Carbohydrate-binding domains facilitate efficient oligosaccharides synthesis by enhancing mutant catalytic domain transglycosylation activity

Chemoenzymatic approaches using carbohydrate-active enzymes (CAZymes) offer a promising avenue for the synthesis of glycans like oligosaccharides. Here, we report a novel chemoenzymatic route for cellodextrins synthesis employed by chimeric CAZymes, akin to native glycosyltransferases, involving the unprecedented participation of a “non-catalytic” lectin-like domain or carbohydrate-binding modules (CBMs) in the catalytic step for glycosidic bond synthesis using β-cellobiosyl donor sugars as activated substrates. CBMs are often thought to play a passive substrate targeting role in enzymatic glycosylation reactions mostly via overcoming substrate diffusion limitations for tethered catalytic domains (CDs) but are not known to participate directly in any nucleophilic substitution mechanisms that impact the actual glycosyl transfer step. This study provides evidence for the direct participation of CBMs in the catalytic reaction step for β-glucan glycosidic bonds synthesis enhancing activity for CBM-based CAZyme chimeras by >140-fold over CDs alone. Dynamic intradomain interactions that facilitate this poorly understood reaction mechanism were further revealed by small-angle X-ray scattering structural analysis along with detailed mutagenesis studies to shed light on our current limited understanding of similar transglycosylation-type reaction mechanisms. In summary, our study provides a novel strategy for engineering similar CBM-based CAZyme chimeras for the synthesis of bespoke oligosaccharides using simple activated sugar monomers.     

Design and synthesis of novel bis-oximinoalkanoic acids as potent PPARα agonists

Bis-oximinoalkanoic acid derivatives were designed and synthesized to aid in the characterization of selective PPARα agonists by replacing the oxazole ring with flexible oximino group in the lipophilic tail part of a previously reported compound 3. Selected compounds 9d and 9m showed excellent potency and high selectivity towards PPARα in vitro. These compounds found effective in reducing serum triglycerides (TG) in vivo.     

Modulation of PPAR receptor subtype selectivity of the ligands: aliphatic chain vs aromatic ring as a spacer between pharmacophore and the lipophilic moiety

Oxazole containing glycine and oximinobutyric acid derivatives were synthesized as PPARalpha agonists by incorporating polymethylene spacer as a replacement of commonly used phenylene group that connects the acidic head with lipophilic tail. Compound 13a was found to be a selective and potent PPARalpha agonist. Further 1,3-dioxane-2-carboxylic acid derivative 20 was synthesized by replacing the tetramethylene spacer of NS-220, a selective PPARalpha agonist with phenylene group and found to exhibit PPARalpha/gamma dual agonism. These results suggest that compounds possessing polymethylene spacer between pharmacophore and lipophilic tail exhibit predominantly PPARalpha agonism whereas those with an aromatic phenylene spacer shows PPARalpha/gamma dual agonism.     

Validity and reproducibility of arterial pulse wave velocity measurement using new device with oscillometric technique: A pilot study

Background  

Availability of a range of techniques and devices allow measurement of many variables related to the stiffness of large or medium sized arteries. There is good evidence that, pulse wave velocity is a relatively simple measurement and is a good indicator of changes in arterial properties. The pulse wave velocity calculated from pulse wave recording by other methods like doppler or tonometry is tedious, time-consuming and above all their reproducibility depends on the operator skills. It requires intensive resource involvement. For epidemiological studies these methods are not suitable. The aim of our study was to clinically evaluate the validity and reproducibility of a new automatic device for measurement of pulse wave velocity that can be used in such studies.     

Isolation and Characterization of a Chitinase and its cDNA Clone from Rice

A 35 kD chitinase has been purified to apparent homogeneity from extracts of rice bran of cv New Bonnet by ammonium sulfate fractionation, chitin affinity chromatography, cation exchange chromatography on carboxymethyl cellulose and gel filtration. The purified enzyme has an isoelectric point of 8.8. The enzyme inhibited the growth of Rhizoctonia solani (the sheath blight pathogen), Trichoderma viride, T. harzianum, Fusarium graminaerum and F. culmorum in vitro. A cDNA clone for chitinase was isolated from a developing rice seed cDNA library by probing with a barley chitinase cDNA probe. The nucleotide sequence of this 654 bp clone was determined, it contains an open reading frame of 519 nucleotides. The protein product encoded by this clone is homologous to chitinases from tobacco, bean and barley. Southern blot analysis of rice genomic DNA with this probe revealed that chitinases are encoded by a small multi-gene family in the rice genome.     

Discovery of a highly orally bioavailable c-5-[6-(4-Methanesulfonyloxyphenyl)hexyl]-2-methyl-1,3-dioxane-r-2-carboxylic acid as a potent hypoglycemic and hypolipidemic agent

A series of novel 1,3-dioxane-2-carboxylic acid derivatives containing alkyl chain tether and substituted phenyl group as a lipophilic tail have been prepared as agonists of PPARalpha and gamma. c-5-[6-(4-Methanesulfonyloxyphenyl)hexyl]-2-methyl-1,3-dioxane-r-2-carboxylic acid 13c exhibited potent hypoglycemic and lipid lowering activity with high oral bioavailability in animal models.