Biocompatible conjugation of Tris base to 2-acetyl and 2-formyl phenylboronic acid.

We describe the biocompatible conjugation of the Tris base to 2-formyl and 2-acetylphenylboronic acid (abbreviated as 2-FPBA and 2-APBA respectively), which have emerged as a versatile chemotype for fast biocompatible conjugation reactions. Tris base was found to react with 2-FPBA/APBA to give oxazolidinoboronate (OzB) complexes, analogous to the thiazolidinoboronate (TzB) and imidazolidinoboronate (IzB) complex formation that we recently reported. The Tris conjugations proceed well in complex biological media, and in contrast to the TzB/IzB complexes, the Tris conjugates exhibit superior kinetic stability (dissociation over days) as well as chemical stability against oxidation. We demonstrate the utility of such conjugation chemistries via a small molecule-induced peptide cyclization in blood serum.

Functional study of a lytic polysaccharide monooxygenase MsLPMO3 from Morchella sextelata in the oxidative degradation of cellulose.

Lytic polysaccharide monooxygenases (LPMOs) can improve the effectiveness with which agricultural waste is utilized. This study described the potent AA9 family protein MsLPMO3, derived from Morchella sextelata. It exhibited strong binding to phosphoric acid swollen cellulose (PASC), and had the considerable binding ability to Cu2+ with a Kd value of 2.70 µM by isothermal titration calorimetry (ITC). MsLPMO3 could also act on PASC at the C1 carbon via MALDI-TOF-MS results. Moreover, MsLPMO3 could boost the hydrolysis efficiency of corncob and wheat bran in combination with glycoside hydrolases. MsLPMO3 also exhibited strong oxidizing ability for 2,6-dimethoxyphenol (2,6-DMP), achieving the best Vmax value of 443.36 U·g-1 for pH 7.4 with a H2O2 concentration of 300 µM. The structure of MsLPMO3 was obtained using AlphaFold2, and the molecular docking results elucidated the specific interactions and key residues involved in the recognition process between MsLPMO3 and cellulose. Altogether, this study expands the knowledge of AA9 family proteins in cellulose degradation, providing valuable insights into the mechanisms of synergistic degradation of lignocellulose with cellulases.

Production and characterization of cellulolytic enzymes from the thermoacidophilic fungal Aspergillus terreus M11 under solid-state cultivation of corn stover.

The production of extracellular cellulases by a newly isolated thermoacidophilic fungus, Aspergillus terreus M11, on the lignocellulosic materials was studied in solid-state fermentation (SSF). The results showed that the high-level cellulase activity was produced at 45 degrees C pH 3 and moisture 80% with corn stover and 0.8% yeast extract as carbon and nitrogen sources. 581 U endoglucanase activity, 243 U filter paper activity and 128 U beta-glucosidase activity per gram of carbon source were obtained in the optimal condition. Endoglucanase and beta-glucosidase exhibited their maximum activity at pH 2 and pH 3, respectively, and both of them showed remarkable stability in the range of pH 2-5. The activities of endoglucanase and beta-glucosidase were up to the maximum at 70 degrees C and maintained about 65% and 53% of their original activities after incubation at 70 degrees C for 6h. The enzyme preparations from this strain were used to hydrolyze Avicel. Higher hydrolysis yields of Avicel were up to 63% on 5% Avicel (w/v) for 72 h with 20 U FPase/g substrate.