Dataset Information

Stereoselective Synthesis of 2-Azido-2-deoxy-?-d-mannosides via Cs₂CO₃-Mediated Anomeric O-Alkylation with Primary Triflates: Synthesis of a Tetrasaccharide Fragment of Micrococcus luteus Teichuronic Acid.

ABSTRACT: Cesium carbonate-mediated anomeric O-alkylation of various protected 2-azido-2-deoxy-d-mannoses with primary triflate electrophiles afforded corresponding 2-azido-2-deoxy-?-mannosides in good yields and excellent anomeric selectivity. In addition, 1,3-dibromo-5,5-dimethylhydantoin was found to be the optimal oxidant for preparation of those 2-azido-2-deoxy-d-mannoses from their corresponding thioglycosides. The utilization of this method was demonstrated in the synthesis of a tetrasaccharide fragment of Micrococcus luteus teichuronic acid containing N-acetyl-?-d-mannosaminuronic acid (ManNAcA).

SUBMITTER: Bhetuwal BR

PROVIDER: S-EPMC7799176 | biostudies-literature | 2020 Dec

REPOSITORIES: biostudies-literature

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Stereoselective Synthesis of 2-Azido-2-deoxy-β-d-mannosides via Cs2CO3-Mediated Anomeric O-Alkylation with Primary Triflates: Synthesis of a Tetrasaccharide Fragment of Micrococcus luteus Teichuronic Acid.

Bhetuwal Bishwa Raj BR Wu Fenglang F Meng Shuai S Zhu Jianglong J

The Journal of organic chemistry 20201117 24

Cesium carbonate-mediated anomeric O-alkylation of various protected 2-azido-2-deoxy-d-mannoses with primary triflate electrophiles afforded corresponding 2-azido-2-deoxy-β-mannosides in good yields and excellent anomeric selectivity. In addition, 1,3-dibromo-5,5-dimethylhydantoin was found to be the optimal oxidant for preparation of those 2-azido-2-deoxy-d-mannoses from their corresponding thioglycosides. The utilization of this method was demonstrated in the synthesis of a tetrasaccharide fra ...[more]

PMID: 33201716

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Project description:Dormancy is a protective state in which diverse bacteria, including Mycobacterium tuberculosis, Staphylococcus aureus, Treponema pallidum (syphilis), and Borrelia burgdorferi (Lyme disease), curtail metabolic activity to survive external stresses, including antibiotics. Evidence suggests dormancy consists of a continuum of interrelated states, including viable but nonculturable (VBNC) and persistence states. VBNC and persistence contribute to antibiotic tolerance, reemergence from latent infections, and even quorum sensing and biofilm formation. Previous studies indicate that the protein mechanisms regulating persistence and VBNC states are not well understood. We have queried the VBNC state of Micrococcus luteus NCTC 2665 (MI-2665) by quantitative proteomics combining gel electrophoresis, high-performance liquid chromatography, and tandem mass spectrometry to elucidate some of these mechanisms. MI-2665 is a nonpathogenic actinobacterium containing a small (2.5-Mb), high-GC-content genome which exhibits a well-defined VBNC state induced by nutrient deprivation. The MI-2665 VBNC state demonstrated a loss of protein diversity accompanied by increased levels of 18 proteins that are conserved across actinobacteria, 14 of which have not been previously identified in VNBC. These proteins implicate an anaplerotic strategy in the transition to VBNC, including changes in the glyoxylate shunt, redox and amino acid metabolism, and ribosomal regulatory processes. Our data suggest that MI-2665 is a viable model for dissecting the protein mechanisms underlying the VBNC stress response and provide the first protein-level signature of this state. We expect that this protein signature will enable future studies deciphering the protein mechanisms of dormancy and identify novel therapeutic strategies effective against antibiotic-tolerant bacterial infections.IMPORTANCE Dormancy is a protective state enabling bacteria to survive antibiotics, starvation, and the immune system. Dormancy is comprised of different states, including persistent and viable but nonculturable (VBNC) states that contribute to the spread of bacterial infections. Therefore, it is imperative to identify how bacteria utilize these different dormancy states to survive antibiotic treatment. The objective of our research is to eliminate dormancy as a route to antibiotic tolerance by understanding the proteins that control dormancy in Micrococcus luteus NCTC 2665. This bacterium has unique advantages for studying dormancy, including a small genome and a well-defined and reproducible VBNC state. Our experiments implicate four previously identified and 14 novel proteins upregulated in VBNC that may regulate this critical survival mechanism.

Project description:Aliphatic hydrocarbons are highly appealing targets for advanced cellulosic biofuels, as they are already predominant components of petroleum-based gasoline and diesel fuels. We have studied alkene biosynthesis in Micrococcus luteus ATCC 4698, a close relative of Sarcina lutea (now Kocuria rhizophila), which 4 decades ago was reported to biosynthesize iso- and anteiso-branched, long-chain alkenes. The underlying biochemistry and genetics of alkene biosynthesis were not elucidated in those studies. We show here that heterologous expression of a three-gene cluster from M. luteus (Mlut_13230-13250) in a fatty acid-overproducing Escherichia coli strain resulted in production of long-chain alkenes, predominantly 27:3 and 29:3 (no. carbon atoms: no. C=C bonds). Heterologous expression of Mlut_13230 (oleA) alone produced no long-chain alkenes but unsaturated aliphatic monoketones, predominantly 27:2, and in vitro studies with the purified Mlut_13230 protein and tetradecanoyl-coenzyme A (CoA) produced the same C(27) monoketone. Gas chromatography-time of flight mass spectrometry confirmed the elemental composition of all detected long-chain alkenes and monoketones (putative intermediates of alkene biosynthesis). Negative controls demonstrated that the M. luteus genes were responsible for production of these metabolites. Studies with wild-type M. luteus showed that the transcript copy number of Mlut_13230-13250 and the concentrations of 29:1 alkene isomers (the dominant alkenes produced by this strain) generally corresponded with bacterial population over time. We propose a metabolic pathway for alkene biosynthesis starting with acyl-CoA (or-ACP [acyl carrier protein]) thioesters and involving decarboxylative Claisen condensation as a key step, which we believe is catalyzed by OleA. Such activity is consistent with our data and with the homology (including the conserved Cys-His-Asn catalytic triad) of Mlut_13230 (OleA) to FabH (beta-ketoacyl-ACP synthase III), which catalyzes decarboxylative Claisen condensation during fatty acid biosynthesis.

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Dataset Information

Stereoselective Synthesis of 2-Azido-2-deoxy-?-d-mannosides via Cs₂CO₃-Mediated Anomeric O-Alkylation with Primary Triflates: Synthesis of a Tetrasaccharide Fragment of Micrococcus luteus Teichuronic Acid.

Publications

Stereoselective Synthesis of 2-Azido-2-deoxy-β-d-mannosides via Cs<sub>2</sub>CO<sub>3</sub>-Mediated Anomeric O-Alkylation with Primary Triflates: Synthesis of a Tetrasaccharide Fragment of <i>Micrococcus luteus</i> Teichuronic Acid.

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Dataset Information

Stereoselective Synthesis of 2-Azido-2-deoxy-?-d-mannosides via Cs2CO3-Mediated Anomeric O-Alkylation with Primary Triflates: Synthesis of a Tetrasaccharide Fragment of Micrococcus luteus Teichuronic Acid.

Publications

Stereoselective Synthesis of 2-Azido-2-deoxy-β-d-mannosides via Cs<sub>2</sub>CO<sub>3</sub>-Mediated Anomeric O-Alkylation with Primary Triflates: Synthesis of a Tetrasaccharide Fragment of <i>Micrococcus luteus</i> Teichuronic Acid.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Stereoselective Synthesis of 2-Azido-2-deoxy-?-d-mannosides via Cs₂CO₃-Mediated Anomeric O-Alkylation with Primary Triflates: Synthesis of a Tetrasaccharide Fragment of Micrococcus luteus Teichuronic Acid.