- Chemoenzymatic synthesis of artificial glycopolypeptides containing multivalent sialyloligosaccharides with a γ-polyglutamic acid backbone and their effect on inhibition of infection by influenza viruses
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Highly water-soluble, artificial glycopolypeptides with a γ-polyglutamic acid (γ-PGA) backbone derived from Bacillus subtilis sp. and multivalent sialyloligosaccharide units have been chemoenzymatically synthesized as potential polymeric inhibitors of infection by bird and human influenza viruses. 5-Trifluoroacetamidopentyl β-N-acetyllactosaminide and 5-trifluoroacetamidopentyl β-lactoside were enzymatically synthesized from LacNAc and lactose, respectively, by cellulase-mediated condensation with 5-trifluoroacetamido-1-pentanol. After deacetylation, the resulting 5-aminopentyl β-LacNAc and β-lactoside glycosides were coupled to the α-carboxyl groups of the γ-PGA side chains. The artificial glycopolypeptides carrying LacNAc and lactose were further converted to Neu5Acα2-(3/6)Galβ1-4Glcβ and Neu5Acα2-(3/6)Galβ1-4GlcNAcβ sialyloligosaccharide units by α2,3- and α2,6-sialyltransferase, respectively. The interaction of these glycopolypeptides with various influenza virus strains has been investigated by three different methods. Glycopolypeptides carrying Neu5Acα2,6LacNAc inhibited hemagglutination mediated by influenza A and B viruses, and their relative binding affinities for hemagglutinin were 102- to 104-fold higher than that of the naturally occurring fetuin control. A glycopolypeptide carrying Neu5Acα2,6LacNAc inhibited infection by A/Memphis/1/71 (H3N2) 93 times more strongly than fetuin, as assessed by cytopathic effects on virus-infected MDCK cells. The avian virus [A/duck/Hong kong/4/78 (H5N3)] bound strongly to Neu5Acα2,3LacNAc/Lac-carrying glycopolypeptides, whereas the human virus [A/Memphis/1/71 (H3N2)] bound to Neu5Acα2,6LacNAc in preference to Neu5Acα2,6Lac. Taken together, these results indicate that the binding of viruses to terminal sialic acids is markedly affected by the structure of the asialo portion, in this case either LacNAc or lactose, in the sugar chain of glycopolypeptides.
- Ogata, Makoto,Murata, Takeomi,Murakami, Kouki,Suzuki, Takashi,Hidari, Kazuya I.P.J.,Suzuki, Yasuo,Usui, Taichi
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- Remote Regioselective Radical C-H Functionalization of Unactivated C-H Bonds in Amides: The Synthesis of gem-Difluoroalkenes
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The site-selective functionalization of unactivated aliphatic amines is an attractive and challenging synthetic approach. We herein report a general strategy for the remote site-selective functionalization of unactivated C(sp3)-H bonds in amides by photogenerated amidyl radicals to form gem-difluoroalkenes with trifluoromethyl-substituted alkenes. The site selectivity is controlled by a 1,5-hydrogen atom transfer (HAT) process of the amide. This photocatalyzed transformation shows both chemo- and site-selectivity, facilitating the formation of a secondary, tertiary, or quaternary carbon center.
- Hu, Qu-Ping,Cheng, Jing,Wang, Ying,Shi, Jie,Wang, Bi-Qin,Hu, Ping,Zhao, Ke-Qing,Pan, Fei
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supporting information
p. 4457 - 4462
(2021/05/26)
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- Rapid Synthesis of Bicyclic N-Heterocyclic Cores from N-Terminal α,β-Unsaturated Diazoketones
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A method for the synthesis of bicyclic N-heterocyclic cores from N-terminal α,β-unsaturated diazoketones has been developed. The transformation involves three sequential steps that include N-deprotection, an intramolecular aza-Michael, and a photochemical Wolff rearrangement as a one-pot protocol. By using this strategy, a series of substituted bicyclic N-heterocycles, particularly, indolizidines and pyrrolizidines, were synthesize in good yields.
- Santiago, Jo?o Victor,Burtoloso, Antonio C. B.
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p. 2822 - 2830
(2018/06/04)
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- METHODS AND COMPOSITIONS RELATING TO BIODEGRADABLE EPOXY ELASTOMERS
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A biodegradable epoxy elastomer comprising a residue of at least one first monomer, the first monomer including a diepoxide; and a residue of at least one second monomer, the second monomer comprising at least one hydrolytically degradable bond.
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Page/Page column 19
(2013/11/05)
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- METHOD FOR DETERMINATION OF RECOGNITION SPECIFICITY OF VIRUS FOR RECEPTOR SUGAR CHAIN
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A method is provided in which the recognition specificity of a virus for a receptor sugar chain can be easily determined with a simple instrument or apparatus. This method for determining the recognition specificity of a virus for a receptor sugar chain or for determining the change in a host infected in accordance with the mutation of virus includes the steps of bringing a sample of the virus into contact with a support having a polymer with sialo-oligosaccharide immobilized on the surface thereof; and assaying the degree of binding therein to determine the recognition specificity of the virus for the receptor sugar chain and to determine the change in a host range. The method is suitable for the surveillance of a virus.
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- Hydrolysis of organophosphorus nerve agent soman by the monoclonal antibodies elicited against an oxyphosphorane hapten
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The antibody-mediated hydrolysis of the nerve agent O-1,2,2-trimethylpropyl methylphosphonofluoridate (soman) 1 has now been established with two monoclonal antibodies raised against the cyclic pentacovalent methyloxyphosphorane hapten 10 that mimics the pentacoordinated trigonal bipyramidal transition-state of the reaction. The hydrolysis reaction was studied using molecular orbital methods at the MP2/6-31 + G*//HF/6-31 + G* level of accuracy. According to the ab initio calculations, the reaction seems to proceed via three separate transition-states. The calculations are in good agreement with the experimental results. The 1,3-dioxabenzophosphole hapten 10 was synthesized, coupled to the carrier protein and the antibodies were obtained by the hybridoma technique. Two antibodies, DB-108P and DB-108Q were found to enhance the rate of soman hydrolysis and they were kinetically characterised.
- Yli-Kauhaluoma, Jari,Humppib, Tarmo,Yliniemelae, Ari
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p. 473 - 479
(2007/10/03)
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- NON-PEPTIDE PEPTIDOMIMETICS
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Compounds are provided which are crossreactive with peptides such as those which bind G-protein-linked receptors, together with preparative and therapeutic methods therefor. The compounds have the general structure: STR1 wherein at least one of R 1, R 2, R. sub.3, R. sub.4, or R 5 comprises a functional group which is chemically similar to that found in the peptide of interest.
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- De novo design and synthesis of somatostatin non-peptide peptidomimetics utilizing β-D-glucose as a novel scaffolding
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Non-peptide peptidomimetics of the peptide hormone somatostatin (SRIF) were designed and synthesized, utilizing β-D-glucose as a novel scaffolding. Such compounds resemble conventional peptide analogs in that they retain critical amino acid side chains bu
- Hirschmann, Ralph,Nicolaou,Pietranico, Sherrie,Leahy, Ellen M.,Salvino, Joseph,Arison, Byron,Cichy, Maria A.,Grant Spoors,Shakespeare, William C.,Sprengeler, Paul A.,Hamley, Peter,Smith III, Amos B.,Reisine, Terry,Raynor, Karen,Maechler, Laurie,Donaldson, Cindy,Vale, Wylie,Freidinger, Roger M.,Cascieri, Margaret R.,Strader, Catherine D.
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p. 12550 - 12568
(2007/10/02)
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