Biosynthesis of acetylacetone inspired by its biodegradation

Enhanced Thermostability of Nattokinase by Computation-Based Rational Redesign of Flexible Regions

Nattokinase is a nutrient in healthy food natto that has the function of preventing and treating blood thrombus. However, its low thermostability and fibrinolytic activity limit its application in food and pharmaceuticals. In this study, we used bioinformatics analysis to identify two loops (loop10 and loop12) in the flexible region of nattokinase rAprY. Using this basis, we screened the G131S-S161T variant, which showed a 2.38-fold increase in half-life at 55 °C, and the M3 variant, which showed a 2.01-fold increase in activity, by using a thermostability prediction algorithm. Bioinformatics analysis revealed that the enhanced thermostability of the G131S-S161T variant was due to the increased rigidity and structural shrinkage of the overall structure. Additionally, the increased rigidity of the local region surrounding the active center and its mutated sites helps maintain its normal conformation in high-temperature environments. The increased catalytic activity of the M3 variant may be due to its more efficient substrate binding mechanism. We investigated strategies to improve the thermostability and fibrinolytic activity of nattokinase, and the resulting variants show promise for industrial production and application.

Lanthanide-based metal-organic framework materials as bifunctional fluorescence sensors toward acetylacetone and aspartic acid

A family of novel lanthanide-based metal-organic frameworks (Ln-MOFs) with bifunctional fluorescence sensing, namely {[(CH3)2NH2]5[Ln5(TBAPy)5]•solvent}n (Ln = Gd (1), Tb (2), and Dy (3), H4TBAPy = 1,3,5,7-tetra(4-carboxybenzene)pyrene), have been synthesized and...

In Vitro Biosynthesis of Isobutyraldehyde Through the Establishment of a One-Step Self-Assembly-Based Immobilization Strategy

The in vitro biosynthesis of high-value compounds has become popular and attractive. The convenient and simple strategy of enzyme immobilization has been significant for continuous and efficient in vitro biosynthesis. On the basis of that, this work established a one-step self-assembly-based immobilization strategy to efficiently biosynthesize isobutyraldehyde in vitro. Isobutyraldehyde is a crucial precursor for the synthesis of foods and spices. The established CipA scaffold-based strategy can express and immobilize enzymes at the same time, and purification requires only one centrifugation step. Structural simulations indicated that this scaffold-dependent self-assembly did not influence the structure or catalytic mechanisms of the isobutyraldehyde production-related enzymes leucine dehydrogenase (LeuDH) and ketoisovalerate decarboxylase (Kivd). Immobilized LeuDH and Kivd displayed a higher conversion capacity and thermal stability than the free enzymes. Batch conversion experiments demonstrated that the recovered immobilized LeuDH and Kivd have similar conversion capacities to the enzymes used in the first round of reaction. The continuous production of isobutyraldehyde was achieved by filling the immobilized enzymes into the column of a constructed device. This study not only expands the application range of self-assembly systems but also provides guidance for the in vitro production of value-added compounds.