Name: regioselective o-glycosylation of nucleosides via the temporary 2',3'-diol protection by a boronic ester for the synthesis of disaccharide nucleosides
Uploaded: 2018-07-26T13:00:00.000+00:00
Duration: 8 min 46 s
Description: Watch this Scientific Journal Video about Regioselective O-Glycosylation of Nucleosides via the Temporary 2',3'-Diol Protection by a Boronic Ester for the Synthesis of Disaccharide Nucleosides at JoVE

Diese Forschung wurde finanziert durch Grants-in-aid vom Ministerium für Bildung, Kultur, Sport, Wissenschaft und Technologie (MEXT) von Japan (Nr. 15K 00408, 24659011, 24640156, 245900425 und 22390005 für Shin Aoki), durch einen Zuschuss aus der Tokyo biochemische Forschung Stiftung, Tokyo, Japan, und durch den TUS (Tokyo University of Science) Fonds für strategische Forschungsschwerpunkte. Wir möchte Noriko Sawabe (Fakultät für pharmazeutische Wissenschaften, Tokyo University of Science) für die Messung von NMR-Spektren, Fukiko Hasegawa (Fakultät für pharmazeutische Wissenschaften, Tokyo University of Science) für die Messung der Masse Spektren und Tomoko Matsuo (Research Institute for Science and Technology, Tokyo University of Science) für die Messungen der elementaren Analysen.

Die Autoren haben nichts preisgeben.

Dieses Manuskript soll eine bequeme synthetische Methode vorzubereitende Disaccharid Nukleoside mit ungeschützten Ribonucleosides ohne mühsame schützende Gruppe Manipulationen zeigen. Hier berichten wir über die Regioselective O- glykosylierungen Nukleoside über die temporäre 2', 3'-Diol Schutz durch eine zyklische boronic Ester (Abbildung 1B)51.
Die Vorbereitung der zyklischen boronic Ester Zwischen...

Disaccharid Nukleoside, die Konjugate von einem Nukleosid und ein Kohlenhydrat Glyko-sind verbunden über eine O-glykosidisch bond, bilden eine wertvolle Klasse von natürlich vorkommenden Kohlenhydrate Derivate1,2 ,3,4,5,6,7. Zum Beispiel, fließen sie in biologischer Makromoleküle wie tRNA (Transfer-Ribonukleinsäure) und poly(ADP-ribose) (ADP = Adenosin Diphosphat), sowie in einigen Antibiotika und anderen biologisch aktiven Substanzen (z. B. Adenophostins, Amicetins, Ezomycin)5,6,8,9,10,11,12,13, 14,15,16,17,18,19. Daher sollen Disaccharid Nukleosiden und deren Derivate Bleiverbindungen für Droge-Entdeckung-Forschung sein. Die Methoden für die Synthese von Disaccharid Nukleoside sind in drei Kategorien eingeteilt; enzymatische O- Glykosylierung20,21, chemische N- Glykosylierung5,9,16,22,23, 24, und chemische O- Glykosylierung7,9,14,16,18,19,24, 25,26,27,28,29,30,31,32,33, 34,35,36,37. Insbesondere wäre chemische O- Glykosylierung eine effiziente Methode für die Stereoselective Synthese und große Synthese von Disaccharid Nukleoside. Bisherige Untersuchungen haben gezeigt, dass die O- Glykosylierung von 2'-Deoxyribonucleoside 2 mit dem Thioglycosyl Geber 1, mit der Kombination von p- Toluenesulfenyl-Chlorid und Silber triflate, bietet die gewünscht von Disaccharid Nukleosid 3 (Abbildung 1A; AR = Aryl und PG = Schutzgruppe)38.
Nach diesen Ergebnissen beschlossen wir, O- Glykosylierung von Ribonucleosides Anwendung des p- Toluenesulfenyl-Chlorid/Silber triflate Promotor-Systems zu entwickeln. Während mehrere Beispiele für die O- Glykosylierung von teilweise geschützten Ribonucleosides nachgewiesen7,9,14,16,18,wurden19 ,24,32,33,34,35,36,37, die Verwendung von ungeschützten oder zeitlich begrenzt geschützt Ribonucleosides als ein a1-Akzeptor für O- Glykosylierung geringfügig berichtet worden. Daher würde die Entwicklung Regioselective O- Glykosylierung von ungeschützten oder zeitlich begrenzt geschützt Ribonucleosides eine nützlicher synthetische Methode bieten, ohne den Schutz Gruppe Manipulationen des Ribonucleosides. Für die Erreichung der Regioselective O- Glykosylierung von Ribonucleosides konzentrierten wir uns auf die Bor-Verbindungen, weil mehrere Beispiele für Regio - und/oder Stereoselective Acylation, Alkylierung, Silylation und Glykosylierung von Kohlenhydraten Derivate von boronic unterstützt oder Borinic Säure wurden berichtet,39,40,41,42,43,44,45 ,46,47,48,49,50. In diesem Artikel zeigen wir das Verfahren für die Synthese von Disaccharid Nukleoside Nutzung Regioselective O- Glykosylierung auf die 5'-Hydroxylgruppe des Ribonucleosides über einen zwischengeschalteten boronic Ester. In der hier vorgestellten Strategie würde boronic Ester intermediate 6 gewährt werden, durch die Veresterung von Ribonucleoside 4 mit dem boronic Säure 5, wodurch die Regioselective O- Glykosylierung auf die 5'-Hydroxylgruppe mit Thioglycosyl Geber 7 Disaccharid Nukleosid 8 (Abbildung 1B)51geben. Wir untersuchten auch die Interaktion zwischen einem Ribonucleoside und boronic Säure durch Kernspinresonanz (NMR) Spektroskopie, um die Bildung von boronic Ester zu beobachten. Veresterung zu einem boronic Ester und eine Glykosylierung Reaktion erfordern wasserfreie Bedingungen um die Hydrolyse von boronic Ester und der a1-Spender zu verhindern. In diesem Artikel zeigen wir die typischen Verfahren um die wasserfreien Bedingungen für erfolgreiche Glycosylation Reaktionen für Forscher und Studenten nicht nur in der Chemie, sondern auch in anderen Forschungsbereichen zu erhalten.

<table><tbody><tr><td>Silver trifluoromethanesulfonate</td><td>Nacalai Tesque</td><td>34945-61</td><td></td></tr><tr><td>Phenylboronic acid (contains varying amounts of anhydride)</td><td>Tokyo Chemical Industry</td><td>B0857</td><td></td></tr><tr><td>&lt;em&gt;p&lt;/em&gt;-Methoxyphenylboronic acid</td><td>Wako Pure Chemical Industries</td><td>321-69201</td><td></td></tr><tr><td>4-(Trifluoromethyl)phenylboronic acid (contains varying amounts of anhydride)</td><td>Tokyo Chemical Industry</td><td>T1788</td><td></td></tr><tr><td>2,4-Difluorophenylboronic acid (contains varying amounts of anhydride)</td><td>Tokyo Chemical Industry</td><td>D3391</td><td></td></tr><tr><td>Cyclopentylboronic acid (contains varying amounts of Anhydride)</td><td>Tokyo Chemical Industry</td><td>C2442</td><td></td></tr><tr><td>4-Nitrophenylboronic acid (contains varying amounts of anhydride)</td><td>Tokyo Chemical Industry</td><td>N0812</td><td></td></tr><tr><td>4-Hexylphenylboronic acid (contains varying amounts of anhydride)</td><td>Tokyo Chemical Industry</td><td>H1489</td><td></td></tr><tr><td>Adenosine</td><td>Merck KGaA</td><td>862.</td><td></td></tr><tr><td>Guanosine</td><td>Acros Organics</td><td>411130050</td><td></td></tr><tr><td>Cytidine</td><td>Tokyo Chemical Industry</td><td>C0522</td><td></td></tr><tr><td>Uridine</td><td>Tokyo Chemical Industry</td><td>U0020</td><td></td></tr><tr><td>5-Fluorouridine</td><td>Tokyo Chemical Industry</td><td>F0636</td><td></td></tr><tr><td>5-Methyluridine</td><td>Sigma</td><td>M-9885</td><td></td></tr><tr><td>Methylamine (40% in Methanol,&amp;nbsp;ca. 9.8mol/L)</td><td>Tokyo Chemical Industry</td><td>M1016</td><td></td></tr><tr><td>&lt;em&gt;N,N&lt;/em&gt;-dimethyl-4-aminopyridine</td><td>Wako Pure Chemical Industries</td><td>044-19211</td><td></td></tr><tr><td>Acetic anhydride</td><td>Nacalai Tesque</td><td>00226-15</td><td></td></tr><tr><td>Pyridine, Dehydrated</td><td>Wako Pure Chemical Industries</td><td>161-18453</td><td></td></tr><tr><td>Acetonitrile</td><td>Kanto Chemical</td><td>01031-96</td><td></td></tr><tr><td>1,4-Dioxane</td><td>Nacalai Tesque</td><td>13622-73</td><td></td></tr><tr><td>Dichloromethane</td><td>Wako Pure Chemical Industries</td><td>130-02457</td><td></td></tr><tr><td>Propionitrile</td><td>Wako Pure Chemical Industries</td><td>164-04756</td><td></td></tr><tr><td>Molecular sieves 4A powder</td><td>Nacalai Tesque</td><td>04168-65</td><td></td></tr><tr><td>Molecular sieves 3A powder</td><td>Nacalai Tesque</td><td>04176-55</td><td></td></tr><tr><td>Celite 545RVS</td><td>Nacalai Tesque</td><td>08034-85</td><td></td></tr><tr><td>Acetonitrile-D3 (D,99.8%)</td><td>Cambridge Isotope Laboratories</td><td>DLM-21-10</td><td></td></tr><tr><td>Trifluoroacetic acid</td><td>Nacalai Tesque</td><td>34831-25</td><td></td></tr><tr><td>TLC Silica gel 60 F&lt;sub&gt;254&lt;/sub&gt;</td><td>Merck KGaA</td><td>1.05715.0001</td><td></td></tr><tr><td>Chromatorex</td><td>Fuji Silysia Chemical</td><td>FL100D</td><td></td></tr><tr><td>Sodium hydrogen carbonate</td><td>Wako Pure Chemical Industries</td><td>191-01305</td><td></td></tr><tr><td>Hydrochloric acid</td><td>Wako Pure Chemical Industries</td><td>080-01061</td><td></td></tr><tr><td>Sodium sulfate</td><td>Nacalai Tesque</td><td>31915-96</td><td></td></tr><tr><td>Chloroform</td><td>Kanto Chemical</td><td>07278-81</td><td></td></tr><tr><td>Sodium chloride</td><td>Wako Pure Chemical Industries</td><td>194-01677</td><td></td></tr><tr><td>Methanol</td><td>Nacalai Tesque</td><td>21914-74</td><td></td></tr><tr><td>JEOL Always 300</td><td>JEOL</td><td></td><td>Measurement of NMR</td></tr><tr><td>Lamda 400</td><td>JEOL</td><td></td><td>Measurement of NMR</td></tr><tr><td>PerkinElmer Spectrum 100 FT-IR Spectrometer</td><td>Perkin Elmer</td><td></td><td>Measurement of IR</td></tr><tr><td>JEOL JMS-700</td><td>JEOL</td><td></td><td>Measurement of MS</td></tr><tr><td>PerkinElmer CHN 2400 analyzer</td><td>Perkin Elmer</td><td></td><td>Measurement of elemental analysis</td></tr><tr><td>JASCO P-1030 digital polarimeter</td><td>JASCO</td><td></td><td>Measurement of optical rotation</td></tr><tr><td>JASCO PU-2089 Plus intelligent HPLC pump</td><td>JASCO</td><td></td><td>For HPLC</td></tr><tr><td>Jasco UV-2075 Plus Intelligent UV/Vis Detector</td><td>JASCO</td><td></td><td>For HPLC</td></tr><tr><td>Rheodyne Model 7125 Injector</td><td>Sigma-Aldrich</td><td>58826</td><td>For HPLC</td></tr><tr><td>Chromatopac C-R8A</td><td>Shimadzu</td><td></td><td>For HPLC</td></tr><tr><td>Senshu Pak Pegasil ODS</td><td>Senshu Scientific</td><td></td><td>For HPLC</td></tr><tr><td>&lt;em&gt;p&lt;/em&gt;-Toluenesulfenyl&amp;nbsp;chloride</td><td></td><td></td><td>Prepared&amp;nbsp; Ref. 38</td></tr><tr><td>Phenyl 6-O-acetyl-2,3,4-tri-&lt;em&gt;O&lt;/em&gt;-benzyl-1-thio-a-D-mannopyranoside (a-&lt;strong&gt;9&lt;/strong&gt;)</td><td></td><td></td><td>Prepared&amp;nbsp; Ref. 52</td></tr><tr><td>4-Metylphenyl 2,3,4,6-tetra-&lt;em&gt;O&lt;/em&gt;-benzoyl-1-thio-b-D-galactopyranoside (b-&lt;strong&gt;21&lt;/strong&gt;)</td><td></td><td></td><td>Prepared&amp;nbsp; Ref. 53</td></tr><tr><td>4-Metylphenyl 2,3,4,6-tetra-&lt;em&gt;O&lt;/em&gt;-benzoyl-1-thio-b-D-glucopyranoside (b-&lt;strong&gt;31&lt;/strong&gt;)</td><td></td><td></td><td>Prepared&amp;nbsp; Ref. 57</td></tr><tr><td>4-Metylphenyl 2,3,4,6-tetra-&lt;em&gt;O&lt;/em&gt;-benzoyl-1-thio-a-D-Mannopyranoside (a-&lt;strong&gt;32&lt;/strong&gt;)</td><td></td><td></td><td>Prepared&amp;nbsp; Ref. 67</td></tr><tr><td>6-&lt;em&gt;N&lt;/em&gt;-Benzoyladenosine (&lt;strong&gt;14&lt;/strong&gt;)</td><td></td><td></td><td>Prepared&amp;nbsp; Ref. 54</td></tr><tr><td>2-&lt;em&gt;N&lt;/em&gt;-Isobutyrylguanosine (&lt;strong&gt;16&lt;/strong&gt;)</td><td></td><td></td><td>Prepared&amp;nbsp; Ref. 55</td></tr><tr><td>4-&lt;em&gt;N&lt;/em&gt;-Benzoylcytidine (&lt;strong&gt;20&lt;/strong&gt;)</td><td></td><td></td><td>Prepared&amp;nbsp; Ref. 56</td></tr></tbody></table>

regioselective o-glycosylation of nucleosides via the temporary 2',3'-diol protection by a boronic ester for the synthesis of disaccharide nucleosides

Disaccharid Nukleoside, die aus Disaccharid und Nucleobase Moieties bestehen, sind als wertvolle Gruppe von Naturprodukten mit vielfältigen Bioactivities bekannt. Obwohl chemische O- Glykosylierung eine allgemein positive Strategie Disaccharid Nukleoside zu synthetisieren ist, erfordert die Vorbereitung von Substraten wie a1 Geber und Akzeptoren mühsam schützende Gruppe Manipulationen und eine Reinigung bei jeder synthetische Schritt. In der Zwischenzeit mehrere Forschergruppen haben berichtet, dass boronic und Borinic Ester dienen als ein Schutz oder Aktivierung Gruppe von Kohlenhydrat-Derivate, die Regio - und/oder Stereoselective Acylation, Alkylierung, Silylation und Glykosylierung zu erreichen. In diesem Artikel zeigen wir das Verfahren für die Regioselective O- Glykosylierung von ungeschützten Ribonucleosides Nutzung boronic Säure. Die Veresterung von 2', 3'-Diol Ribonucleosides mit boronic Säure macht den vorübergehenden Schutz von Diol und folgenden O- Glykosylierung mit einem a1-Spender im Beisein von p- Toluenesulfenyl Chlorid und Silber triflate, Genehmigungen die Regioselective Reaktion der 5'-Hydroxyl-Gruppe das Disaccharid Nukleoside leisten. Diese Methode kann auf verschiedene Nukleoside, z. B. Guanosin Adenosin, Cytidin, Uridin, 5 Metyluridine und 5-Fluorouridine angewendet werden. Dieser Artikel und das dazugehörige Video darstellen (Bild-) Informationen für die O- Glykosylierung von ungeschützten Nukleosiden und ihre Entsprechungen für die Synthese von nicht nur Disaccharid Nukleoside, sondern auch eine Vielzahl von biologisch relevante Derivate.

Die Ergebnisse der O- Glykosylierung von Uridin 10 mit Thiomannoside α -9 sind in Tabelle 160,61zusammengefasst. Eintrag 1 führte die O- Glykosylierung von 10 mit α -9 bei fehlender boronic Säure Derivate bei der Bildung von einer komplizierten Mischung. Im Eintrag 2, 10 und Phenylboronic Säure 11a</...

Watch this Scientific Journal Video about Regioselective O-Glycosylation of Nucleosides via the Temporary 2',3'-Diol Protection by a Boronic Ester for the Synthesis of Disaccharide Nucleosides at JoVE

Regioselective O-Glycosylation of Nucleosides via the Temporary 2',3'-Diol Protection by a Boronic Ester for the Synthesis of Disaccharide Nucleosides

Hier präsentieren wir Protokolle für die Synthese von Disaccharid Nukleoside von Regioselective O- Glykosylierung der Ribonucleosides über einen vorübergehenden Schutz von ihren 2', 3'-Diol Moieties unter Verwendung einer zyklischen boronic Ester. Diese Methode gilt für mehrere ungeschützte Nukleoside wie Adenosin, Guanosin, Cytidin, Uridin, 5 Methyluridine und 5-Fluorouridine, entsprechende Disaccharid Nukleoside zu geben.

Regioselective O- Glykosylierung Nukleoside über die temporäre 2', 3'-Diol Schutz durch eine Boronic Ester für die Synthese von Disaccharid Nukleosiden

Disaccharide nucleosides, which consist of disaccharide and nucleobase moieties, have been known as a valuable group of natural products having ...

regioselective-o-glycosylation-nucleosides-via-temporary-2-3-diol

Research

JoVE Journal

Chemistry

Regioselective O-Glycosylation of Nucleosides via the Temporary 2',3'-Diol Protection by a Boronic Ester for the Synthesis of Disaccharide Nucleosides

8.6K Aufrufe.  Tokyo University of Science. Hier präsentieren wir Protokolle für die Synthese von Disaccharid Nukleoside von Regioselective O- Glykosylierung der Ribonucleosides über einen vorübergehenden Schutz von ihren 2', 3'-Diol Moieties unter Verwendung einer zyklischen boronic Ester. Diese Methode gilt für mehrere ungeschützte Nukleoside wie Adenosin, Guanosin, Cytidin, Uridin, 5 Methyluridine und 5-Fluorouridine, entsprechende Disaccharid Nukleoside zu geben.

Serie: Regioselective O-Glycosylation of Nucleosides via the Temporary 2',3'-Diol Protection by a Boronic Ester for the Synthesis of Disaccharide Nucleosides

Nucleoside Triphosphates - From Synthesis to Biochemical Characterization

The traditional strategy for the introduction of chemical functionalities is the use of solid-phase synthesis by appending suitably modified phosphoramidite precursors to the nascent chain. However, the conditions used during the synthesis and the restriction to rather short sequences hamper the applicability of this methodology. On the other hand, modified nucleoside triphosphates are activated building blocks that have been employed for the mild introduction of numerous functional groups into nucleic acids, a strategy that paves the way for the use of modified nucleic acids in a wide-ranging palette of practical applications such as functional tagging and generation of ribozymes and DNAzymes. One of the major challenges resides in the intricacy of the methodology leading to the isolation and characterization of these nucleoside analogues.
	
	In this video article, we present a detailed protocol for the synthesis of these modified analogues using phosphorous(III)-based reagents. In addition, the procedure for their biochemical characterization is divulged, with a special emphasis on primer extension reactions and TdT tailing polymerization. This detailed protocol will be of use for the crafting of modified dNTPs and their further use in chemical biology.

The protocol described herein aims to explain and abridge the numerous obstacles in the way of the intricate route leading to modified nucleoside triphosphates. Consequently, this protocol facilitates both the synthesis of these activated building-blocks and their availability for practical applications.

Nucleosidtriphosphaten - von der Synthese zur biochemischen Charakterisierung

The  traditional strategy for the introduction of chemical functionalities is the  use of solid-phase synthesis by appending suitably modified ...

Forschung

Chemie

Synthesis of Indoxyl-glycosides for Detection of Glycosidase Activities

Indoxyl glycosides proved to be valuable and versatile tools for monitoring glycosidase activities. Indoxyls are released by enzymatic hydrolysis and are rapidly oxidized, for example by atmospheric oxygen, to indigo type dyes. This reaction enables fast and easy screening in vivo without isolation or purification of enzymes, as well as rapid tests on agar plates or in solution (e.g., blue-white screening, micro-wells) and is used in biochemistry, histochemistry, bacteriology and molecular biology. Unfortunately the synthesis of such substrates proved to be difficult, due to various side reactions and the low reactivity of the indoxyl hydroxyl function. Especially for glucose type structures low yields were observed. Our novel approach employs indoxylic acid ester as key intermediates. Indoxylic acid esters with varied substitution patterns were prepared on scalable pathways. Phase transfer glycosylations with those acceptors and peracetylated glycosyl halides can be performed under common conditions in high yields. Ester cleavage and subsequent mild silver mediated glycosylation yields the peracetylated indoxyl glycosides in high yields. Finally deprotection is performed according to Zempl&#233;n.

Indoxyl glycosides are well-established and widely used tools for enzyme screening and enzyme activity monitoring. Especially for glucose type structures previous syntheses proved to be challenging and low yielding. Our novel approach employs indoxylic acid esters as precious intermediates to yield a considerable number of indoxyl glycosides in good yields.

Synthese von Indoxyl-Glykoside zum Nachweis von Glycosidase Aktivitäten

Indoxyl glycosides proved to be valuable and versatile tools for monitoring glycosidase activities. Indoxyls are released by enzymatic hydrolysis and are ...

High-throughput Synthesis of Carbohydrates and Functionalization of Polyanhydride Nanoparticles

Transdisciplinary approaches involving areas such as material design, nanotechnology, chemistry, and immunology have to be utilized to rationally design efficacious vaccines carriers. Nanoparticle-based platforms can prolong the persistence of vaccine antigens, which could improve vaccine immunogenicity1. Several biodegradable polymers have been studied as vaccine delivery vehicles1; in particular, polyanhydride particles have demonstrated the ability to provide sustained release of stable protein antigens and to activate antigen presenting cells and modulate immune responses2-12.
The molecular design of these vaccine carriers needs to integrate the rational selection of polymer properties as well as the incorporation of appropriate targeting agents. High throughput automated fabrication of targeting ligands and functionalized particles is a powerful tool that will enhance the ability to study a wide range of properties and will lead to the design of reproducible vaccine delivery devices.
The addition of targeting ligands capable of being recognized by specific receptors on immune cells has been shown to modulate and tailor immune responses10,11,13 C-type lectin receptors (CLRs) are pattern recognition receptors (PRRs) that recognize carbohydrates present on the surface of pathogens. The stimulation of immune cells via CLRs allows for enhanced internalization of antigen and subsequent presentation for further T cell activation14,15. Therefore, carbohydrate molecules play an important role in the study of immune responses; however, the use of these biomolecules often suffers from the lack of availability of structurally well-defined and pure carbohydrates. An automation platform based on iterative solution-phase reactions can enable rapid and controlled synthesis of these synthetically challenging molecules using significantly lower building block quantities than traditional solid-phase methods16,17.
Herein we report a protocol for the automated solution-phase synthesis of oligosaccharides such as mannose-based targeting ligands with fluorous solid-phase extraction for intermediate purification. After development of automated methods to make the carbohydrate-based targeting agent, we describe methods for their attachment on the surface of polyanhydride nanoparticles employing an automated robotic set up operated by LabVIEW as previously described10. Surface functionalization with carbohydrates has shown efficacy in targeting CLRs10,11 and increasing the throughput of the fabrication method to unearth the complexities associated with a multi-parametric system will be of great value (Figure 1a).

In this article, a high throughput method is presented for the synthesis of oligosaccharides and their attachment to the surface of polyanhydride nanoparticles for further use in targeting specific receptors on antigen presenting cells.

Hochdurchsatz-Synthese von Kohlenhydraten und Funktionalisierung von Nanopartikeln Polyanhydrid

Transdisciplinary approaches involving areas such as material design, nanotechnology, chemistry, and immunology have to be utilized to rationally design ...

Biotechnik

Chemo-enzymatic Synthesis of N-glycans for Array Development and HIV Antibody Profiling

We present a highly efficient way for the rapid preparation of a wide range of N-linked oligosaccharides (estimated to exceed 20,000 structures) that are commonly found on human glycoproteins. To achieve the desired structural diversity, the strategy began with the chemo-enzymatic synthesis of three kinds of oligosaccharyl fluoride modules, followed by their stepwise &#945;-selective glycosylations at the 3-O and 6-O positions of the mannose residue of the common core trisaccharide having a crucial &#946;-mannoside linkage. We further attached the N-glycans to the surface of an aluminum oxide-coated glass (ACG) slide to create a covalent mixed array for the analysis of hetero-ligand interaction with an HIV antibody. In particular, the binding behavior of a newly isolated HIV-1 broadly neutralizing antibody (bNAb), PG9, to the mixture of closely spaced Man5GlcNAc2 (Man5) and 2,6-di-sialylated bi-antennary complex type N-glycan (SCT) on an ACG array, opens a new avenue to guide the effective immunogen design for HIV vaccine development. In addition, our ACG array embodies a powerful tool to study other HIV antibodies for hetero-ligand binding behavior.

Chemo-enzymatic Synthesis of N-glycans for Array Development and HIV Antibody Profiling

A modular approach to the synthesis of N-glycans for attachment to an aluminum oxide-coated glass slide (ACG slide) as a glycan microarray has been developed and its use for the profiling of an HIV broadly neutralizing antibody has been demonstrated.

Chemo-enzymatische Synthese von N- Glykanen für Array-Entwicklung und HIV-Antikörper-Profiling

We present a highly efficient way for the rapid preparation of a wide range of N-linked oligosaccharides (estimated to exceed 20,000 structures) that are ...

Protocol for the Solid-phase Synthesis of Oligomers of RNA Containing a 2'-O-thiophenylmethyl Modification and Characterization via Circular Dichroism

Solid-phase synthesis has been used to obtain canonical and modified polymers of nucleic acids, specifically of DNA or RNA, which has made it a popular methodology for applications in various fields and for different research purposes. The procedure described herein focuses on the synthesis, purification, and characterization of dodecamers of RNA 5&#39;-[CUA CGG AAU CAU]-3&#39; containing zero, one, or two modifications located at the C2&#39;-O-position. The probes are based on 2-thiophenylmethyl groups, incorporated into RNA nucleotides via standard organic synthesis and introduced into the corresponding oligonucleotides via their respective phosphoramidites. This report makes use of phosphoramidite chemistry via the four canonical nucleobases (Uridine (U), Cytosine (C), Guanosine (G), Adenosine (A)), as well as 2-thiophenylmethyl functionalized nucleotides modified at the 2&#39;-O-position; however, the methodology is amenable for a large variety of modifications that have been developed over the years. The oligonucleotides were synthesized on a controlled-pore glass (CPG) support followed by cleavage from the resin and deprotection under standard conditions, i.e., a mixture of ammonia and methylamine (AMA) followed by hydrogen fluoride/triethylamine/N-methylpyrrolidinone. The corresponding oligonucleotides were purified via polyacrylamide electrophoresis (20% denaturing) followed by elution, desalting, and isolation via reversed-phase chromatography (Sep-pak, C18-column). Quantification and structural parameters were assessed via ultraviolet-visible (UV-vis) and circular dichroism (CD) photometric analysis, respectively. This report aims to serve as a resource and guide for beginner and expert researchers interested in embarking in this field. It is expected to serve as a work-in-progress as new technologies and methodologies are developed. The description of the methodologies and techniques within this document correspond to a DNA/RNA synthesizer (refurbished and purchased in 2013) that uses phosphoramidite chemistry.

Protocol for the Solid-phase Synthesis of Oligomers of RNA Containing a 2'-O-thiophenylmethyl Modification and Characterization via Circular Dichroism

This article provides a detailed procedure on the solid-phase synthesis, purification, and characterization of dodecamers of RNA modified at the C2&#39;-O-position. UV-vis and circular dichroism photometric analyses are used to quantify and characterize structural aspects, i.e., single-strands or double-strands.

Protokoll für die Festphasensynthese von Oligomeren der RNA mit einem 2&#39;-<em&gt; O</em&gt; -thiophenylmethyl-Modifikation und Charakterisierung über Kreisdichroismus

Solid-phase synthesis has been used to obtain canonical and modified polymers of nucleic acids, specifically of DNA or RNA, which has made it a popular ...

One-pot Microwave-assisted Conversion of Anomeric Nitrate-esters to Trichloroacetimidates

The goal of the following procedure is to provide a demonstration of the one-pot conversion of a 2-azido-1-nitrate-ester to a trichloroacetimidate glycosyl donor. Following azido-nitration of a glycal, the product 2-azido-1-nitrate ester can be hydrolyzed under microwave-assisted irradiation. This transformation is usually achieved using strongly nucleophilic reagents and extended reaction times. Microwave irradiation induces hydrolysis, in the absence of reagents, with short reaction times. Following denitration, the intermediate anomeric alcohol is converted, in the same pot, to the corresponding 2-azido-1-trichloroacetimidate.

A 2-azido-1-nitrate-ester can be converted to the corresponding 2-azido-1-trichloroacetimidate in a one-pot procedure. The goal of the manuscript is to demonstrate utility of the microwave reactor in carbohydrate synthesis.

Ein-Topf Mikrowellen-gestützte Umwandlung des Anomeric Nitrat-Ester und Trichloroacetimidates

The goal of the following procedure is to provide a demonstration of the one-pot conversion of a 2-azido-1-nitrate-ester to a trichloroacetimidate ...

Hierarchical and Programmable One-Pot Oligosaccharide Synthesis

This article presents a general experimental protocol for programmable one-pot oligosaccharide synthesis and demonstrates how to use Auto-CHO software for generating potential synthetic solutions. The programmable one-pot oligosaccharide synthesis approach is designed to empower fast oligosaccharide synthesis of large amounts using thioglycoside building blocks (BBLs) with the appropriate sequential order of relative reactivity values (RRVs). Auto-CHO is a cross-platform software with a graphical user interface that provides possible synthetic solutions for programmable one-pot oligosaccharide synthesis by searching a BBL library (containing about 150 validated and &#62;50,000 virtual BBLs) with accurately predicted RRVs by support vector regression. The algorithm for hierarchical one-pot synthesis has been implemented in Auto-CHO and uses fragments generated by one-pot reactions as new BBLs. In addition, Auto-CHO allows users to give feedback for virtual BBLs to keep valuable ones for further use. One-pot synthesis of stage-specific embryonic antigen 4 (SSEA-4), which is a pluripotent human embryonic stem cell marker, is demonstrated in this work.

This protocol demonstrates how to use the Auto-CHO software for hierarchical and programmable one-pot synthesis of oligosaccharides. It also describes the general procedure for RRV determination&#160;experiments and one-pot glycosylation of SSEA-4.

Hierarchische und programmierbare Ein-Topf-Oligosaccharid-Synthese

This article presents a general experimental protocol for programmable one-pot oligosaccharide synthesis and demonstrates how to use Auto-CHO software for ...

Synthesis of Information-bearing Peptoids and their Sequence-directed Dynamic Covalent Self-assembly

This protocol presents the use of Lewis acidic multi-role reagents to circumvent kinetic trapping observed during the self-assembly of information-encoded oligomeric strands mediated by paired dynamic covalent interactions in a manner mimicking the thermal cycling commonly employed for the self-assembly of complementary nucleic acid sequences. Primary amine monomers bearing aldehyde and amine pendant moieties are functionalized with orthogonal protecting groups for use as dynamic covalent reactant pairs. Using a modified automated peptide synthesizer, the primary amine monomers are encoded into oligo(peptoid) strands through solid-phase submonomer synthesis. Upon purification by high-performance liquid chromatography (HPLC) and characterization by electrospray ionization mass spectrometry (ESI-MS), sequence-specific oligomers are subjected to high-loading of a Lewis acidic rare-earth metal triflate which both deprotects the aldehyde moieties and affects the reactant pair equilibrium such that strands completely dissociate. Subsequently, a fraction of the Lewis acid is extracted, enabling annealing of complementary sequence-specific strands to form information-encoded molecular ladders characterized by matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS). The simple procedure outlined in this report circumvents kinetic traps commonly experienced in the field of dynamic covalent assembly and serves as a platform for the future design of robust, complex architectures.

A protocol is presented for the synthesis of information-encoded peptoid oligomers and for the sequence-directed self-assembly of these peptoids into molecular ladders using amines and aldehydes as dynamic covalent reactant pairs and Lewis acidic rare-earth metal triflates as multi-role reagents.

Synthese von informationstragenden Peptoiden und deren sequenzgesteuerter dynamischer kovalenter Selbstmontage

This protocol presents the use of Lewis acidic multi-role reagents to circumvent kinetic trapping observed during the self-assembly of information-encoded ...

Chemical Triphosphorylation of Oligonucleotides

The 5&#8242;-triphosphate is an essential nucleic acid modification found throughout all life and increasingly used as a functional modification of oligonucleotides in biotechnology and synthetic biology. Oligonucleotide 5&#8242;-triphosphates have historically been prepared in vitro by enzymatic methods. However, these methods are limited to natural RNA oligonucleotides, have strong sequence preferences, and tend to produce heterogeneous products. New methods of chemical triphosphorylation complement both the reduced cost of automated oligonucleotide synthesis by phosphoramidite chemistry and the diverse range of nucleotide modifications now available. Thus, the synthesis of oligonucleotide triphosphates of arbitrary sequence and length, and optionally containing various nonnatural modifications, is now accessible.
This paper presents the appropriate methods and techniques for chemical triphosphorylation of oligonucleotides using salicyl phosphorochloridite and pyrophosphate. This method uses commercially available reagents, is compatible with most oligonucleotides prepared by standard solid-phase synthesis methods, and can be completed in 2 h following oligonucleotide synthesis, before deprotection and purification. Two uses of chemically triphosphorylated oligonucleotides as substrates for catalytic RNA enzymes are demonstrated, including the synthesis of a mirror-image version of the hammerhead ribozyme from nonbiological L-RNA triphosphates.

Oligonucleotide 5&#8242;-triphosphates are ubiquitous components in essential biological pathways and have seen increasing use in biotechnology applications. Here, we describe techniques for the routine synthesis and purification of oligonucleotide 5&#8242;-triphosphates, starting from oligonucleotides prepared by standard automated synthesis techniques.

Chemische Triphosphorylierung von Oligonukleotiden

The 5&#8242;-triphosphate is an essential nucleic acid modification found throughout all life and increasingly used as a functional modification of ...

<meta charset="utf8"></head><body>Expansionsmikroskopie zur Visualisierung intrazellulärer sialylierter Glykane mittels MOE

Visualizing Intracellular Sialylation with Click Chemistry and Expansion Microscopy

Metabolic labeling techniques allow the incorporation of bioorthogonal reporters into glycans, enabling the targeted bioconjugation of molecular dyes within cells through click and bioorthogonal chemistry. Metabolic oligosaccharide engineering (MOE) has attracted considerable interest due to the essential role of glycosylation in numerous biological processes that involve molecular recognition and its impact on pathologies ranging from cancer to genetic disorders to viral and bacterial infections.
Although MOE is better known for the detection of cell surface glycoconjugates, it is also a very important methodology for the study of intracellular glycans in physiological and pathological contexts. Such studies greatly benefit from high spatial resolution. However, super-resolution microscopy is not readily available in most laboratories and poses challenges for daily implementation. Expansion microscopy is a recent alternative that enhances the resolution of microscopy by physically enlarging biological specimens labeled with fluorescent markers. By embedding the sample in a swellable gel and causing it to expand isotropically through chemical treatment, subcellular structures can be visualized with enhanced precision and resolution without the need for super-resolution techniques.
In this work, we illustrate the capacity of expansion microscopy to visualize intracellular sialylated glycans through the combined use of MOE and click chemistry. Specifically, we propose a procedure for bioorthogonal labeling and expansion microscopy that employs a reporter targeting sialylation, which may be associated with immunofluorescence for co-localization studies. This protocol enables localization studies of sialoconjugate biosynthesis, intracellular trafficking, and recycling.

<meta charset="utf8"></head><body>Visualisierung der intrazellulären Sialylierung mit Click-Chemie und Expansionsmikroskopie

Here, we propose a simple protocol combining metabolic oligosaccharide engineering, click chemistry, and expansion microscopy that allows bioimaging of intracellular sialylated N-glycoproteins with improved resolution using routine microscopy equipment.

Visualisierung der intrazellulären Sialylierung mit Click-Chemie und Expansionsmikroskopie

Metabolic labeling techniques allow the incorporation of bioorthogonal reporters into glycans, enabling the targeted bioconjugation of molecular dyes ...