1.Synthesis and plant growth regulation activity of α-d-ManpNAc-(1→2)-[α-L-Rhap-(1→3)-]α-L-Rhap-(1→4)-β-d-GlupNAc-(1→3)-α-L-Rhap, the repeating unit of O-antigen of Rhizobium trifolii 4s.
Zong G1, Liang X1, Zhang J2, Duan L3, Tan W4, Wang D1. Carbohydr Res. 2014 Mar 31;388:87-93. doi: 10.1016/j.carres.2013.12.006. Epub 2013 Dec 12.
The synthesis of a pentasaccharide 2 containing acetamido-2-deoxy-d-glucose and acetamido-2-deoxy-d-mannose related to the cell wall polysaccharide of Rhizobium trifolii 4s has been achieved by a [2+3] approach from commercially available l-rhamnose, d-glucose, and d-glucosamine as the starting materials. The target molecule was equipped with a p-methoxylphenyl handle at the reducing terminus to allow for further glycoconjugate formation via selective cleavage of this group. The bioassay suggested that the synthetic pentasaccharide 2 can stimulate the growth of wheat coleoptile similarly to indole-3-acetic acid (IAA), and promote the wheat seedling development before winter by seed treatment at a concentration of 20mg/L.
2.Hydroxyl distribution in sugar structure and its contributory role in the inhibition of Stachybotrys microspora β-glucosidase (bglG).
Saibi W1, Gargouri A. Carbohydr Res. 2011 Sep 27;346(13):1848-54. doi: 10.1016/j.carres.2011.06.016. Epub 2011 Jul 19.
Stachybotrys microspora is a filamentous fungus that produces various β-glucosidases, of which two have already been characterized. The present study reports on the production of a third one, named bglG, in the presence of d-glucose used as a sole carbon source, and on its subsequent purification and characterization. Although efficiently produced in the presence of d-glucose, bglG continues to be highly inhibited by this sugar. In fact, the addition of d-glucose significantly decreases the glucose formation rates during the hydrolysis of pNPG. This work reports on the effect of various carbohydrates on bglG activity in order to understand the mechanisms adopted by d-glucose to inhibit this enzyme. The findings indicate that bglG is strongly inhibited by d-glucose (44% of the relative activity at 5mM), d-glucitol (96% of the relative activity), d-mannose (56% of the relative activity), cellobiose and maltose (72% and 71% of the relative activity, respectively).
3.The structure of the wall teichoic acid isolated from Enterococcus faecalis strain 12030.
Theilacker C1, Holst O, Lindner B, Huebner J, Kaczyński Z. Carbohydr Res. 2012 Jun 1;354:106-9. doi: 10.1016/j.carres.2012.03.031. Epub 2012 Apr 3.
Wall teichoic acid (WTA) was isolated from Enterococcus faecalis 12030, a clinical isolate and biofilm-producing strain, and analyzed using compositional chemical methods, nuclear magnetic resonance spectroscopy, and mass spectrometry. The repeating units of WTA were composed of D-glucose, D-galactose, 2-acetamido-2-deoxy-D-galactose, 2-acetamido-2-deoxy-D-glucose, D-ribitol, and phosphate in a molar ratio 1:2:1:1:1:1, and had the structure given below.
4.One-pot enzymatic production of 2-acetamido-2-deoxy-D-galactose (GalNAc) from 2-acetamido-2-deoxy-D-glucose (GlcNAc).
Inoue K1, Nishimoto M, Kitaoka M. Carbohydr Res. 2011 Nov 8;346(15):2432-6. doi: 10.1016/j.carres.2011.08.032. Epub 2011 Sep 8.
2-Acetamido-2-deoxy-D-galactose (GalNAc) is a common monosaccharide found in biologically functional sugar chains, but its availability is often limited due to the lack of abundant natural sources. In order to produce GalNAc from abundantly available sugars, 2-acetamido-2-deoxy-D-glucose (GlcNAc) was converted to GalNAc by a one-pot reaction using three enzymes involved in the galacto-N-biose/lacto-N-biose I pathway of bifidobacteria. Starting the reaction with 600 mM GlcNAc, 170 mM GalNAc was produced at equilibrium in the presence of catalytic amounts of ATP and UDP-Glc under optimized conditions. GalNAc was separated from GlcNAc using water-eluting cation-exchange chromatography with a commonly available cation-exchange resin.