (ent-CHS). We found that 20% and 40% ent-CHS had little effect on the ethanol sensitivity of BK, when compared with the same concentration of nat-CHS. We accessed the effects of ent-CHS and nat-CHS on the molecular organization of DOPE/SPM monolayers at the air/water interface. The isotherm data showed that ent-CHS condensed DOPE/SPM monolayer equivalently to nat-CHS at a 20% concentration, but slightly less at a 40% concentration. Atomic force microscopy (AFM) images of DOPE/SPM membranes in the presence of ent-CHS or nat-CHS prepared with LB technique or vesicle deposition showed no significant difference in topographies, supporting the interpretation that the differences in actions of nat-CHS and ent-CHS on BK channel are not likely from a generalized action on bilayers. We conclude that membrane cholesterol influences ethanol's modulation of BK in a complex manner, including an interaction with the channel protein. Finally, our results suggest that an understanding of membrane protein function and modulation is impossible unless protein and surrounding lipid are considered as a functional unit.
Collapse
Affiliation(s)
- Chunbo Yuan
- Institute of Neurobiology, University of Puerto Rico, San Juan, Puerto Rico
| | - Maohui Chen
- Steacie Institute for Molecular Sciences, National Research Council of Canada, Ottawa, Ontario, Canada
| | - Douglas F. Covey
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Linda J. Johnston
- Steacie Institute for Molecular Sciences, National Research Council of Canada, Ottawa, Ontario, Canada
| | - Steven N. Treistman
- Institute of Neurobiology, University of Puerto Rico, San Juan, Puerto Rico
- * E-mail:
| |
Collapse
|
20
|
Kotora M, Hessler F, Eignerová B. Transition‐Metal‐Mediated or ‐Catalyzed Syntheses of Steroids and Steroid‐Like Compounds. European J Org Chem 2011. [DOI: 10.1002/ejoc.201100921] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Martin Kotora
- Dept. of Organic and Nuclear Chemistry, Faculty of Science, Charles University in Prague, Hlavova 8, 12843 Praha 2, Czech Republic, Fax: +420‐221‐951‐326
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovo nám. 2, 166 10 Praha 6, Czech Republic
| | - Filip Hessler
- Dept. of Organic and Nuclear Chemistry, Faculty of Science, Charles University in Prague, Hlavova 8, 12843 Praha 2, Czech Republic, Fax: +420‐221‐951‐326
| | - Barbara Eignerová
- Dept. of Organic and Nuclear Chemistry, Faculty of Science, Charles University in Prague, Hlavova 8, 12843 Praha 2, Czech Republic, Fax: +420‐221‐951‐326
| |
Collapse
|
21
|
Geoffroy P, Ressault B, Marchioni E, Miesch M. Norrish-Prins reaction as a key step in the synthesis of 14β-hydroxy-5α (or 5β or Δ(5,6))-pregnane derivatives. Steroids 2011; 76:1166-75. [PMID: 21645535 DOI: 10.1016/j.steroids.2011.05.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Revised: 05/09/2011] [Accepted: 05/13/2011] [Indexed: 11/30/2022]
Abstract
Numerous bioactive glycosteroids are characterized by aglycones bearing a 14β-hydroxy pregnane skeleton like boucerin and isoramanone. In general, the syntheses of the latter are achieved by acidic hydrolysis of the corresponding glycosteroids. These aglycones were also obtained by a combined Norrish type I-Prins reaction starting from the corresponding 12-keto-pregnane derivatives. However, for the Norrish-Prins reaction, no reports describe the influence of the A/B ring junction (cis or trans or Δ(5,6) double bond) or the influence of the substitution pattern at position 20. Herein, we describe the use of Norrish type I-Prins reactions to synthesize isoramanone and boucerin derivatives and their A/B cis and trans analogs. The influence of the parameters mentioned above is also presented. These studies showed that the A/B ring junction has little influence on the Norrish type I-Prins reaction but that the substitution pattern at position 20 is important. The presence of a dioxolane group induced not only the formation of the desired 14β-hydroxy pregnane derivatives in the highest yields but also the formation of new spiro derivatives.
Collapse
Affiliation(s)
- Philippe Geoffroy
- Université de Strasbourg, Institut de Chimie, Université, UMR 7177, Laboratoire de Chimie Organique Synthétique, 1 rue Blaise Pascal, BP 296/R8, 67008 Strasbourg-Cedex, France
| | | | | | | |
Collapse
|
22
|
Geoffroy P, Ressault B, Marchioni E, Miesch M. Synthesis of Hoodigogenin A, aglycone of natural appetite suppressant glycosteroids extracted from Hoodia gordonii. Steroids 2011; 76:702-8. [PMID: 21473873 DOI: 10.1016/j.steroids.2011.03.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 03/24/2011] [Accepted: 03/25/2011] [Indexed: 11/17/2022]
Abstract
14β-hydroxy pregnane glycosides extracted from Hoodia gordonii, a succulent plant isolated from Apocynaceae are suggested to have appetite suppressant properties in animals and humans. However, limited reports on biological studies concerning the appetite suppressant properties are available in the open literature. One reason for that is the poor availability of these glycosteroids because H. gordonii is a protected plant and the yield of extraction lies between 0.003% and 0.02%. Starting from 3α,12α-diacetoxy-pregnanone 1, we disclose in this report the synthesis of Hoodigogenin A, the aglycone of the natural 14β-hydroxy pregnane glycosides extracted from H. Gordonii.
Collapse
Affiliation(s)
- Philippe Geoffroy
- Université de Strasbourg-Institut de Chimie, UMR 7177-Laboratoire de Chimie Organique Synthétique-1, rue Blaise Pascal, BP 296/R8, 67008 Strasbourg-Cedex, France
| | | | | | | |
Collapse
|
23
|
D'Avanzo N, Hyrc K, Enkvetchakul D, Covey DF, Nichols CG. Enantioselective protein-sterol interactions mediate regulation of both prokaryotic and eukaryotic inward rectifier K+ channels by cholesterol. PLoS One 2011; 6:e19393. [PMID: 21559361 PMCID: PMC3084843 DOI: 10.1371/journal.pone.0019393] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Accepted: 03/29/2011] [Indexed: 02/06/2023] Open
Abstract
Cholesterol is the major sterol component of all mammalian cell plasma membranes and plays a critical role in cell function and growth. Previous studies have shown that cholesterol inhibits inward rectifier K+ (Kir) channels, but have not distinguished whether this is due directly to protein-sterol interactions or indirectly to changes in the physical properties of the lipid bilayer. Using purified bacterial and eukaryotic Kir channels reconstituted into liposomes of controlled lipid composition, we demonstrate by 86Rb+ influx assays that bacterial Kir channels (KirBac1.1 and KirBac3.1) and human Kir2.1 are all inhibited by cholesterol, most likely by locking the channels into prolonged closed states, whereas the enantiomer, ent-cholesterol, does not inhibit these channels. These data indicate that cholesterol regulates Kir channels through direct protein-sterol interactions likely taking advantage of an evolutionarily conserved binding pocket.
Collapse
Affiliation(s)
- Nazzareno D'Avanzo
- Department of Cell Biology and Physiology, and Center for Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Krzysztof Hyrc
- Department of Cell Biology and Physiology, and Center for Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Decha Enkvetchakul
- Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, St. Louis, Missouri, United States of America
| | - Douglas F. Covey
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Colin G. Nichols
- Department of Cell Biology and Physiology, and Center for Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, Missouri, United States of America
- * E-mail:
| |
Collapse
|
24
|
|
25
|
García Ruano JL, Alonso M, Cruz D, Fraile A, Martín MR, Peromingo MT, Tito A, Yuste F. Synthesis of bicyclo[3.1.0]hexanones via 1,3-dipolar cycloaddition of diazoalkanes to homochiral α-sulfinyl-2-cyclopentenones. Tetrahedron 2008. [DOI: 10.1016/j.tet.2008.08.088] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
26
|
Abstract
ent-Cholesterol was synthesized in 16 steps from commercially available (S)-citronellol. The overall yield for the synthesis was 2.0%. This route is amenable to gram-scale preparation of ent-cholesterol. Isotopic incorporation near the end of the synthesis was achieved using labeled methyl iodide. This synthesis is the most practical to date and will make ent-cholesterol more readily available to use as a probe of the function and metabolism of cholesterol.
Collapse
Affiliation(s)
- Jitendra D. Belani
- Department of Chemistry, 1102 Natural Sciences II, University of California, Irvine, Irvine, California 92697
| | - Scott D. Rychnovsky
- Department of Chemistry, 1102 Natural Sciences II, University of California, Irvine, Irvine, California 92697
| |
Collapse
|
27
|
|
28
|
Chapelon AS, Moraléda D, Rodriguez R, Ollivier C, Santelli M. Enantioselective synthesis of steroids. Tetrahedron 2007. [DOI: 10.1016/j.tet.2007.08.087] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
29
|
Blizzard TA, Gude C, Chan W, Birzin ET, Mojena M, Tudela C, Chen F, Knecht K, Su Q, Kraker B, Holmes MA, Rohrer SP, Hammond ML. Bridged androstenediol analogs as ER-β selective SERMs. Bioorg Med Chem Lett 2007; 17:2944-8. [PMID: 17448656 DOI: 10.1016/j.bmcl.2006.12.053] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2006] [Revised: 12/08/2006] [Accepted: 12/11/2006] [Indexed: 11/28/2022]
Abstract
A series of bridged androstenediol derivatives was prepared. The bridged compounds exhibited reduced ER-beta selectivity relative to uncyclized analogs.
Collapse
|
30
|
Mohapatra DK, Mondal D, Gurjar MK. Towards the enantioselective synthesis of anti-HIV agents litseaverticillols C and K from d-glucose. Tetrahedron 2007. [DOI: 10.1016/j.tet.2007.01.037] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
31
|
Ohkubo M, Uchikawa W, Matsushita H, Nakano A, Shirato T, Okamoto S. Stereoselective construction of 3a-methylhydrindanes starting from 2,7-enynol derivatives based on Ti(II)-mediated cyclization and Ru-catalyzed ring-closing metathesis. Tetrahedron Lett 2006. [DOI: 10.1016/j.tetlet.2006.05.030] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
32
|
Pogrebnoi S, Sarabèr FC, Jansen BJ, de Groot A. Synthesis of a chiral steroid ring D precursor starting from carvone. Tetrahedron 2006. [DOI: 10.1016/j.tet.2005.11.057] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
33
|
Rowicki T, Synoradzki L, Włostowski M. Calcium Pantothenate. Part 1. (R,S)-Pantolactone Technology Improvement at the Tonnage Scale. Ind Eng Chem Res 2006. [DOI: 10.1021/ie050774u] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tomasz Rowicki
- Laboratory of Technological Processes, Faculty of Chemistry, Warsaw University of Technology, ul. Noakowskiego 3, 00-664 Warszawa, Poland
| | - Ludwik Synoradzki
- Laboratory of Technological Processes, Faculty of Chemistry, Warsaw University of Technology, ul. Noakowskiego 3, 00-664 Warszawa, Poland
| | - Marek Włostowski
- Laboratory of Technological Processes, Faculty of Chemistry, Warsaw University of Technology, ul. Noakowskiego 3, 00-664 Warszawa, Poland
| |
Collapse
|
34
|
Hiroya K, Takahashi T, Shimomae K, Sakamoto T. The New Method for Introduction of an Allyl Group into the Angular Position of 2-(TBS-oxymethyl)-2,3,4,6,7,8-hexahydro-1-benzopyran-5-one and Its Application to Chiral Wieland-Miescher Type Compound Synthesis. Chem Pharm Bull (Tokyo) 2005; 53:207-13. [PMID: 15684520 DOI: 10.1248/cpb.53.207] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The stereoselective introduction of an allyl group into the angular position of 2-(TBS-oxymethyl)-2,3,4,6,7,8-hexahydro-1-benzopyran-5-one was accomplished using Birch reduction and an enolate trapping reaction. It was determined that the allyl group was introduced via an unexpected conformation-flipped from the initially formed one. Two diastereomeric Wieland-Miescher type compounds, having the allyl group at the angular position, were synthesized as optically pure forms.
Collapse
Affiliation(s)
- Kou Hiroya
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan.
| | | | | | | |
Collapse
|
35
|
Kaliappan KP, Ravikumar V. Design and synthesis of novel sugar-oxasteroid-quinone hybrids. Org Biomol Chem 2005; 3:848-51. [PMID: 15731871 DOI: 10.1039/b418659a] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new class of sugar-oxasteroid-quinone hybrid molecules has been designed and synthesized involving an efficient enyne metathesis/Diels-Alder reaction strategy.
Collapse
Affiliation(s)
- Krishna P Kaliappan
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, 400 076, India.
| | | |
Collapse
|
36
|
Abstract
Cholesterol plays a variety of significant roles in biological systems. However, the mechanisms by which cholesterol functions remain largely unclear. The enantiomer of cholesterol (ent-cholesterol)--which has identical physical properties, but opposite three-dimensional configuration compared to cholesterol--is a unique tool that can be used to better understand the mechanisms of cholesterol function. We review the literature pertaining to ent-cholesterol, focusing in particular on its use in biological studies.
Collapse
Affiliation(s)
- E J Westover
- Department of Molecular Biology and Pharmacology, Washington University School of Medicine, 660 S. Euclid, St. Louis, MO 63110, USA
| | | |
Collapse
|
37
|
Richter RK, Mickus DE, Rychnovsky SD, Molinski TF. Differential modulation of the antifungal activity of amphotericin B by natural and ent-cholesterol. Bioorg Med Chem Lett 2004; 14:115-8. [PMID: 14684310 DOI: 10.1016/j.bmcl.2003.10.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The addition of exogenous ent-cholesterol suppressed the antifungal activity of the amphotericin B when added to cultures of Candida albicans, but to a lesser extent than natural cholesterol. There were no detectable differences between added 2a or 2b on the antifungal activities of jaspamide or bengazole A, two unrelated antifungal natural products.
Collapse
Affiliation(s)
- Rowena K Richter
- Department of Chemistry, University of California, Davis, CA 95616, USA
| | | | | | | |
Collapse
|
38
|
Trudeau S, Deslongchamps P. Novel Synthesis of Highly Functionalized 14-β-Hydroxysteroids Related to Batrachotoxin and Ouabain. J Org Chem 2004; 69:832-8. [PMID: 14750812 DOI: 10.1021/jo0355606] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The use of anionic polycyclization was investigated in an effort to develop a versatile and convergent synthesis of advanced tetracyclic intermediates of batrachotoxin and ouabain analogues. Two new 5-(trialkylsilyl)-2-cyclohexenones as A ring precursors and a new Nazarov intermediate (D ring precursor) were prepared for this purpose. The reaction of the unsaturated beta-keto aldehyde A ring precursor with the enolate of the Nazarov intermediate afforded, after subsequent transformations, a 14-beta-hydroxysteroid with complete control of stereochemistry.
Collapse
Affiliation(s)
- Stéphane Trudeau
- Laboratoire de synthèse organique, Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
| | | |
Collapse
|
39
|
Abstract
We published recently our results on a new and convergent synthesis of natural steroids. The strategy was based on a cycloaddition reaction of Nazarov reagents 2 and 5 with cyclohexenones 1 and 4. In this paper we report results that deal with the synthesis of two new bicyclic Nazarov reagents (13 and 19) and their cycloaddition with two cyclohexenones (1 and 4). These new results constitute an important improvement concerning the versatility of the strategy since tetracycles having the stereochemistry found in natural steroids are now available.
Collapse
Affiliation(s)
- Olivier Lepage
- Laboratoire de synthèse organique, Institut de pharmacologie de Sherbrooke, Université de Sherbrooke, Québec, Canada
| | | |
Collapse
|
40
|
Mannock DA, McIntosh TJ, Jiang X, Covey DF, McElhaney RN. Effects of natural and enantiomeric cholesterol on the thermotropic phase behavior and structure of egg sphingomyelin bilayer membranes. Biophys J 2003; 84:1038-46. [PMID: 12547785 PMCID: PMC1302681 DOI: 10.1016/s0006-3495(03)74920-0] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Phospholipids, sphingolipids, and sterols are the major lipid components of the plasma membranes of eukaryotic cells. Because these three lipid classes occur naturally as enantiomerically pure compounds, enantiospecific lipid-lipid and lipid-sterol interactions could in principle occur in the lipid bilayers of eukaryotic plasma membranes. Although previous biophysical studies of phospholipid and phospholipid-sterol model membrane systems have consistently failed to observe such enantiomerically selective interactions, a recent monolayer study of the interactions of natural and enantiomeric cholesterol with egg sphingomyelin has apparently revealed the existence of enantiospecific sterol-sphingolipid interactions. To determine whether enantiospecific sterol-sphingolipid interactions also occur in more biologically relevant lipid-bilayer systems, differential scanning calorimetric, x-ray diffraction, and neutral buoyant-density measurements were utilized to study the effects of natural and enantiomeric cholesterol on the thermotropic phase behavior and structure of egg sphingomyelin bilayers. The calorimetry experiments show that the natural and enantiomeric cholesterol have essentially identical effects on the temperature, enthalpy, and cooperativity of the gel/liquid-crystalline phase transition of egg sphingomyelin bilayers within the limits of experimental error. As well, the x-ray diffraction and neutral buoyancy experiments indicate that bilayers formed from mixtures of natural or enantiomeric cholesterol and egg sphingomyelin have, within experimental uncertainty, the same structure and mass density. We thus conclude that significant enantioselective cholesterol-sphingolipid interactions do not occur in this lipid-bilayer model membrane system.
Collapse
Affiliation(s)
- David A Mannock
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, T6G 2H7 Canada
| | | | | | | | | |
Collapse
|