Structural-based Screening of L-phenylglycine Aminotransferase using L-phenylalanine as the Optimal Amino Donor: Recycling of L-phenylalanine to Produce L-phenylglycine

Shuang Ping Liu,Rui Xia Liu,Jian Mao,Liang Zhang,Zhongyang Ding,Zhenghua Gu,Gui-Yang Shi 한국생물공학회 2016 Biotechnology and Bioprocess Engineering Vol.21 No.1

The aproteinogenic amino acid, L-phenylglycine, is an important side chain building block for some drugs. It would be of great commercial and environmental value to biocatalyse L-phenylalanine to L-phenylglycine, and thus replace the organic synthesis method. To produce Lphenylglycine from L-phenylalanine, an L-phenylglycine aminotransferase was screened and characterized. HpgTAO showed high homology to α-aminoadipate aminotransferase. The L-phenylalanine binding site was near the residues S26, R401, N201, and G46 in HpgTAO, and L-phenylalanine formed a hydrogen bond with Asn20, which was similar to the substrate binding mechanism of α-aminoadipate aminotransferase. HpgTAO showed increased activity in alkalescent environment below 40°C. The kinetic analysis showed that L-phenylalanine had the highest affinity to HpgTAO, which ensured the recycle biosynthesis of Lphenylglycine from L-phenylalanine. To date, it was the only aminotransferase using L-phenylalanine as an optimal amino donor. The L-phenylglycine biocatalysis operon was also constructed by co-expressing the hmaS, hmo and hpgT by a single plasmid. The first in vitro conversion of Lphenylalanine to L-phenylglycine was achieved by directly using the L-phenylalanine fermentation broth as the raw material.

Single Phase Converter with Power Decoupling and Reactive Power Control for Bi-directional EV Charger

Peiji Zhu,Meiqin Mao,Shuang Xu 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

In traditional single phase converters for EV chargers used in private cars, the power flow is only unidirectional, and the bulky and short-lifetime electrolytic capacitors are usually used to issue the second-order ripple power between the AC and DC side. To address the problem, this paper proposes a control strategy to enable the single phase EV charger to achieve both four-quadrant operation and power decoupling control at the same time so that the EVs can respond dispatching commands from the future smart grid as distributed energy resources, meanwhile the size of the charger can be reduced. This control method is based on our previous work, proposed novel topology of single phase converter using a small film capacitor to decouple the second-order power. The operation principle of the proposed control strategy is analyzed in detail, and the design method of decoupling capacitance for both power decoupling and reactive power control purposes is provided. Simulation results by MATLAB/Simulink are provided to verify the effectiveness of the proposed control strategy.

IL-33 promotes IL-10 production in macrophages: a role for IL-33 in macrophage foam cell formation

Hai-Feng Zhang,Mao-Xiong Wu,Yong-Qing Lin,Shuang-Lun Xie,Tu-Cheng Huang,Pin-Ming Liu,Ru-Qiong Nie,Qin-Qi Meng,Nian-Sang Luo,Yang-Xin Chen,Jing-Feng Wang 생화학분자생물학회 2017 Experimental and molecular medicine Vol.49 No.-

We evaluated the role of IL-10- in IL-33-mediated cholesterol reduction in macrophage-derived foam cells (MFCs) and the mechanism by which IL-33 upregulates IL-10. Serum IL-33 and IL-10 levels in coronary artery disease patients were measured. The effects of IL-33 on intra-MFC cholesterol level, IL-10, ABCA1 and CD36 expression, ERK 1/2, Sp1, STAT3 and STAT4 activation, and IL-10 promoter activity were determined. Core sequences were identified using bioinformatic analysis and sitespecific mutagenesis. The serum IL-33 levels positively correlated with those of IL-10. IL-33 decreased cellular cholesterol level and upregulated IL-10 and ABCA1 but had no effect on CD36 expression. siRNA-IL-10 partially abolished cellular cholesterol reduction and ABCA1 elevation by IL-33 but did not reverse the decreased CD36 levels. IL-33 increased IL-10 mRNA production but had little effect on its stability. IL-33 induced ERK 1/2 phosphorylation and increased the luciferase expression driven by the IL-10 promoter, with the highest extent within the − 2000 to − 1752 bp segment of the 5′-flank of the transcription start site; these effects were counteracted by U0126. IL-33 activated Sp1, STAT3 and STAT4, but only the STAT3 binding site was predicted in the above segment. Site-directed mutagenesis of the predicted STAT3-binding sites (CTGCTTCCTGGCAGCAGAA→CTGCCTGGCAGCAGAA) reduced luciferase activity, and a STAT3 inhibitor blocked the regulatory effects of IL-33 on IL-10 expression. Chromatin immunoprecipitation (CHIP) confirmed the STAT3-binding sequences within the − 1997 to − 1700 and − 1091 to − 811 bp locus regions. IL-33 increased IL-10 expression in MFCs via activating ERK 1/2 and STAT3, which subsequently promoted IL-10 transcription and thus contributed to the beneficial effects of IL-33 on MFCs.

Clinical Significance of C-X-C Motif Chemokine Receptor 4 and Integrin αvβ6 Expression in Breast Cancer

Hongshan Huang,Mengci Yuan,Shuang-Ling Wu,Jinling Ba,Xinmiao Yu,Xiaoyun Mao,Feng Jin 한국유방암학회 2020 Journal of breast cancer Vol.23 No.2

Purpose: C-X-C motif chemokine receptor 4 (CXCR4) and integrin αvβ6 play important roles in the malignant progression of multiple cancers. However, it remains unclear whether the expression of one or both proteins in breast cancer (BC) is of clinical significance. In this study, we investigated the expression of CXCR4 and integrin αvβ6 in BC tissues and their correlation with clinicopathological characteristics, including survival. Methods: CXCR4 and αvβ6 expression in 111 BC tissues was examined by immunocytochemistry. Correlations between the expression of the 2 proteins and patient clinicopathological characteristic were investigated using the Kaplan–Meier method and the Cox proportional hazards model. Results: CXCR4 and αvβ6 were overexpressed in BC tissue compared with normal breast tissue. Overexpression of both molecules was related to lymph node status (p = 0.013 and p = 0.022, respectively). αvβ6 overexpression was also associated with tumor size (p = 0.044). A positive correlation was detected between the expression of CXCR4 and αvβ6 (r = 0.649, p = 0.001), and co-overexpression of both molecules was associated with tumor size (p = 0.018) and lymph node metastasis (p = 0.015). Kaplan–Meier analysis revealed that overexpression of CXCR4, αvβ6, or both molecules was associated with short overall survival (OS; p < 0.001, p < 0.001, and p = 0.009, respectively) and disease-free survival (DFS; p < 0.001, p = 0.005, and p = 0.019, respectively). Multivariate analysis indicated that lymph node metastasis was an independent prognostic factor for unfavorable OS and DFS (p = 0.002 and p = 0.005, respectively), whereas co-overexpression of CXCR4 and αvβ6 was an independent prognostic factor only for OS (p = 0.043). Conclusion: CXCR4 and αvβ6 may play synergistic roles in the progression of BC, and co-targeting of CXCR4 and αvβ6 could be a potential strategy for the prevention and treatment of BC

Application of Biodegradable Microcrystalline Cellulose to Improve the Crystallization Behavior of Isotactic Polybutene-1

Fu-hua Lin,Bo Wang,Shuang-dan Mao,Xiang-yang Li,Yu-ying Zhao,Ying-Hui Wei 한국고분자학회 2021 폴리머 Vol.45 No.5

The microcrystalline cellulose (MCC) was used for inducing crystallization of the isotactic polybutene-1 (iPB) and the maleic anhydride grafted polybutene-1 (MAPB) was used as a compatibilizer. The crystallization behavior of the composite demonstrated that the addition of MCC could significantly accelerate the crystallization rate of iPB and the addition of MAPB could improve the compatibility between MCC and iPB. Moreover, the properties of the composites with MAPB were better than those without MAPB. The crystal transformation had been completed after storage for 5 days and the form I was formed after storage for 3 days which was faster than pure iPB. The non-isothermal crystallization kinetics data of the composites indicated that the modified Avrami equation could describe the non-isothermal crystallization process of the iPB/MCC composite and the t1/2 of the composites was shortened for 24.32% and 40.27% which indicated that MCC could promote the crystallization of iPB.

A Novel EYA1 Mutation Causing Alternative RNA Splicing in a Chinese Family With Branchio-Oto Syndrome: Implications for Molecular Diagnosis and Clinical Application

Anhai Chen,Chufeng He,Yong Feng,Jie Ling,Xin Peng,Xianlin Liu,Shuang Mao,Yongjia Chen,Mengyao Qin,Shuai Zhang,Yijiang Bai,Jian Song,Zhili Feng,Lu Ma,Dinghua He,Lingyun Mei1 대한이비인후과학회 2023 Clinical and Experimental Otorhinolaryngology Vol.16 No.4

Objectives. Branchio-oto syndrome (BOS) primarily manifests as hearing loss, preauricular pits, and branchial defects. EYA1is the most common pathogenic gene, and splicing mutations account for a substantial proportion of cases. However,few studies have addressed the structural changes in the protein caused by splicing mutations and potential pathogenicfactors, and several studies have shown that middle-ear surgery has limited effectiveness in improving hearing in thesepatients. BOS has also been relatively infrequently reported in the Chinese population. This study explored the ge-netic etiology in the family of a proband with BOS and provided clinical treatment to improve the patient’s hearing. Methods. We collected detailed clinical features and peripheral blood samples from the patients and unaffected individualswithin the family. Pathogenic mutations were identified by whole-exome sequencing and cosegregation analysis andclassified according to the American College of Medical Genetics and Genomics guidelines. Alternative splicing wasverified through a minigene assay. The predicted three-dimensional protein structure and biochemical experimentswere used to investigate the pathogenicity of the mutation. The proband underwent middle-ear surgery and was fol-lowed up at 1 month and 6 months postoperatively to monitor auditory improvement. Results. A novel heterozygous EYA1 splicing variant (c.1050+4 A >C) was identified and classified as pathogenic (PVS1(RNA),PM2, PP1). Skipping of exon 11 of the EYA1 pre-mRNA was confirmed using a minigene assay. This mutation mayimpair EYA1-SIX1 interactions, as shown by an immunoprecipitation assay. The EYA1-Mut protein exhibited cellularmislocalization and decreased protein expression in cytological experiments. Middle-ear surgery significantly improvedhearing loss caused by bone-conduction abnormalities in the proband. Conclusion. We reported a novel splicing variant of EYA1 in a Chinese family with BOS and revealed the potential molec-ular pathogenic mechanism. The significant hearing improvement observed in the proband after middle-ear surgeryprovides a reference for auditory rehabilitation in similar patients.