BIOORGANIC CHEMISTRY
·
2023
·
IF 5.1
Yangyang Sun,Zhuzhu Tang,Yanjun Li,Yongkang Song,Hualei Wang,Dongzhi Wei,Shengli Yang
Hydration, a secondary activity mediated by nitrilase, is a promising new pathway for amide production. However, low hydration activity of nitrilase or trade-off between hydration and catalytic activity hinders its application in the production of amides. Here, natural C-terminal-truncated wild-type nitrilase, mined from a public database, obtained a high-hydration activity nitrilase as a novel evolutionary starting point for further protein engineering. The nitrilase Nit-74 from Spirosoma linguale DSM 74 was successfully obtained and exhibited the highest hydration activity level, performing 50.7 % nicotinamide formation and 87.6 % conversion to 2 mM substrate 3-cyanopyridine. Steric hindrance of the catalytic activity center and the N -terminus of the catalytic cysteine residue helped us identify three key residues: I166, W168, and T191. Saturation mutations resulted in three single mutants that further improved the hydration activity of N -heterocyclic nitriles. Among them, the mutant T191S performed 72.7 % nicotinamide formation, which was much higher than the previously reported highest level of 18.7 %. Additionally, mutants I166N and W168Y exhibited a 97.5 % 2-picolinamide ratio and 97.7 % isonicotinamide ratio without any loss of catalytic activity, which did not indicate a trade-off effect. Our results expand the screening and evolution library of promiscuous nitrilases with high hydration activity for amide formation.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2021
·
IF 4.098
Xueqing Guo,Yang Liu,Wenjuan Dong,Qin Hu,Yong Li,Shaomin Shuang,Chuan Dong,Lishuai Cai,Xiaojuan Gong
Azithromycin (AZM) 1 is one of the most widely used antibiotics. AZM abuse is easy to cause great harm to human body, so developing a rapid and sensitive method to detect AZM is of great importance. Herein, 3-aminothiophenol as only reaction precursor, nitrogen and sulfur co-doped carbon quantum dots (N,S-CQDs) 2 were fabricated by one-step hydrothermal carbonization method. All characteristics demonstrate that N,S-CQDs possess good water solubility, high fluorescence stability and low cytotoxicity. Without being disturbed by amino acids and drugs, the most interesting finding is that AZM can efficiently quench the fluorescence of N,S-CQDs by a synergistic effect of electrostatic interaction and static quenching. A fluorescent probe for the detection of AZM was constructed with high selectivity and good sensitivity, achieving two linear ranges of 2.5–32.3 μM and 37.2–110 μM and a limit of detection of 0.76 µM. The proposed fluorescent method was used for the detection of AZM in cells with fulfilling results. More importantly, the fluorescent probe was successfully used to the detection of AZM in tablets and human urine with recovery rate and relative standard deviations of 98.2–104.8% and 0.04–3.46%, respectively, which was confirmed by the standard method of HPLC-UV. This finding illustrates the usefulness and feasibility of N,S-CQDs as an effective fluorescent probe for the detection of AZM in tablets and human urine, which is helpful for supervising and guiding pharmacy.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Molecular Catalysis
·
2021
·
IF 5.062
Yu-Ting Shang,Jiufu Qin,Jin-Song Gong,Zi-Kai Wang,Heng Li,Hui Li,Jin-Song Shi,Zheng-Hong Xu
A nicotinate dehydrogenase producing strain was isolated and identified to be Pseudomonas putida , which could bio-transform nicotinic acid into 6-hydroxynicotinic acid. The activity of nicotinate dehydrogenase towards nicotinic acid could reach up to 1.11 U/mL and the yield of 6-hydroxynicotinic acid accumulated to 176 g/L within 30 h with a space time yield of 1.36 g/(g•h). In order to further improve its catalytic potential, a mutant library was constructed through atmospheric and room temperature plasma (ARTP) and rapidly screened by a high-throughput screening strategy, which obtained a mutant strain mut-5 with activity of 2.68 U/mL. Via developing a nitrilase-nicotinate dehydrogenase enzymatic cascade system, 54.5 g/L 6-hydroxynicotinic acid could be obtained within 585 min with 3-cyanopyridine as the substrate, which would further reduce the production costs. The results indicated that the nicotinate dehydrogenase (separately or combining with nitrilase) could serve as a superior catalyst for 6-hydroxynicotinic acid production. To our knowledge, the nicotinate dehydrogenase activity reported in this study was the highest level in literature to date.
✓ 已验证
产品关联
DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2020
·
IF 6.551
Naiyi Yin,Zeliang Han,Huili Du,Pengfei Wang,Yunpeng Li,Xiaochen Chen,Guoxin Sun,Yanshan Cui,Zhengyi Hu
To determine the effect of vitamin supplements on the oral bioaccessibility of Pb in soils, Pb bioaccessibility was measured in the presence of 9 vitamins by a physiologically based extraction test. Gastric Pb bioaccessibility (G-BA, 2.6–83.3%) was found to be mostly reduced (1.1–3.1 fold) in the presence of B vitamins, specifically vitamins B1, B6, and B9. In contrast, a significant increase in Pb G-BA was observed with vitamin C and E involved. In the small intestinal phases, Pb bioaccessibility (I-BA) ranged from 0.1% to 16.0%, being 5–50 fold lower than the corresponding G-BA values. Vitamin C supplementation showed a 7-fold increase in Pb I-BA, with a similar increase presented in approximately 30% of samples treated to vitamin B involvement. Lead liberation in gastrointestinal digests was associated with the dissolution of Fe and Mn regulated by vitamins. In conclusion, the addition of B vitamins resulted in the reduction of gastric Pb bioaccessibility, but the bioaccessibility value increased in participation of vitamin C and E. Elevated intestinal bioaccessibility was found especially for vitamin C. This should contribute to more accurate assessment of health risks from contaminated soils. Nutritional management aimed at preventing Pb-induced toxicity can benefit from knowledge of vitamin influence on soil Pb bioaccessibility.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2020
·
IF 3.232
Lan-Fang Pang,Hao Wu,Meng-Xia Wei,Xiao-Feng Guo,Hong Wang
The spores of Bacillus anthracis are highly deadly to human beings and animals, and are concurrently potential biological warfare agents. Hence, the rapid and sensitive monitoring Bacillus anthracis biomarker, dipicolinic acid (DPA), is very desirable. Herein, orange/green dual-emissive carbon dots (OG-CDs) were synthesized via the hydrothermal approach. The OG-CDs not only emitted dual fluorescence at 527 and 590 nm under the single 503 nm excitation, but also exhibited excellent water solubility, good photostability and great salt tolerance. The fluorescence of the OG-CDs at 527 nm can be completely quenched when chelated with Cu(II). However, because of the stronger chelation between DPA and Cu(II), the fluorescence restored rapidly on subsequent addition of DPA. As such, the CD-Cu(II) system can be used for determination of DPA based on the fluorescence “off-on” response. Under optimum conditions, the detection limit for DPA was 56 nM, with a linear range of 0.5–12.5 μM. The established CD-Cu(II) based spectrofluorometric method has been applied to the analysis of DPA in real water samples with recoveries of 93.6%–104.3%. More remarkably, the CD-Cu(II) probe also has been successfully applied for the imaging of DPA in Escherichia coli with excellent bio-compatibility.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Applied Bio Materials
·
2020
·
IF 0
Zhong-Xia Wang,Lei Hu,Yuan-Fei Gao,Fen-Ying Kong,Heng-Ye Li,Jing Zhu,Hai-Lin Fang,Wei Wang
The development of near-infrared (NIR) emission nanoprobes for the ratiometric fluorescent determination of living cells in vitro/vivo is of great analytical importance. In this work, dual-NIR-emissive Zn-doped carbon-based nanosheets (Zn-CNSHs) were prepared with a beneficial and special donor−π–acceptor-conjugated (D−π–A-conjugated) spatial framework, which resulted in not only a much lower HOMO–LUMO energy level but also excellent biocompatibility and physicochemical properties. The Zn-CNSHs were prepared by simple one-pot solvothermal synthesis with zinc gluconate (ZGN) and a strong acid and exhibited two distinctive photoluminescence (PL) peaks at 620 and 720 nm with the 600 nm excitation. The 620 nm peak intensity was dependent on dipicolinic acid (DPA) owing to the aggregation-induced emission enhancement effect via the strong intersheet hydrogen bonds between Zn-CNSHs and DPA, enabling the ratiometric fluorescent determination of DPA, an important clinical anthrax biomarker. An excellent calibration curve showed linear regions over the range of 0.05–500 μM between the ratio of PL intensity (PL620 nm/PL720 nm) and the concentrations of DPA. The detection limit was down to 21.7 nM. Based on the high stability, low cytotoxicity, high selectivity, and outstanding PL-reliant sensitivity for the DPA assay, the nanoprobe has been successfully used to monitor DPA in serum, wastewater, and cells.
✓ 已验证
产品关联
DOI
PubMed
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2020
·
IF 3.232
Shasha Feng,Fubin Pei,Yi Wu,Jingjing Lv,Qingli Hao,Tinghai Yang,Zhaoyang Tong,Wu Lei
A novel ratiometric fluorescent sensor based on Förster resonance energy transfer (FRET) platform was designed for riboflavin (RF) detection. The graphitic carbon nitrides quantum dots - Zn-MOF composite (g-CNQDs@Zn-MOF) was used as the fluorescent probe . In the FRET system, g-CNQDs@Zn-MOF and RF acted as donor and acceptor, respectively. The probe exhibited high sensitivity and good selectivity to RF, and had been successfully used for the detection of RF in milk and vitamin B 2 tablets. The detection limit of the sensor was 15 nM. The strategy expanded the application of MOF in sensing filed and provided a new method for the detection of RF.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MICROCHEMICAL JOURNAL
·
2020
·
IF 3.594
Ru-Ru Gao,Wei Dong
A new strategy was put forward to fabricate amorphous coordination polymer nanoparticles (CPNs) self-assembled by lanthanide ions (Ln 3+ ) and ATP whose adenine subunit and phosphate group served as bidentate ligands for Ln 3+ . These ATP/Ln 3+ CPNs showed weak luminescence but could be sensitized by introduction of external stimuli. Hence, they could be “artificial tongues” to respond to multifarious analytes (pyridine carboxylic acids or metal ions). Inspired the fact that both ATP/Tb 3+ and ATP/Eu 3+ CPNs presented ultrasensitive responses to 2, 6-pyridinedicarboxylic acid, a tunable chromaticity of emission from red to green was achieved by simply varying the doping ratio of Tb 3+ and Eu 3+ into ATP. Moreover, the ATP/Ln 3+ CPNs exhibited surprisingly encapsulation properties for guest dye, indicating the feature of self-adaptive assembly. These features above provided the possibility of performing logic operations. By employing these CPNs as logic operators, the implementation of Boolean logic gates (INH and AND) and integrative logic operation (INH-INH) connecting the elementary logic operations has been successfully achieved.
✓ 已验证
产品关联
DOI
高影响因子
TALANTA
·
2020
·
IF 5.339
Xinrong Jiang,Xiaoming Chen,Tao Wang,Yuexin Li,Aiwu Pan,Jianmin Wu
Metabolites in the body fluid are becoming a rich source of disease biomarkers. Developing an effective and high throughput detection and analysis platform of metabolites is of great importance for potential biomarker discovery and validation. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) has been successfully applied in rapid biomolecules detection in large scale. However, non-negligible background interference in low molecule-weight region still constitutes a main challenge even though various nanomaterials have been developed as an alternative to traditional organic matrix. In this work, a novel composite chip, silicon nanowires loaded with fluorinated ethylene propylene (FEP@SiNWs) was fabricated. It can serve as an excellent substrate for nanostructure-initiator mass spectrometry (NIMS) detection with ultra-low background noise in low molecular weight region (<500 Da). Ion desorption efficiency and internal energy transfer of FEP@SiNWs were studied using benzylpyridinium salt and tetraphenylboron salt as thermometer chemicals. The results indicated that a non-thermal desorption mechanism might be involved in the LDI process on FEP@SiNWs. Owing to the higher LDI efficiency and low background interference of this novel substrate, the metabolic fingerprint of complex bio-fluids, such as human saliva, can be sensitively and stably acquired. As a proof of concept, FEP@SiNWs chip was successfully used in the detection of salivary metabolites. With the assistance of multivariate analysis, 22 metabolic candidates (p < 0.05) which can discriminate type 2 diabetes mellitus (2-DM) and healthy volunteers were found and identified. The role of these feature metabolites in the metabolic pathway involved in 2-DM was confirmed by literature mining. This work demonstrates that FEP@SiNWs-based NIMS might be served as an efficient and high throughput platform for metabolic biomarker exploration and clinical diagnosis.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
TALANTA
·
2020
·
IF 5.339
Feiyao He,Jinwei Yin,Tianzhi Wang,Juan Pu,Jianxiong Dai,Zhongjun Zhao,Yixiang Duan
A new ambient ionization technique named laser ablation micro-fabricated glow discharge plasma (LA-MFGDP) was developed for mass spectrometry in this study. This technique used low energy laser for sample ablation and ionized sample aerosol with MFGDP in sequence. The combination of laser ablation and MFGDP exhibited a synergetic effect that significantly improved the performance of MFGDP. Experimental results showed that MFGDP dominated the ionization process while laser played the role of desorption in LA-MFGDP. [M+H] + and M + proved that proton transfer reactions and charge transfer reactions were involved in the ionization process, respectively, indicating that the ionization character was the same as MFGDP. LA-MFGDP could analyze less volatile samples that were unable to be detected by MFGDP because laser significantly improved the ionization capability of MFGDP. Strong ion signals were obtained by LA-MFGDP with low sample consumption. The limits of detection (LODs) of LA-MFGDP was as low as three orders of magnitude than that of MFGDP, which demonstrated that LA-MFGDP possessed an outstanding advantage in detecting trace substances. LA-MFGDP was successfully applied to detect pharmaceutical tablets without any pretreatment. Benefited from the excellent performance, LA-MFGDP offers great potential in broadening the application of ambient mass spectrometry.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
TALANTA
·
2020
·
IF 5.339
Jing Wang,Daquan Li,Yu Qiu,Xinyue Liu,Liang Huang,Huimin Wen,Jun Hu
We reported Eu(III) functionalized carbon dots (CDs-Eu) as a novel ratiometric fluorescent probe for point-of-care testing (POCT) of dipicolinic acid (DPA), a biomarker of anthrax. The probe was synthesized simply by coordination interaction between Eu(III) ions and the CDs with carboxyl and amino groups. Upon addition of DPA, the intrinsic red luminescence of Eu(III) ions can be sensitized due to the presence of energy transfer when DPA chromophore coordinated with Eu(III) ions. The fluorescence peaking at 530 nm as a reference remained essentially constant, leading to ratiometric fluorescence response toward DPA. This approach exhibited a linearity range from 0.5 nM to 5 μM and a detection limit of 0.8 nM. More Importantly, the combination of probe-based test paper and smartphone provided a convenient approach for visual POCT of DPA with a detection limit of 67 nM, which was lower than other reported test paper for DPA detection. The color of fluorescence gradually changed from green to red as the DPA increases, which can be captured by a smartphone and further quantitatively analyzed with a built-in Color Analyzer App. The satisfactory result of detecting DPA accurately and reliably in real samples by the test paper certified its practicality in POCT of DPA.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ANALYTICAL CHEMISTRY
·
2020
·
IF 6.785
Huifang Wu,Changlun Tong
Nitrite (NO2–) and mercury (Hg2+) ions are recognized as two typical inorganic contaminations that can cause severe damage to the environment and humans. In this paper, the energy transfer from carbon quantum dots (CQDs) to Tb3+ by the antenna effect was found, which can promote the f–f transition of Tb3+ and emit strong characteristic fluorescence of Tb3+. Based on CQD-Tb3+ and 3-aminophenylboronic acid (APBA), which have respectively sensitive and specific fluorescent response to NO2– and Hg2+ with different fluorescent signals, a dual-emission fluorescent probe of the CQD-Tb3+/APBA hybrid was thus fabricated for the simultaneous detection of NO2– and Hg2+ in environmental water samples. They emit dual-emission fluorescence peaks centered at 373 and 545 nm, respectively. A good linearity between the quenching efficiency of (F0 – F)/F0 and the concentrations of NO2– and Hg2+ was in the range of 5.0–1200.0 nM for NO2– and 0.1–6.0 μM for Hg2+. The limit of detection (LOD, 3σ/K) is ultrasensitive for NO2– (2.0 nM), and the LOD for Hg2+ is 38.1 nM. The dual-emission fluorescent probe was successfully applied for the determination of NO2– and Hg2+ in various environmental water samples. The possible luminescence and fluorescence quenching mechanisms of the probe are also discussed in detail. This study provides a new approach for fabricating a multifunctional fluorescent probe or sensor and a prospective application in environmental monitoring.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）