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Background Photocontrol of protein activity has become a helpful strategy for regulating biological pathways. Herein, a method for the precise and reversible photocontrol of oxidase activity was developed by using the conformational change of the AsLOV2 domain. Results The AsLOV2 domain was inserted into the nonconserved sites exposed on the surface of the AdhP protein, and the alov9 fusion was successfully screened for subsequent optical experiments under the assumption that neither of these actions affected the original activity of AdhP protein. The activity of alov9 was noticeably inhibited when the fusion was exposed to 470 nm blue light and recovered within 30 min. As a result, we could precisely and reversibly photocontrol alov9 activity through the optimization of several parameters, including cofactor concentration, light intensity, and illumination time. Conclusions An efficient method was developed for the photoinhibition of enzymatic activity based on the insertion of the light-sensitive AsLOV2 domain, providing new ideas for photocontrolling metabolic pathways without carriers in the future.

Objectives: 3,4-Dihydroxybutyric acid (3,4-DHBA) is a multi-functional C4 platform compound with wide applications in the synthesis of materials and pharmaceuticals. Currently, although the biosynthetic pathway for the production of 3,4-DHBA has been developed, low productivity still hampers its use on large scales. Here, a non-natural four-steps biosynthetic pathway was established in recombinant E. coli with a combinatorial strategy.Results: Firstly, several aldehyde dehydrogenases (ALDHs) were screened and characterized for catalyzing the dehydrogenation of 3,4-dihydroxybutanal (3,4-DHB) to 3,4-DHBA through in vitro enzyme assays. Secondly, a recombinant E. coli was successfully constructed to generate 3,4-DHBA from D-xylose by introducing the pathway containing BsGDH, YagF, PpMdlC and ALDH into E. coli with 3.04 g/L 3,4-DHBA obtained. Then, disruption of competing pathways by deleting xylA, ghrA, ghrB and adhP genes contributed to increase the accumulation of 3,4-DHBA by 87%. Final, fusion expression of PpMdlC and YagF resulted in an enhancement of 3,4-DHBA titer (7.71 g/L), as the highest titer reported so far.Conclusions: These results showed that deleting competing pathways and constructing fusion protein could significantly improve the 3,4-DHBA titer in engineered E. coli.

Objective To review the pharmacological characteristics, clinical evidence, and place in therapy of satralizumab for the treatment of neuromyelitis optica spectrum disorders (NMOSDs). Data Sources A comprehensive literature search was conducted in PubMed (January 2000 to October 15, 2020). Key search terms included satralizumab and neuromyelitis optica spectrum disorders. Other sources were derived from product labeling and ClinicalTrials.gov. Study Selection and Data Extraction All English-language articles identified from the data sources were reviewed and evaluated. Phase I, II, and III clinical trials were included. Data Synthesis NMOSD is an autoimmune disease characterized by inflammatory lesions in the optic nerves and spinal cord. Interleukin-6 is involved in the pathogenesis of the disorder. Satralizumab is a humanized monoclonal antibody targeting the interleukin-6 receptor. Phase III trials showed that protocol-defined relapse was 30% for satralizumab and 50% for placebo ( P = 0.018) when patients with NMOSD were treated with satralizumab monotherapy; protocol-defined relapse was 20% for satralizumab and 43% for placebo ( P = 0.02) when satralizumab was added to immunosuppressant treatment. Satralizumab is generally well tolerated, with common adverse effects including injection-related reaction. Relevance to Patient Care and Clinical Practice Satralizumab has the potential to become a valuable treatment option for patients with NMOSD. Conclusion Satralizumab appears to be safe and effective as monotherapy or in combination with an immunosuppressant for patients with NMOSD and has the potential to become a valuable treatment option for these patients.

A cytosolic medium-chain alcohol dehydrogenase Gox0313 from Gluconobacter oxydans DSM2003 was heterologously expressed in Escherichia coli BL21 (DE3) and the resulting proteins were purified and characterized. The recombinant enzyme was confirmed to have a good ability to selectively oxidize the terminal hydroxyl group of varied aliphatic and aromatic diols to the corresponding hydroxyl aldehydes, with no oxidative activities toward hydroxyl aldehydes in the presence of NAD+. This enzyme could not oxidize sec-alcohols. Among the primary diols, ethylene glycol was efficiently converted to glycolaldehyde by Gox0313 coupled with NADH oxidase-2 (NOX-2) from Lactobacillus brevis ATCC367 for NAD+ regeneration. Under the optimal conditions using this enzyme-coupled system (1 U/mL Gox0313 and 4 U/mL NOX-2), 42.32 mM glycolaldehyde was produced from 50 mM ethylene glycol in 8 h with a yield of 83.2%. When the enzyme concentration of Gox0313 was increased to 120 U/mL in the reaction, 500 mM of ethylene glycol was converted to 484.2 mM of glycolaldehyde in 14 h, resulting in a yield of 96.8%. With respect to the superior catalytic activity to primary diols, Gox0313 might be a potentially promising biocatalyst for bioproduction of glycolaldehyde and other hydroxyl aldehydes.

A novel phosphate-solubilizing bacterium HPP16 from plant rhizosphere of Shandong University of Science and Technology districts of Qingdao (China) was isolated and the effects on promoting growth of mung bean (Phaseolus radiatus) seedlings in Campus and Jinshatan; two kinds of acidic soils were studied. HPP16 was identified as Enterobacter asburiae on the basis of 16S rDNA sequencing. It was Indole-3-acetic acid producer, synthesized siderophores and showed acid phosphatase activity. After mung bean was inoculated with HPP16, the germination rate and healthy stand in A-2 (inoculated with fermentation liquid) increased by 26 and 25% compared to A-4 (inoculated with the distilled water; negative control), and were 26 and 31.7% in B-2 (inoculated with fermentation liquid) compared to B-4 (inoculated with the distilled water, negative control). The individual plant height, fresh weight and dry weight in A-2 increased by 7, 10 and 6% compared to A-4, and increased by 8.5, 24 and 9% in B-2 compared to B-4. Mung bean could also increase to absorb K(+), Na(+) and Mg(2+) and improve the production of endogenous indole acetic acid (IAA), and also it reduced the production of abscisic acid (ABA). Findings of this study suggest that HPP16 may be exploited for developing a potential source of biofertilizer.

Background (R)-[3,5-bis(trifluoromethyl)phenyl] ethanol [(R)-3,5-BTPE] is a valuable chiral intermediate for Aprepitant (Emend) and Fosaprepitant (Ivemend). Biocatalyzed asymmetric reduction is a preferred approach to synthesize highly optically active (R)-3,5-BTPE. However, the product concentration and productivity of reported (R)-3,5-BTPE synthetic processes remain unsatisfied. Results A NADPH-dependent carbonyl reductase from Lactobacillus kefir (LkCR) was discovered by genome mining for reduction of 3,5-bis(trifluoromethyl) acetophenone (3,5-BTAP) into (R)-3,5-BTPE with excellent enantioselectivity. In order to synthesize (R)-3,5-BTPE efficiently, LkCR was coexpressed with glucose dehydrogenase from Bacillus subtilis (BsGDH) for NADPH regeneration in Escherichia coli BL21 (DE3) cells, and the optimal recombinant strain produced 250.3 g/L (R)-3,5-BTPE with 99.9% ee but an unsatisfied productivity of 5.21 g/(L h). Then, four different linker peptides were used for the fusion expression of LkCR and BsGDH in E. coli to regulate catalytic efficiency of the enzymes and improved NADPH-recycling efficiency. Using the best strain (E. coli/pET-BsGDH-ER/K(10 nm)-LkCR), up to 297.3 g/L (R)-3,5-BTPE with enantiopurity >99.9% ee was produced via reduction of as much as 1.2 M of substrate with a 96.7% yield and productivity of 29.7 g/(L h). Conclusions Recombinant E. coli/pET-BsGDH-ER/K(10 nm)-LkCR was developed for the bioreduction of 3,5-BTAP to (R)-3,5-BTPE, offered the best results in terms of high product concentration and productivity, demonstrating its great potential in industrial manufacturing of (R)-3,5-BTPE. Electronic supplementary material The online version of this article (doi:10.1186/s12934-016-0585-5) contains supplementary material, which is available to authorized users.