- Synthesis of Functionalized N-Acetyl Muramic Acids to Probe Bacterial Cell Wall Recycling and Biosynthesis
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Uridine diphosphate N-acetyl muramic acid (UDP NAM) is a critical intermediate in bacterial peptidoglycan (PG) biosynthesis. As the primary source of muramic acid that shapes the PG backbone, modifications installed at the UDP NAM intermediate can be used to selectively tag and manipulate this polymer via metabolic incorporation. However, synthetic and purification strategies to access large quantities of these PG building blocks, as well as their derivatives, are challenging. A robust chemoenzymatic synthesis was developed using an expanded NAM library to produce a variety of 2-N-functionalized UDP NAMs. In addition, a synthetic strategy to access bio-orthogonal 3-lactic acid NAM derivatives was developed. The chemoenzymatic UDP synthesis revealed that the bacterial cell wall recycling enzymes MurNAc/GlcNAc anomeric kinase (AmgK) and NAM α-1 phosphate uridylyl transferase (MurU) were permissive to permutations at the two and three positions of the sugar donor. We further explored the utility of these derivatives in the fluorescent labeling of both Gram (-) and Gram (+) PG in whole cells using a variety of bio-orthogonal chemistries including the tetrazine ligation. This report allows for rapid and scalable access to a variety of functionalized NAMs and UDP NAMs, which now can be used in tandem with other complementary bio-orthogonal labeling strategies to address fundamental questions surrounding PG's role in immunology and microbiology.
- Demeester, Kristen E.,Liang, Hai,Jensen, Matthew R.,Jones, Zachary S.,D'Ambrosio, Elizabeth A.,Scinto, Samuel L.,Zhou, Junhui,Grimes, Catherine L.
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supporting information
p. 9458 - 9465
(2018/07/21)
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- Exploring the Structural Space of the Galectin-1–Ligand Interaction
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Galectin-1 is a tumor-associated protein recognizing the Galβ1-4GlcNAc motif of cell-surface glycoconjugates. Herein, we report the stepwise expansion of a multifunctional natural scaffold based on N-acetyllactosamine (LacNAc). We obtained a LacNAc mimeti
- Bertleff-Zieschang, Nadja,Bechold, Julian,Grimm, Clemens,Reutlinger, Michael,Schneider, Petra,Schneider, Gisbert,Seibel, Jürgen
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p. 1477 - 1481
(2017/08/10)
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- Linear synthesis of the branched pentasaccharide repeats of O-antigens from Shigella flexneri 1a and 1b demonstrating the major steric hindrance associated with type-specific glucosylation
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Shigella flexneri serotypes 1b and 1a are Gram-negative enteroinvasive bacteria causing shigellosis in humans. The O-antigen from S. flexneri 1b is a {→2)-[3Ac/4Ac]-α-l-Rhap-(1→2)-α-l-Rhap-(1→3)-[2Ac]-α-l-Rhap-(1→3)-[α-d-Glcp-(1→4)]-β-d-GlcpNAc-(1→}n branched polysaccharide ({AcABAcC(E)D}n). It is identical to that from S. flexneri 1a, except for the 2C-acetate. A concise synthesis of the disaccharide ED, trisaccharides AcC(E)D and C(E)D, tetrasaccharides BAcC(E)D and BC(E)D, and pentasaccharides ABAcC(E)D and ABC(E)D is described starting from a 2-N-acetyl-d-glucosaminide acceptor and using the imidate glycosylation chemistry. The E residue was efficiently introduced via a potent stereoselective [E + D] coupling. In contrast, harsh conditions and appropriate tuning of the donor were required for a high yielding [C + ED] glycosylation. Irrespective of the level of steric bulk at residue C, glycosylation at O-3D of the ED acceptor generated a major change of conformation of the D residue within the obtained C(E)D trisaccharide, as attested by NMR data. Proper manipulation of the constrained C(E)D trisaccharide was necessary to proceed with the stepwise chain elongation at O-3C of an acceptor having the 2C-O-acetyl already in place. The protected intermediates went through a one- to three-step deprotection sequence to give the propyl glycoside targets, as portions of the O-antigens from both S. flexneri 1a and 1b. Protecting group removal was clearly associated with conformational relief, yielding oligosaccharides, for which NMR data were consistent with a 4C1 conformation for the 3,4-di-O-glycosylated residue D, as in the native bacterial polymers.
- Hargreaves, Jason M.,Le Guen, Yann,Guerreiro, Catherine,Descroix, Karine,Mulard, Laurence A.
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p. 7728 - 7749
(2015/01/08)
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- Stereoselective dihydroxylation reaction of alkenyl β- D -hexopyranosides: A methodology for the synthesis of glycosylglycerol derivatives and 1-O-Acyl-3-O-β- D -glycosyl-sn-glycerol analogues
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A variety of new glycosylglycerol derivatives have been prepared by stereoselective dihydroxylation of a range of alkenyl β-D-hexopyanosides under Donohoe's conditions. We have studied the relationship between the diastereoisomeric excess and the structural features of the precursor (sugar and alkenyl moieties). The stereochemical yields demonstrated that the presence of a hydrogen-bond donor group (OH, NHAc) at the 2-position of the sugar moiety is required to obtain high levels of stereofacial discrimination. New 1-O-acyl-3-O-β-D-glycosyl-sn-glycerol analogues were obtained by functionalisation of the primary hydroxy group with a fatty acid. Preliminary cytotoxic activity assays of both glycosylglycerol and glycoglycerolipid analogues are also presented. An efficient asymmetric dihydroxylation reaction of alkenyl β-D-hexopyranoside derivatives is described. New glycosylglycerol and glycoglycerolipid analogues have been synthesised by this methodology. Preliminary cytotoxic activity assays are presented. Copyright
- Vega-Perez, Jose M.,Palo-Nieto, Carlos,Perinan, Ignacio,Vega-Holm, Margarita,Calderon-Montano, Jose M.,Lopez-Lazaro, Miguel,Iglesias-Guerra, Fernando
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experimental part
p. 1237 - 1252
(2012/04/10)
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- SYNTHESIS OF CORE SUGAR CHAIN STRUCTURE OF ASPARGINE-LINKED GLYCOPROTEIN
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It is intended to chemically synthesize the trisaccharide moiety at the reducing end in the core sugar chain structure of an asparagine-linked glycoprotein. By using a highly inexpensive natural polysaccharide having a mannose β-1,4-bond as the starting m
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Page/Page column 15-16
(2008/06/13)
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- Synthesis and biological activities of lipid A analogs possessing β-glycosidic linkage at 1-position
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New lipid A analogs having acidic groups β-glycosidically linked at the 1-position were synthesized in order to investigate the structural requirement for immunostimulating and endotoxic activity of lipid A. The β-(phosphonoxy)ethyl (PE) and carboxymethyl (CM) analogs of Escherichia coli type having six acyl groups and those of the biosynthetic precursor type having four acyl groups were synthesized via a divergent synthetic route. The E. coli type β-(phosphonoxy)-ethyl analog, which was previously reported to be not endotoxic, showed strong immunostimulating activity comparable to the natural-type α-analog. The acidic functional groups are concluded to be essential but their strict spatial arrangement is not required for expression of the biological activity.
- Fukase, Koichi,Ueno, Atsushi,Fukase, Yoshiyuki,Oikawa, Masato,Suda, Yasuo,Kusumoto, Shoichi
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p. 485 - 500
(2007/10/03)
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- Stereoselective synthesis of epoxyalkyl glycoside precursors of glycosyl glycerol analogues from alkenyl glycosides of N-acetyl-D-glucosamine derivatives
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The synthesis of epoxyalkyl glycoside derivatives of N-acetyl-D-glucosamine is described. Epoxidation of the corresponding alkenyl glycosides with m-CPBA took place with different stereoselectivity depending on the nature of the unsaturated system and the protecting groups on the sugar moiety. The configuration of the newly formed stereogenic centres has been confirmed unequivocally by chemical correlation.
- Vega-Perez, Jose M.,Candela, Jose I.,Blanco, Eugenia,Iglesias-Guerra, Fernando
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p. 2471 - 2483
(2007/10/03)
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- TMSCl as a mild and effective source of acidic catalysis in Fischer glycosidation and use of propargyl glycoside for anomeric protection
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Practical Fischer glycosidation was effected at room temperature or 60°C by using 5 to 10 equiv. of TMSCl. The anomeric propargyl group formed by this method was found to be a versatile new protecting group, being stable in neat TFA but readily cleaved by treatment with Co2(CO)8 and TFA in CH2Cl2 via the formation of an alkyne-Co complex.
- Izumi, Minoru,Fukase, Koichi,Kusumoto, Shoichi
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p. 211 - 214
(2007/10/03)
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- Conformational differences between Fuc(α1-3)GlcNAc and its thioglycoside analogue
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NOE measurements and molecular mechanics calculations have been performed to study the conformational behaviour of Fuc(α1-3)GlcNAc and its thioglycoside analogue in solution. Experimental data show that, in contrast with the natural O-disaccharide, which
- Aguilera, Begona,Jimenez-Barbero, Jesus,Fernandez-Mayoralas, Alfonso
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- Glycosylidene Carbenes Part 4 Synthesis of Spirocyclopropanes from Acetamidoglycosylidene-Derived Diazirines
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The synthesis of the first glycosylidene-derived 2-acetamido-2-deoxydiazirine 4 from N-acetylglucosamine 6 is described.Thus, 6 was transformed into the 3-O-mesylglucopyranoside 9 by glycosidation with allyl alcohol, benzylidenation, and mesylation (Schem
- Vasella, Andrea,Witzig, Christian,Husi, Rene
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p. 1362 - 1372
(2007/10/02)
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- 1,3,4,6-Tetra-O-acetyl-2-chloroacetamido-2-deoxy-β-D-glucopyranose as a glycosyl donor in syntheses of oligosaccharides
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1,3,4,6-Tetra-O-acetyl-2-chloroacetamido-2-deoxy-β-D-glucopyranose was tested as a glycosyl donor for oligosaccharide synthesis via ferric chloride-catalyzed coupling reaction.Glycosyl acceptors tried (6 in all) were O-benzyl-protected D-galactosides having free OH groups at positions 3 and 4, respectively, and similarly protected glycosides of D-glucose and 2-acetamido-2-deoxy-D-glucose unsubstituted on O-4.Existing syntheses of all the acceptors were improved, in four instances by exploitation of Garegg and Hultberg's cyanoborohydride procedure for the conversion 4,6-O-benzylidene -> 6-O-benzyl .Good to excellent yields of β-linked disaccharides were obtained from the galactoside and glucoside acceptors, but with allyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-α-D-glucopyranoside, stereoselectivity was lost (α:β-ratio 1:2).Allyl and benzyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-β-D-glucopyranosides gave, respectively, the allyl and benzyl β-glycosides of the donor as major products.A mechanism is proposed for this transglycosidation reaction.The N-chloroacetyl groups in the disaccharide products were readily converted into N-acetyl by reduction with zinc-acetic acid.
- Dasgupta, Falguni,Anderson, Laurens
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p. 239 - 255
(2007/10/02)
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