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HIRAMA M. Total synthesis and related studies of large, strained, and bioactive natural products. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2016; 92:290-329. [PMID: 27725470 PMCID: PMC5243947 DOI: 10.2183/pjab.92.290] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 08/10/2016] [Indexed: 06/06/2023]
Abstract
Our chemical syntheses and related scientific investigations of natural products with complex architectures and powerful biological activities are described, focusing on the very large 3 nm-long polycyclic ethers called the ciguatoxins, highly strained and labile chromoprotein antitumor antibiotics featuring nine-membered enediyne cores, and extremely potent anthelmintic macrolides called the avermectins.
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Affiliation(s)
- Masahiro HIRAMA
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Miyagi, Japan
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Akiba H, Tsumoto K. Thermodynamics of antibody–antigen interaction revealed by mutation analysis of antibody variable regions. ACTA ACUST UNITED AC 2015; 158:1-13. [DOI: 10.1093/jb/mvv049] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 03/11/2015] [Indexed: 01/20/2023]
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Nishio M, Umezawa Y, Fantini J, Weiss MS, Chakrabarti P. CH-π hydrogen bonds in biological macromolecules. Phys Chem Chem Phys 2015; 16:12648-83. [PMID: 24836323 DOI: 10.1039/c4cp00099d] [Citation(s) in RCA: 335] [Impact Index Per Article: 37.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
This is a sequel to the previous Perspective "The CH-π hydrogen bond in chemistry. Conformation, supramolecules, optical resolution and interactions involving carbohydrates", which featured in a PCCP themed issue on "Weak Hydrogen Bonds - Strong Effects?": Phys. Chem. Chem. Phys., 2011, 13, 13873-13900. Evidence that weak hydrogen bonds play an enormously important role in chemistry and biochemistry has now accumulated to an extent that the rigid classical concept of hydrogen bonds formulated by Pauling needs to be seriously revised and extended. The concept of a more generalized hydrogen bond definition is indispensable for understanding the folding mechanisms of proteins. The CH-π hydrogen bond, a weak molecular force occurring between a soft acid CH and a soft base π-electron system, among all is one of the most important and plays a functional role in defining the conformation and stability of 3D structures as well as in many molecular recognition events. This concept is also valuable in structure-based drug design efforts. Despite their frequent occurrence in organic molecules and bio-molecules, the importance of CH-π hydrogen bonds is still largely unknown to many chemists and biochemists. Here we present a review that deals with the evidence, nature, characteristics and consequences of the CH-π hydrogen bond in biological macromolecules (proteins, nucleic acids, lipids and polysaccharides). It is hoped that the present Perspective will show the importance of CH-π hydrogen bonds and stimulate interest in the interactions of biological macromolecules, one of the most fascinating fields in bioorganic chemistry. Implication of this concept is enormous and valuable in the scientific community.
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Affiliation(s)
- Motohiro Nishio
- The CHPI Institute, 705-6-338, Minamioya, Machida-shi, Tokyo 194-0031, Japan.
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Kavanagh O, Elliott CT, Campbell K. Progress in the development of immunoanalytical methods incorporating recombinant antibodies to small molecular weight biotoxins. Anal Bioanal Chem 2015; 407:2749-70. [PMID: 25716465 DOI: 10.1007/s00216-015-8502-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2014] [Revised: 01/15/2015] [Accepted: 01/19/2015] [Indexed: 01/08/2023]
Abstract
Rapid immunoanalytical screening of food and environmental samples for small molecular weight (hapten) biotoxin contaminations requires the production of antibody reagents that possess the requisite sensitivity and specificity. To date animal-derived polyclonal (pAb) and monoclonal (mAb) antibodies have provided the binding element of the majority of these assays but recombinant antibodies (rAb) isolated from in vitro combinatorial phage display libraries are an exciting alternative due to (1) circumventing the need for experimental animals, (2) speed of production in commonly used in vitro expression systems and (3) subsequent molecular enhancement of binder performance. Short chain variable fragments (scFv) have been the most commonly employed rAb reagents for hapten biotoxin detection over the last two decades but antibody binding fragments (Fab) and single domain antibodies (sdAb) are increasing in popularity due to increased expression efficiency of functional binders and superior resistance to solvents. rAb-based immunochromatographic assays and surface plasmon resonance (SPR) biosensors have been reported to detect sub-regulatory levels of fungal (mycotoxins), marine (phycotoxins) and aquatic biotoxins in a wide range of food and environmental matrices, however this technology has yet to surpass the performances of the equivalent mAb- and pAb-based formats. As such the full potential of rAb technology in hapten biotoxin detection has yet to be achieved, but in time the inherent advantages of engineered rAb are set to provide the next generation of ultra-high performing binder reagents for the rapid and specific detection of hapten biotoxins.
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Affiliation(s)
- Owen Kavanagh
- Institute for Global Food Security (IGFS), School of Biological Sciences, Queen's University Belfast, Belfast, Northern Ireland, UK,
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Sasao A, Suwa Y, Aso T, Kohmatsu H, Ohtsu Y, Mishima S, Yonemitsu K, Morioka H, Nishitani Y. Single-chain variable fragment technology in forensic toxicological analysis: production of an antibody to fluvoxamine. Forensic Toxicol 2012. [DOI: 10.1007/s11419-012-0163-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Small molecule immunosensing using surface plasmon resonance. SENSORS 2010; 10:7323-46. [PMID: 22163605 PMCID: PMC3231171 DOI: 10.3390/s100807323] [Citation(s) in RCA: 118] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Revised: 07/15/2010] [Accepted: 07/25/2010] [Indexed: 11/17/2022]
Abstract
Surface plasmon resonance (SPR) biosensors utilize refractive index changes to sensitively detect mass changes at noble metal sensor surface interfaces. As such, they have been extensively applied to immunoassays of large molecules, where their high mass and use of sandwich immunoassay formats can result in excellent sensitivity. Small molecule immunosensing using SPR is more challenging. It requires antibodies or high-mass or noble metal labels to provide the required signal for ultrasensitive assays. Also, it can suffer from steric hindrance between the small antigen and large antibodies. However, new studies are increasingly meeting these and other challenges to offer highly sensitive small molecule immunosensor technologies through careful consideration of sensor interface design and signal enhancement. This review examines the application of SPR transduction technologies to small molecule immunoassays directed to different classes of small molecule antigens, including the steroid hormones, toxins, drugs and explosives residues. Also considered are the matrix effects resulting from measurement in chemically complex samples, the construction of stable sensor surfaces and the development of multiplexed assays capable of detecting several compounds at once. Assay design approaches are discussed and related to the sensitivities obtained.
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Caillaud A, de la Iglesia P, Darius HT, Pauillac S, Aligizaki K, Fraga S, Chinain M, Diogène J. Update on methodologies available for ciguatoxin determination: perspectives to confront the onset of ciguatera fish poisoning in Europe. Mar Drugs 2010; 8:1838-907. [PMID: 20631873 PMCID: PMC2901828 DOI: 10.3390/md8061838] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2010] [Revised: 05/18/2010] [Accepted: 06/10/2010] [Indexed: 11/29/2022] Open
Abstract
Ciguatera fish poisoning (CFP) occurs mainly when humans ingest finfish contaminated with ciguatoxins (CTXs). The complexity and variability of such toxins have made it difficult to develop reliable methods to routinely monitor CFP with specificity and sensitivity. This review aims to describe the methodologies available for CTX detection, including those based on the toxicological, biochemical, chemical, and pharmaceutical properties of CTXs. Selecting any of these methodological approaches for routine monitoring of ciguatera may be dependent upon the applicability of the method. However, identifying a reference validation method for CTXs is a critical and urgent issue, and is dependent upon the availability of certified CTX standards and the coordinated action of laboratories. Reports of CFP cases in European hospitals have been described in several countries, and are mostly due to travel to CFP endemic areas. Additionally, the recent detection of the CTX-producing tropical genus Gambierdiscus in the eastern Atlantic Ocean of the northern hemisphere and in the Mediterranean Sea, as well as the confirmation of CFP in the Canary Islands and possibly in Madeira, constitute other reasons to study the onset of CFP in Europe [1]. The question of the possible contribution of climate change to the distribution of toxin-producing microalgae and ciguateric fish is raised. The impact of ciguatera onset on European Union (EU) policies will be discussed with respect to EU regulations on marine toxins in seafood. Critical analysis and availability of methodologies for CTX determination is required for a rapid response to suspected CFP cases and to conduct sound CFP risk analysis.
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Affiliation(s)
- Amandine Caillaud
- IRTA, Ctra. Poble Nou, Km 5,5. 43540 Sant Carles de la Ràpita, Spain; E-Mails: (A.C.); (P.I.)
| | - Pablo de la Iglesia
- IRTA, Ctra. Poble Nou, Km 5,5. 43540 Sant Carles de la Ràpita, Spain; E-Mails: (A.C.); (P.I.)
| | - H. Taiana Darius
- Laboratoire des micro-algues toxiques, Institut Louis Malardé, BP30, 98713 Papeete Tahiti, French Polynesia; E-Mails: (H.T.D.); (M.C.)
| | - Serge Pauillac
- Institut Pasteur, 25-28 rue du docteur Roux, 75 015 Paris, France; E-Mail: (S.P.)
| | - Katerina Aligizaki
- Department of Botany, School of Biology, Faculty of Sciences, Aristotle University, 54 124 Thessaloniki, Greece; E-Mail: (K.A.)
| | - Santiago Fraga
- Instituto Español de Oceanografía, Subida a Radio Faro, 50, 36390 Vigo, Spain; E-Mail: (S.F.)
| | - Mireille Chinain
- Laboratoire des micro-algues toxiques, Institut Louis Malardé, BP30, 98713 Papeete Tahiti, French Polynesia; E-Mails: (H.T.D.); (M.C.)
| | - Jorge Diogène
- IRTA, Ctra. Poble Nou, Km 5,5. 43540 Sant Carles de la Ràpita, Spain; E-Mails: (A.C.); (P.I.)
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Rich RL, Myszka DG. Grading the commercial optical biosensor literature-Class of 2008: 'The Mighty Binders'. J Mol Recognit 2010; 23:1-64. [PMID: 20017116 DOI: 10.1002/jmr.1004] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Optical biosensor technology continues to be the method of choice for label-free, real-time interaction analysis. But when it comes to improving the quality of the biosensor literature, education should be fundamental. Of the 1413 articles published in 2008, less than 30% would pass the requirements for high-school chemistry. To teach by example, we spotlight 10 papers that illustrate how to implement the technology properly. Then we grade every paper published in 2008 on a scale from A to F and outline what features make a biosensor article fabulous, middling or abysmal. To help improve the quality of published data, we focus on a few experimental, analysis and presentation mistakes that are alarmingly common. With the literature as a guide, we want to ensure that no user is left behind.
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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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Smirnova I, Kasho V, Sugihara J, Kaback HR. Probing of the rates of alternating access in LacY with Trp fluorescence. Proc Natl Acad Sci U S A 2009; 106:21561-6. [PMID: 19959662 PMCID: PMC2799877 DOI: 10.1073/pnas.0911434106] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2009] [Indexed: 11/18/2022] Open
Abstract
Sugar/H(+) symport by lactose permease (LacY) utilizes an alternating access mechanism in which sugar and H(+) binding sites in the middle of the molecule are alternatively exposed to either side of the membrane by sequential opening and closing of inward- and outward-facing hydrophilic cavities. Here, we introduce Trp residues on either side of LacY where they are predicted to be in close proximity to side chains of natural Trp quenchers in either the inward- or outward-facing conformers. In the inward-facing conformer, LacY is tightly packed on the periplasmic side, and Trp residues placed at positions 245 (helix VII) or 378 (helix XII) are in close contact with His-35 (helix I) or Lys-42 (helix II), respectively. Sugar binding leads to unquenching of Trp fluorescence in both mutants, a finding clearly consistent with opening of the periplasmic cavity. The pH dependence of Trp-245 unquenching exhibits a pK(a) of 8, typical for a His side chain interacting with an aromatic group. As estimated from stopped-flow studies, the rate of sugar-induced opening is approximately 100 s(-1). On the cytoplasmic side, Phe-140 (helix V) and Phe-334 (helix X) are located on opposite sides of a wide-open hydrophilic cavity. In precisely the opposite fashion from the periplasmic side, mutant Phe-140-->Trp/Phe-334-->His exhibits sugar-induced Trp quenching. Again, quenching is pH dependent (pK(a) = 8), but remarkably, the rate of sugar-induced quenching is only approximately 0.4 s(-1). The results provide yet another strong, independent line of evidence for the alternating access mechanism and demonstrate that the methodology described provides a sensitive probe to measure rates of conformational change in membrane transport proteins.
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Affiliation(s)
- Irina Smirnova
- Department of Physiology, University of California, Los Angeles, CA 90095-7327, USA
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TSUMOTO K, UI M. Rational Fragment-design Method Based on a Thermodynamic Analysis. YAKUGAKU ZASSHI 2009; 129:1311-7. [DOI: 10.1248/yakushi.129.1311] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Kouhei TSUMOTO
- Graduate School of Frontier Sciences, The University of Tokyo
| | - Mihoko UI
- Graduate School of Frontier Sciences, The University of Tokyo
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Llewellyn LE. Sodium channel inhibiting marine toxins. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2009; 46:67-97. [PMID: 19184585 DOI: 10.1007/978-3-540-87895-7_3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Saxitoxin (STX), tetrodotoxin (TTX) and their many chemical relatives are part of our daily lives. From killing people who eat seafood containing these toxins, to being valuable research tools unveiling the invisible structures of their pharmacological receptor, their global impact is beyond measure. The pharmacological receptor for these toxins is the voltage-gated sodium channel which transports Na ions between the exterior to the interior of cells. The two structurally divergent families of STX and TTX analogues bind at the same location on these Na channels to stop the flow of ions. This can affect nerves, muscles and biological senses of most animals. It is through these and other toxins that we have developed much of our fundamental understanding of the Na channel and its part in generating action potentials in excitable cells.
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Affiliation(s)
- Lyndon E Llewellyn
- Australian Institute of Marine Science, Townsville MC, QLD 4810, Australia.
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Interaction of ladder-shaped polyethers with transmembrane alpha-helix of glycophorin A as evidenced by saturation transfer difference NMR and surface plasmon resonance. Bioorg Med Chem Lett 2008; 18:6115-8. [PMID: 18947999 DOI: 10.1016/j.bmcl.2008.10.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2008] [Revised: 09/27/2008] [Accepted: 10/04/2008] [Indexed: 11/22/2022]
Abstract
Ladder-shaped polyether (LSP) compounds are thought to interact with transmembrane alpha-helices, but direct evidence has scarcely obtained for these interactions. We adopted a transmembrane alpha-helix of glycophorin A, and quantitatively evaluated its interaction with LSPs such as yessotoxin (YTX), desulfated YTX and artificial LSPs, using surface plasmon resonance and saturation transfer difference NMR. As a result, dissociation constants (K(D)) of YTX and desulfated YTX to a transmembrane domain peptide of glycophorin A were determined to be in the submillimolar range. Furthermore, in saturation transfer difference NMR, the signals at the polyene side chain and the angular methyl groups of YTX were significantly attenuated, which probably comprised an interacting interface of LSPs with a transmembrane alpha-helix. These results suggest that hydrophobic interaction plays an important role in molecular recognition of the alpha-helix peptide by LSPs.
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