136845-44-8Relevant articles and documents
Synthesis of Functionalized N-Acetyl Muramic Acids to Probe Bacterial Cell Wall Recycling and Biosynthesis
Demeester, Kristen E.,Liang, Hai,Jensen, Matthew R.,Jones, Zachary S.,D'Ambrosio, Elizabeth A.,Scinto, Samuel L.,Zhou, Junhui,Grimes, Catherine L.
supporting information, p. 9458 - 9465 (2018/07/21)
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.
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
Hargreaves, Jason M.,Le Guen, Yann,Guerreiro, Catherine,Descroix, Karine,Mulard, Laurence A.
, p. 7728 - 7749 (2015/01/08)
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.
TMSCl as a mild and effective source of acidic catalysis in Fischer glycosidation and use of propargyl glycoside for anomeric protection
Izumi, Minoru,Fukase, Koichi,Kusumoto, Shoichi
, p. 211 - 214 (2007/10/03)
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.
