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Zhong Y, Li Y, Chen Q, Ji S, Xu M, Liu Y, Wu X, Li S, Li K, Lu B. Catalytic efficiency and thermal stability promotion of the cassava linamarase with multiple mutations for better cyanogenic glycoside degradation. Int J Biol Macromol 2023; 253:126677. [PMID: 37717874 DOI: 10.1016/j.ijbiomac.2023.126677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 08/22/2023] [Accepted: 09/01/2023] [Indexed: 09/19/2023]
Abstract
In our previous study, we found that cassava cyanogenic glycosides had an acute health risk. Therefore, to solve this problem, the improvement of specific degradation of cyanogenic glycosides of cassava linamarase during processing is the key. In this study, the catalytic activity and thermal stability of enzymes were screened before investigating the degradation efficiency of cyanogenic glycosides with a cassava linamarase mutant K263P-T53F-S366R-V335C-F339C (CASmut) -controlled technique. The CASmut was obtained with the optimum temperature of 45 °C, which was improved by 10 °C. The specific activity of CASmut was 85.1 ± 4.6 U/mg, which was 2.02 times higher than that of the wild type. Molecular dynamics simulation analysis and flexible docking showed there were more hydrogen bonding interactions at the pocket, and the aliphatic glycoside of the linamarin was partially surrounded by hydrophobic residues. The optimum conditions of degradation reactions was screened with CASmut addition of 47 mg/L at 45 °C, pH 6.0. The CASmut combined with ultrasonication improved the degradation from 478.2 ± 10.4 mg/kg to 86.7 ± 7.4 mg/kg. Those results indicating the great potential of CASmut in applying in the cassava food or cyanogenic food. However, challenges in terms of the catalytic mechanism research is worthy of being noticed in further studies.
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Affiliation(s)
- Yongheng Zhong
- College of Biosystems Engineering and Food Science, Key Laboratory for Quality Evaluation and Health Benefit of Agro-Products of Ministry of Agriculture and Rural Affairs, Key Laboratory for Quality and Safety Risk Assessment of Agro-Products Storage and Preservation of Ministry of Agriculture and Rural Affairs, Zhejiang University, Hangzhou 310058, China
| | - Ye Li
- College of Biosystems Engineering and Food Science, Key Laboratory for Quality Evaluation and Health Benefit of Agro-Products of Ministry of Agriculture and Rural Affairs, Key Laboratory for Quality and Safety Risk Assessment of Agro-Products Storage and Preservation of Ministry of Agriculture and Rural Affairs, Zhejiang University, Hangzhou 310058, China
| | - Qi Chen
- College of Biosystems Engineering and Food Science, Key Laboratory for Quality Evaluation and Health Benefit of Agro-Products of Ministry of Agriculture and Rural Affairs, Key Laboratory for Quality and Safety Risk Assessment of Agro-Products Storage and Preservation of Ministry of Agriculture and Rural Affairs, Zhejiang University, Hangzhou 310058, China
| | - Shengyang Ji
- College of Biosystems Engineering and Food Science, Key Laboratory for Quality Evaluation and Health Benefit of Agro-Products of Ministry of Agriculture and Rural Affairs, Key Laboratory for Quality and Safety Risk Assessment of Agro-Products Storage and Preservation of Ministry of Agriculture and Rural Affairs, Zhejiang University, Hangzhou 310058, China
| | - Minhao Xu
- College of Biosystems Engineering and Food Science, Key Laboratory for Quality Evaluation and Health Benefit of Agro-Products of Ministry of Agriculture and Rural Affairs, Key Laboratory for Quality and Safety Risk Assessment of Agro-Products Storage and Preservation of Ministry of Agriculture and Rural Affairs, Zhejiang University, Hangzhou 310058, China
| | - Yuqi Liu
- College of Biosystems Engineering and Food Science, Key Laboratory for Quality Evaluation and Health Benefit of Agro-Products of Ministry of Agriculture and Rural Affairs, Key Laboratory for Quality and Safety Risk Assessment of Agro-Products Storage and Preservation of Ministry of Agriculture and Rural Affairs, Zhejiang University, Hangzhou 310058, China
| | - Xiaodan Wu
- Analysis Center of Agrobiology and Environmental Sciences, Zhejiang University, Hangzhou 310058, China
| | - Shimin Li
- Analysis Center of Agrobiology and Environmental Sciences, Zhejiang University, Hangzhou 310058, China
| | - Kaimian Li
- Tropical Crop Germplasm Research Institute, Chinese Academy of Tropical Agricultural Sciences, Danzhou 571737, China
| | - Baiyi Lu
- College of Biosystems Engineering and Food Science, Key Laboratory for Quality Evaluation and Health Benefit of Agro-Products of Ministry of Agriculture and Rural Affairs, Key Laboratory for Quality and Safety Risk Assessment of Agro-Products Storage and Preservation of Ministry of Agriculture and Rural Affairs, Zhejiang University, Hangzhou 310058, China.
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Characterization of a New Glucose-Tolerant GH1 β-Glycosidase from Aspergillus fumigatus with Transglycosylation Activity. Int J Mol Sci 2023; 24:ijms24054489. [PMID: 36901919 PMCID: PMC10003650 DOI: 10.3390/ijms24054489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 02/17/2023] [Accepted: 02/20/2023] [Indexed: 03/02/2023] Open
Abstract
Concern over environmental impacts has spurred many efforts to replace fossil fuels with biofuels such as ethanol. However, for this to be possible, it is necessary to invest in other production technologies, such as second generation (2G) ethanol, in order to raise the levels of this product and meet the growing demand. Currently, this type of production is not yet economically feasible, due to the high costs of the enzyme cocktails used in saccharification stage of lignocellulosic biomass. In order to optimize these cocktails, the search for enzymes with superior activities has been the goal of several research groups. For this end, we have characterized the new β-glycosidase AfBgl1.3 from A. fumigatus after expression and purification in Pichia pastoris X-33. Structural analysis by circular dichroism revealed that increasing temperature destructured the enzyme; the apparent Tm value was 48.5 °C. The percentages of α-helix (36.3%) and β-sheet (12.4%) secondary structures at 25 °C were predicted. Biochemical characterization suggested that the optimal conditions for AfBgl1.3 were pH 6.0 and temperature of 40 °C. At 30 and 40 °C, the enzyme was stable and retained about 90% and 50% of its activity, respectively, after pre-incubation for 24 h. In addition, the enzyme was highly stable at pH between 5 and 8, retaining over 65% of its activity after pre-incubation for 48 h. AfBgl1.3 co-stimulation with 50-250 mM glucose enhanced its specific activity by 1.4-fold and revealed its high tolerance to glucose (IC50 = 2042 mM). The enzyme was active toward the substrates salicin (495.0 ± 49.0 U mg-1), pNPG (340.5 ± 18.6 U mg-1), cellobiose (89.3 ± 5.1 U mg-1), and lactose (45.1 ± 0.5 U mg-1), so it had broad specificity. The Vmax values were 656.0 ± 17.5, 706.5 ± 23.8, and 132.6 ± 7.1 U mg-1 toward p-nitrophenyl-β-D-glucopyranoside (pNPG), D-(-)-salicin, and cellobiose, respectively. AfBgl1.3 displayed transglycosylation activity, forming cellotriose from cellobiose. The addition of AfBgl1.3 as a supplement at 0.9 FPU/g of cocktail Celluclast® 1.5L increased carboxymethyl cellulose (CMC) conversion to reducing sugars (g L-1) by about 26% after 12 h. Moreover, AfBgl1.3 acted synergistically with other Aspergillus fumigatus cellulases already characterized by our research group-CMC and sugarcane delignified bagasse were degraded, releasing more reducing sugars compared to the control. These results are important in the search for new cellulases and in the optimization of enzyme cocktails for saccharification.
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Zuo Y, Li B, Guan S, Jia J, Xu X, Zhang Z, Lu Z, Li X, Pang X. EuRBG10 involved in indole alkaloids biosynthesis in Eucommia ulmoides induced by drought and salt stresses. JOURNAL OF PLANT PHYSIOLOGY 2022; 278:153813. [PMID: 36179396 DOI: 10.1016/j.jplph.2022.153813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 09/02/2022] [Accepted: 09/10/2022] [Indexed: 06/16/2023]
Abstract
Alkaloids are natural products with many important medicinal activities. To explore the mechanism of abiotic stress promoting alkaloid biosynthesis in Eucommia ulmoides, transcriptomic analysis and metabonomic analysis were used, virus-induced gene silencing (VIGS) lines of target gene were constructed. The results showed that drought and salt stress caused wilting and blackening of leaves, decreased chlorophyll level, and significantly induced MDA and relative conductivity. To resist the damage of stress to cells, the level of secondary metabolites such as alkaloids increased significantly with the extension of stress time. Transcriptomic results showed that, were. Six alkaloid related genes (AWGs) were gathered in five modules positively correlated with either salt stress or alkaloid contents by WGCNA. Results of GO and KEGG enrichment revealed that biosynthesis of alkaloid, especially indole alkaloid was induced, and degradation of alkaloid was inhibited under salt stress. Combining the results of transcriptome and metabolomics, it was suggested that EuRBG10 promotes the production of indole alkaloids and EuAMO5 inhibits the degradation of alkaloids, which may be the core mechanism of the indole alkaloid biosynthesis pathway (map00901) induced by salt stress. The results of these hub proteins were also consistent with the chordal graph of KEGG enrichment. Hub roles of EuRGB10 was checked in E. ulmoides by VIGS. Our findings provide a preliminary understanding of abiotic stress regulating secondary metabolites such as alkaloids, and propose hub genes that can be used to improve the level of bioactive components in medicinal plant.
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Affiliation(s)
- Yanjun Zuo
- College of Medical Technology and Engineering, Henan University of Science and Technology, Luoyang, 471023, China
| | - Bairu Li
- College of Food and Bioengineering, Henan University of Science and Technology, Luoyang, 471023, China
| | - Suixia Guan
- College of Food and Bioengineering, Henan University of Science and Technology, Luoyang, 471023, China
| | - Jingyu Jia
- College of Food and Bioengineering, Henan University of Science and Technology, Luoyang, 471023, China
| | - Xinjie Xu
- College of Food and Bioengineering, Henan University of Science and Technology, Luoyang, 471023, China
| | - Zilong Zhang
- College of Food and Bioengineering, Henan University of Science and Technology, Luoyang, 471023, China
| | - Zheng Lu
- Department of Biology, Institute of Marine Sciences, Shantou University, Shantou, 515063, China
| | - Xin Li
- College of Food and Bioengineering, Henan University of Science and Technology, Luoyang, 471023, China; National Demonstration Center for Experimental Food Processing and Safety Education, Luoyang, 471000, China; Henan Engineering Research Center of Food Microbiology, Luoyang, 471023, China.
| | - Xinyue Pang
- College of Medical Technology and Engineering, Henan University of Science and Technology, Luoyang, 471023, China.
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