Expression, biochemical characterization, and mutation of a water forming NADH: FMN oxidoreductase from Lactobacillus rhamnosus

Publication date: Available online 17 November 2019Source: Enzyme and Microbial TechnologyAuthor(s): Fei-Long Li, Wen Bin Su, Qing-Lan Tao, Liao-Yuan Zhang, Ye-Wang ZhangAbstractEnzyme-catalyzed cofactor regeneration is a significant approach to avoid large quantities consumption of oxidized cofactor, which is vital in a variety of bioconversion reactions. NADH: FMN oxidoreductase is an ideal regenerating enzyme because innocuous molecular oxygen is required as an oxidant. But the by-product H2O2 limits its further applications at the industrial scale. Here, novel NADH: FMN oxidoreductase (LrFOR) from Lactobacillus rhamnosus comprised of 1146 bp with a predicted molecular weight of 42 kDa was cloned and overexpressed in Escherichia coli BL21 (DE3). Enzyme assay shows that the purified recombinant LrFOR has both the NADPH and NADH oxidation activity. Biochemical characterizations suggested that LrFOR exhibits the specific activity of 39.8 U·mg-1 with the optimal pH and temperature of 5.6 and 35 °C and produces H2O instead of potentially harmful peroxide. To further study its catalytic function, a critical Thr29 residue and its six mutants were investigated. Mutants T29 G, T29A, and T29D show notable enhancement in activities compared with the wild type. Molecular docking of NADH into wild type and its mutants reveal that a small size or electronegative of residue in position29 could shorten the distance of NADH and FMN, promoting the electrons t...
Source: Enzyme and Microbial Technology - Category: Biotechnology Source Type: research

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In conclusion, the results suggest that, because of its bioactivity including the antioxidant, antimicrobial, and enzyme inhibition properties, the D. macrolepis can be accepted as a promising and natural source for the industrial applications. The present study is the first study, in which the bioactive components and the antioxidant, antimicrobial, and enzyme inhibition properties of endemic D. macrolepis plant were determined.
Source: Saudi Pharmaceutical Journal - Category: Drugs & Pharmacology Source Type: research
ConclusionThis study demonstrates that ESAT6 bound with TLR2 can activate iNOS/NO and ROS signalings to reduce the trimethylation of H3K27 resulting in the increment of EMMMs expression that is beneficial to the transition of macrophages into epithelioid macrophages. However, hypoxia can inhibit this transition event. This study has provided new evidence of pathogenesis of granuloma caused by Mtb and also proposed new ideas for the treatment of TB.
Source: Molecular Immunology - Category: Allergy & Immunology Source Type: research
CONCLUSION: Enterococcus spp. with susceptibility to limited antibiotics was one of the main pathogens in Korean IAIs, along with E. coli and Klebsiella spp., which were highly susceptible to imipenem, amikacin, and piperacillin/tazobactam. Meanwhile, the low susceptibilities of E. coli or Klebsiella spp. to amoxicillin/clavulanate, advanced-generation cephalosporins, and ciprofloxacin should be considered when determining empirical antibiotic therapy in clinical practice. PMID: 31808326 [PubMed - in process]
Source: Journal of Korean Medical Science - Category: Biomedical Science Tags: J Korean Med Sci Source Type: research
Publication date: Available online 6 December 2019Source: Food Research InternationalAuthor(s): Liping Guo, Yongcai Sun, Yinglian Zhu, Baowei Wang, Lin Xu, Ming Huang, Yufeng Li, Jingxin SunAbstractIn the present study, the action mechanism of ultrasound (US) combined with sodium hypochlorite (SH) against Escherichia coli was illustrated by different analysis, including reduction, particle size distribution, scanning electron microscopy (SEM), transmission electron microscopy (TEM), K+ leakage, confocal laser scanning microscopy (CLSM) and fluorescence spectroscopy of Escherichia coli. The results showed that ultrasound im...
Source: Food Research International - Category: Food Science Source Type: research
Publication date: 15 February 2020Source: Journal of Molecular Structure, Volume 1202Author(s): Satyendra Nath Shukla, Pratiksha Gaur, Mohan Lal Raidas, Bhaskar ChaurasiaAbstractTwo Schiff base ligands namely bis-2-((1E)-((Z)-2-(1,2-diphenylethylideneamino) phenylimino)methyl)phenol (L1) and bis-2-((1E)-((E)-2-(1-phenylethylideneamino)phenylimino) methyl)phenol (L2) were synthesized by tailored reaction of o-phenylenediamine with o-hydroxybenzaldehyde and 2-hydroxy-1,2-diphenylethanone/o-hydroxyacetophenone. The reaction of these ligands with Fe(III), Co(II), and Ni(II) salts yielded six complexes. Ligands and their metal ...
Source: Journal of Molecular Structure - Category: Molecular Biology Source Type: research
Publication date: Available online 6 December 2019Source: Catalysis TodayAuthor(s): Linghui Li, Yan Li, Yanzhang Li, Anhuai Lu, Hongrui Ding, Po Keung Wong, Hongli Sun, Junxian ShiAbstractTungstate oxide is a new kind of anionic semiconductor material, which has been received much attention due to its good photocatalytic performance and long-term stability. To facilitate large-scale application, the natural counterpart of tungstate oxide, wolframite, was firstly used as a visible-light mineral photocatalyst in this study. Its mineralogical and photocatalytic properties were characterized and compared with two synthetic end...
Source: Catalysis Today - Category: Chemistry Source Type: research
Publication date: Available online 6 December 2019Source: Journal of Photochemistry and Photobiology B: BiologyAuthor(s): Sai Kumar Tammina, Yang Wan, Yan Yan Li, Yaling YangAbstractA simple and one-step microwave digestion method was utilized to synthesize the highly photoluminescent glucosamine derived nitrogen and zinc doped carbon dots (N, Zn-CDs) with a bluish-green luminescence property. The synthesized N, Zn-CDs inherited a good photoluminescence property with a quantum yield of 74% and which were characterized with XPS, XRD, TEM, FT-IR, UV–Vis, and fluorescence spectrometry. More importantly N, Zn-CDs served ...
Source: Journal of Photochemistry and Photobiology B: Biology - Category: Speech-Language Pathology Source Type: research
Publication date: Available online 5 December 2019Source: Materials LettersAuthor(s): Sheena Raina, Anupma Thakur, Aditi Sharma, D. Pooja, Anu Priya MinhasAbstractThe present was the first report on the synthesis of Carbon dots (CDs) using the acetone leaf extract of Cannabis sativa, an abundant weed plant as a sole carbon precursor. The obtained ∼5 nm spherical CD particles (exhibiting 13% absolute quantum yield) were further to synthesize silver@CDs (Ag@CDs). CDs and Ag@CDs characterization revealed characteristic functional groups attributing to the aromatic, carboxylated and hydroxylated moieties. Ether and acetone...
Source: Materials Letters - Category: Materials Science Source Type: research
Foodborne Pathogens and Disease, Ahead of Print.
Source: Foodborne Pathogens and Disease - Category: Food Science Authors: Source Type: research
AbstractUpsurge of antibiotic resistance in wildlife poses unprecedented threat to wildlife conservation. Surveillance of antibiotic resistance at the human –wildlife interface is therefore needed. We evaluated differences in antibiotic resistance ofEscherichia coli isolates from human and the endangered black rhinoceros in Lambwe Valley, Kenya. We used standard microbiological techniques to carry out susceptibility assays using eight antibiotics of clinical and veterinary importance. Standard PCR method was used to characterize antibiotic resistance genes. There was no difference in resistance betweenE. coli isolate...
Source: EcoHealth - Category: Environmental Health Source Type: research
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