INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2022
·
IF 8.025
Zi-Fu Ni,Na Li,Pei Xu,Ze-Wang Guo,Min-Hua Zong,Wen-Yong Lou
Ammonia lyases have great application potential in food and pharmaceuticals owing to their unique ammonia addition reaction and atom economy. A novel methylaspartate ammonia-lyase, Ec MAL, from E. coli O157:H7 showed high catalytic activity. To further strengthen its thermostability and activity, disulfide bond and backbone cyclization (cyclase) variants were constructed by rational design, respectively. Among them, variant M3, with a disulfide bond introduced, exhibited a 2.3-fold increase in half-life at 50 °C, while cyclase variant M8 showed better performance, with 25.9-fold increases. The synergistic promotion effect of this combinational strategy on activity and stability was also investigated, and the combined mutant M9 exhibited a 1.1-fold improvement in catalytic efficiency while maintaining good thermostability. Circular dichroism analysis and molecular dynamics simulation confirmed that the main sources of improved thermostability were reduced atomic fluctuation and a more stable secondary structure. To our knowledge, this is the first example of combining the introduction of disulfide bonds with cyclase construction to improve enzyme stability, which was characterized by modification away from the enzyme active center, and provided a new method for adjusting enzyme thermostability.
研究领域:
生物化学
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蛋白质工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2018
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IF 4.61
Mengqi Zheng,Yuxing Han,Chunyan Xu,Hongjun Han,Zhengwen Zhang
This paper originally investigated toxicity discrimination of typical cyclic compounds and bioassays selection on toxicity evaluation for coal gasification wastewater (CGW) effluent with mechanism-oriented investigation. Initially, representative cyclic toxicants were selected and classified with quantitative structure–toxicity relationship (QSTR). Nitrogen heterocyclic compounds (NHCs) and polycyclic aromatic hydrocarbons (PAHs) were basically discriminated as nonpolar narcotics with significant correlation to hydrophobicity ( p < 0.05, R 2 = 0.8668–0.9635), while phenols were regarded as polar narcotics and reactive compounds due to slight correlation to hydrophobicity ( p > 0.05, R 2 < 0.5). Furthermore, specific mechanism of actions (MOAs) to various organisms revealed that phenols were discriminated as critical source of acute toxicity in CGW, with short-term visible and irreversible damage. However, NHCs and PAHs, which exerted accumulation toxicity rather than acute toxicity, might result in potential mutagenicity and unpredictable risk along the food chain. Afterwards, based on species sensitivity to typical toxicants and application in real CGW effluent, non-applicability of Chlorella vulgaris ( C. vulgaris ) was validated in toxicity evaluation. While Daphnia magna ( D. magna ) was suggested as a toxicity bioassay in entire effluent due to the highest sensitivity and applicability. Tetrahymena thermophile ( T. pyriformis ) might be applicable in effluent with low biodegradability due to similar evaluation results (TU = 8.90) to D. magna (TU = 6.67) in aerobic effluent. Finally, the relationship between toxicity and bioavailability based on typical pollutants and model species illustrated necessity for dualism toxicity-biodegradability investigation on CGW.
研究领域:
环境科学
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毒理学
✓ 已验证
DOI
高影响因子
ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE
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2022
·Vol. 649
·期 4
·e202200279
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IF 1.414
Shuai-Cong Huo,Yao Li,Peng-Fei Ji,De-Xiang Zhang,Zhi-Jiao Zhang,Ying Yang,Herbert W. Roesky
Treatments of β -diketiminate aluminum dihydride LAlH 2 (L=HC[C(Me)N(Ar)] 2 , Ar=2,6- i Pr 2 C 6 H 3 ) with (2-chlorophenyl)methanol, 2,3-dimethylbutane-2,3-diol, 2,2-dimethylpropane-1,3-diol, 2,2-bis(bromomethyl)propane-1,3-diol, and p -diphenol resulted in the formation of compounds containing the C−O−Al−O−C linkages, including the acyclic LAl[( μ -O)CH 2 ( o -Cl−C 6 H 4 ) 2 ] 2 ( 1 ), the five-membered ring LAl[( μ -O)CMe 2 ] 2 ( 2 ), the six-membered ring LAl[( μ -O)CH 2 ] 2 CMe 2 ( 3 ) and LAl[( μ -O)CH 2 ] 2 C(CH 2 Br) 2 ( 4 ), and the macrocyclic [LAl( μ -O) 2 ( p -C 6 H 4 )] 4 ( 5 ), respectively. These practices prove that β -diketiminate aluminum dihydride is a valuable precursor for the preparation of acyclic and cyclic systems. 1 – 5 were characterized by melting point, 1 H and 13 C NMR, FT-IR, and single-crystal X-ray diffraction studies.
研究领域:
无机化学
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材料化学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2021
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IF 13.273
Lujia Ding,Pengcheng Wang,Qiuhan Lin,Dongxue Li,Yuangang Xu,Ming Lu
Fused cyclic energetic compounds are a unique class of large conjugated structures containing two or more rings, and have been identified as promising competitors for traditional energetic materials. In the present work, we investigated 5-amino-6-oxo-4,6-dihydro-[1,2,5]oxadiazolo[3′,4′:5,6]pyrido[4,3- d ][1,2,3]triazine 8-oxide ( 3 ) in detail as a fused amphoteric energetic molecule that can be protonated and deprotonated by acids and bases to obtain its cationic ( 11 – 13 ) and anionic ( 4 – 10 ) salts. All the new compounds were thoroughly characterized by infrared and multinuclear NMR ( 1 H and 13 C) spectroscopy, and elemental analysis. The structural features of 3 – 6 , 9 , 10 , 12 , and 13 were investigated by single-crystal X-ray diffractions and different theoretical techniques (Hirshfeld surfaces analyses, and noncovalent interactions). The aromaticity of compound 3 was studied via localized orbital locator- π and iso -chemical shielding surfaces (ICSS). Their thermal decomposition temperatures were investigated by differential scanning calorimetry and thermogravimetry to be 310–344 °C (onset). In addition, impact and friction tests revealed that these compounds were insensitive. Densities, heats of formation and detonation properties were measured by a gas pycnometer, calculated using the Born-Haber energy cycle and EXPLO5 v6.05.04 program, respectively. The neutral compound 3 and all its non-metallic salts have better detonation properties than HNS and PYX and lower sensitivities. In particular, salt 11 (N + O: 61.74 %, T d : 330 °C, Δ H f : 1.68 kJ g −1 , D : 8.795 km s −1 , P : 36.0 GPa, IS: > 40 J, FS: > 360 N) is a potential candidate for heat-resistant explosives.
研究领域:
化学
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材料科学
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爆炸物研究
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2025
·
IF 21.1
Xuepeng Wang,Wei Deng,Yimin Xiong,Syed Shatir A. Syed-Hassan,Qian Liu,Xun Hu,Jun Xu,Song Hu,Yi Wang,Jun Xiang
Bio-oil, a carbon-rich liquid from the pyrolysis of renewable biomass, holds potential as a petroleum substitute that can be upgraded to bio-fuels and high-value chemicals. Electrochemical upgrading offers milder conditions, avoiding the harsh requirements and catalyst deactivation of thermochemical upgrading. However, most organics in bio-oil have hydrogenation potentials above hydrogen evolution potentials, generally resulting in severe hydrogen evolution and low Faradaic efficiency. Here, we report an efficient and mild electrochemical system for the direct upgrading of real water-soluble bio-oil. By leveraging hydrogen-transfer catalysis and synergistic catalysis of multimetallic nanocatalysts, we enhance hydrogenation while suppressing hydrogen evolution, achieving bio-oil-to-bio-fuel conversion under ambient conditions. Major water-soluble bio-oil components show > 99 % conversion at 100–500 mA cm⁻², yielding saturated cyclic compounds (e.g., cyclohexane, cyclohexanol, cyclopentanol). Notably, this process achieved a Faradaic efficiency of 74.12 % within the first 30 min at 100 mA cm⁻². Combined theoretical and experimental analyses reveal competitive hydrogenation behaviors among water-soluble bio-oil components and elucidate the underlying cooperative catalytic mechanisms on the multimetallic surfaces. This work represents an important step toward the mild, efficient, and practical upgrading of real bio-oil.
研究领域:
可再生能源
·
电催化
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可持续化学
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生物燃料
·
纳米材料
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）