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Molecular characterization and structure basis of a malonyltransferase with both substrate promiscuity and catalytic regiospecificity from Cistanche tubulosa

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Acta Pharmaceutica Sinica B 2024年第5期14卷 2333-2348页

作者： liu X. Liu Y. Xu X. Huang W. yan y. Wang y. Tian W. Mo T. Cui X. Li J. Shi S.-P. Tu P. Modern Research Center for Traditional Chinese Medicine Beijing Research Institute of Chinese Medicine Beijing University of Chinese Medicine Beijing 100029 China Modern Research Center for Traditional Chinese Medicine School of Chinese Materia Medica Beijing University of Chinese Medicine Beijing 100029 China

Enzymatic malonylation of natural glycosides provides a promising alternative method for drug-like malonylated glycosides supply. However, the catalytic potential and structural basis of plant malonyltransferase are far from being fully elucidated. This work identified a new malonyltransferase CtMaT1 from Cistanche tubulosa. It displayed unprecedented mono- and/or di-malonylation activity toward diverse glucosides with different aglycons. A “one-pot” system by CtMaT1 and a malonyl-CoA synthetase was established to biosynthesize nine new malonylated glucosides. Structural investigations revealed that CtMaT1 possesses an adequately spacious acyl-acceptor pocket capable of accommodating diverse glucosides. Additionally, it recognizes malonyl-CoA through strong electrotactic and hydrogen interactions. QM/MM calculation revealed the H167-mediated SN2 reaction mechanism of CtMaT1, while dynamic simulations detected the formation of stable hydrogen bonds between the glucose-6-OH group and H167, resulting in its high malonylation regiospecificity. Calculated energy profiles of two isomeric glycosides highlighted lower reaction energy barriers towards glucoside substrates, emphasizing CtMaT1's preference for glucosides. Furthermore, a mutant CtMaT1H36A with notably increased di-malonylation activity was obtained. The underlying molecular mechanism was illuminated through MM/GBSA binding free energy calculation. This study significantly advances the understanding of plant acyltransferases from both functional and protein structural perspectives, while also providing a versatile tool for enzymatic malonylation applications in pharmacology. © 2024 The Authors

关键词： Enzymatic catalysis Enzyme promiscuity Malonylated glycosides Malonyltransferase Plant acyltransferase

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Extracellular vesicles:Emerging tools as therapeutic agent carriers

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Acta Pharmaceutica Sinica B 2022年第10期12卷 3822-3842页

作者： Shan liu Xue Wu Sutapa Chandra Christopher Lyon Bo Ning Li jiang Jia Fan Tony y.Hu Sichuan Provincial Key Laboratory for Human Disease Gene Study Department of Medical GeneticsDepartment of Laboratory MedicineSichuan Academy of Medical Sciences&Sichuan Provincial People’s HospitalChengdu 610072China Department of Biochemistry and Molecular Biology Center for Cellular and Molecular DiagnosisSchool of MedicineTulane UniversityNew OrleansLA 70112USA The M.O.E.Key Laboratory of Laboratory Medical Diagnostics the College of Laboratory MedicineChongqing Medical UniversityChongqing 400016China

Extracellular vesicles(EVs)are secreted by both eukaryotes and prokaryotes,and are present in all biological fluids of vertebrates,where they transfer DNA,RNA,proteins,lipids,and metabolites from donor to recipient cells in cell-to-cell communication.Some EV components can also indicate the type and biological status of their parent cells and serve as diagnostic targets for liquid biopsy.EVs can also natively carry or be modified to contain therapeutic agents(e.g.,nucleic acids,proteins,polysaccharides,and small molecules)by physical,chemical,or bioengineering strategies.Due to their excellent biocompatibility and stability,EVs are ideal nanocarriers for bioactive ingredients to induce signal transduction,immunoregulation,or other therapeutic effects,which can be targeted to specific cell types.Herein,we review EV classification,intercellular communication,isolation,and characterization strategies as they apply to EV therapeutics.This review focuses on recent advances in EV applications as therapeutic carriers from in vitro research towards in vivo animal models and early clinical applications,using representative examples in the fields of cancer chemotherapeutic drug,cancer vaccine,infectious disease vaccines,regenerative medicine and gene therapy.Finally,we discuss current challenges for EV therapeutics and their future development.

关键词： Extracellular vesicle Therapeutic agent Delivery carrier Outer membrane vesicle Cancer therapy Infectious disease vaccine Regenerative medicine Gene therapy

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Synchronous optimization of strengths, ductility and corrosion resistances of bulk nanocrystalline 304 stainless steel

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Journal of Materials Science & Technology 2020年第2期37卷 161-172页

作者： S.G.Wang M.Sun S.y.liu X.liu y.H.Xu C.B.Gong K.Long Z.D.Zhang Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang110016China

Structural materials usually suffer from several attacks during their service,such as tension,fatigue and corrosion.It is necessary to synchronously improve these properties for their lightweight and longlifetime,but corrosion resistance and ductility are generally inverse correlation with strength,it is very difficult to simultaneously optimize all three properties.However,bulk nanocrystalline 304 stainless steel(BN-304SS)produced by severe rolling technology possessed the larger yield and ultimate tensile strengths with sufficient elongation(>40%)during tensile test,the larger saturation stress and longer lifetime during low-cycle fatigue,the enhanced uniform and pitting corrosion resistances during fiveday immersion test in 6 mol/L HCl,the lowered stress corrosion cracking(SCC)susceptibility with larger yield(~2.40 GPa)and ultimate tensile(~2.66 GPa)strengths,and enough elongation(>30%)during stress corrosion in comparison with conventional polycrystalline 304 stainless steel(CP-304 SS)counterpart.The uniform and pitting corrosion resistances of fractured BN-304SS were enhanced in comprsion with those of fractured CP-304 SS during seven-day immersion test in 1 mol/L HCl.These results demonstrated the strengths,ductility and corrosion resistances of BN-304SS can be simultaneously optimized by severe rolling technology.These improved results of BN-304SS in different disciplines were understood by its valence electron configurations rather than traditional microstructural parameters.

关键词： Stainless steel Pitting corrosion Stress corrosion Tensile properties Low-cycle fatigue Severe rolling technology

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Fabrication of large-bulk ultrafine grained 6061 aluminum alloy by rolling and low-heat-input friction stir welding

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Journal of Materials Science & Technology 2018年第1期34卷 112-118页

作者： C.y.liu B.Qu P.Xue Z.y.Ma K.Luo M.Z.Ma R.P.liu Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Key Laboratory of New Processing Technology for Nonferrous Metal & Materials Ministry of Education Guilin University of Technology Guangxi Key Laboratory of Universities for Clean Metallurgy and Comprehensive Utilization of Nonferrous Metal Resources Guilin University of Technology State Key Laboratory of Metastable Materials Science and Technology Yanshan University

In this study, the ultrafine grained （UFG） 6061 Al alloys fabricated by cold rolling were friction stir welded （FSW） with different rotation rates under both air cooling and rapid cooling in water. Low-heat-input parameters of 400 rpm rotation rate in water （400-Water） could effectively inhibit the coarsening of recrystallized grains, reduce the precipitation rate, and retain more dislocations of the UFG 6061 Al parent metal. 400-Water joint showed high lowest-hardness value, narrow low-hardness zone, and high tensile strength, attributing to the effect of dislocation, grain boundary, solid-solution, and precipitation hardening. This work provides an effective strategy to fabricate large-sized bulk UFG AI alloy by cold rolling with large deformation and low-heat-input FSW.

关键词： Aluminum alloys Ultrafine grained materia Friction stir welding Mechanical properties

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A review of chatter vibration research in milling

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Chinese Journal of Aeronautics 2019年第2期32卷 215-242页

作者： Caixu yUE Haining GAO Xianli liu Steven y.LIANG Lihui WANG Harbin University of Science and Technology Georgia Institute of Technology KTH Royal Institute of Technology

Chatter is a self-excited vibration of parts in machining systems. It is widely present across a range of cutting processes, and has an impact upon both efficiency and quality in production processing. A great deal of research has been dedicated to the development of technologies that are able to predict and detect chatter. The purpose of these technologies is to facilitate the avoidance of chatter during cutting processes, which leads to better surface precision, higher productivity,and longer tool life. This paper summarizes the current state of the art in research regarding the problems of how to arrive at stable chatter prediction, chatter identification, and chatter control/-suppression, with a focus on milling processes. Particular focus is placed on the theoretical relationship between cutting chatter and process damping, tool runout, and gyroscopic effect, as well as the importance of this for chatter prediction. The paper concludes with some reflections regarding possible directions for future research in this field.

关键词： Chatter Gyroscopic effects Milling Process damping Tool runout

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Targeted Mitochondrial Delivery to Hepatocytes:A Review

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Journal of Clinical and Translational Hepatology 2022年第2期10卷 321-328页

作者： Brent D.Heineman Xiaocong liu George y.Wu Department of Medicine Division of Gastroenterology-HepatologyUniversity of Connecticut Health CenterFarmingtonCTUSA

Defects in mitochondria are responsible for various genetic and acquired diseases.Mitochondrial transplantation,a method that involves introduction of healthy donor mitochondria into cells with dysfunctional mitochondria,could offer a novel approach to treat such diseases.Some studies have demonstrated the therapeutic benefit of mitochondrial transplantation and targeted delivery in vivo and in vitro within hepatocytes and the liver.This review discusses the issues regarding isolation and delivery of mitochondria to hepatocytes and the liver,and examines the existing literature in order to elucidate the utility and practicality of mito-chondrial transplantation in the treatment of liver disease.Studies reviewed demonstrate that mitochondrial uptake could specifically target hepatocytes,address the challenge of non-specific localization of donor mitochondria,and provide evidence of changes in liver function following injection of mitochondria into mouse and rat disease models.While potential benefits and advantages of mitochondrial trans-plantation are evident,more research is needed to determine the practicality of mitochondrial transplantation for the treatment of genetic and acquired liver diseases.

关键词： Mitochondria Hepatocytes Transplantation Liver In vitro tech-niques

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Recognition Interactions of Metal-complexing Imprinted Polymer

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Chinese Chemical Letters 2005年第6期16卷 797-800页

作者： liu, y Ding, GS De Wang, J Chinese Acad Sci Dalian Inst Chem Phys Dalian 116012 Peoples R China

Molecularly imprinted polymer,exhibiting considerable enantioselectivity for L-mandelic acid,was prepared using metal coordination-chelation interaction.By evaluating the recognition characteristics in the chromatographic mode,the recognition interactions were proposed:specific and nonspecific metal coordination-chelation interaction and hydrophobic interaction were responsible for substrate binding on metal-complexing imprinted polymer;while the selective recognition only came from specific metal coordination-chelation interaction and specific hydrophobic interaction.

关键词： Molecularly imprinted polymer metal coordination-chelation interaction recognition interaction enantioseparation.

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Benzo[1,2-c;4,5-c']bis[1,2,5]thiadiazole-porphyrin-based near-infrared dyes

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SmartMat 2021年第3期2卷 398-405页

作者： yi liu Shaofei Wu Tullimilli y.Gopalakrishna Jishan Wu Department of Chemistry National University of SingaporeSingaporeSingapore Joint School of National University of Singapore and Tianjin University International Campus of Tianjin UniversityFuzhouBinhai New CityChina

Benzo[1,2-c;4,5-cʹ]bis[1,2,5]thiadiazole(BBT)has intrinsic diradical character and herein it is used to construct organic near-infrared(NIR)dyes together with the aromatic porphyrin unit.Three BBT-porphyrin hybrid dyes 1-3 with different linkage modes are synthesized by Pd-catalyzed Sonogashira crosscoupling between meso-ethynylene porphyrin units and monobromo-/dibromo-BBT,or through unexpected homocoupling between the BBT units.They all possess small open-shell diradical character and display intense NIR absorption in the range of 800-1000 nm.They also exhibit amphoteric redox behavior.BBT-based diradicaloids are thus good candidates for organic NIR dyes.

关键词： benzo[1,2-c 4,5-c']bisthiadiazole diradical character near-infrared dye porphyrin

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Kinetics of Al Evaporation from Liquid U-Al Alloys in Vacuum Induction Melting

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Journal of Materials Science & Technology 2015年第4期31卷 423-426页

作者： y.J.Duan B.Chen y.C.Ma K.liu Materials for Special Environment Division Institute of Metal ResearchChinese Academy of Sciences

A research on kinetics of Al evaporation from liquid U—Al alloys was made in a vacuum induction melting（VIM） furnace at 1673—1843 K.The evaporation rate of Al was found to be first order with respect to Al content in the melt.The overall mass transfer coefficient of Al was determined and it was found that the evaporation rate of Al increased with increasing temperatures.The apparent activation energy of Al evaporation at 1673-1843 K was 171.5 kJ mol-1.The value of mass transfer coefficient of Al in the liquid phase was estimated to be 3.77 × 10-6,7.41×10-6,and 9.40 × 10-6m s-1at 1673,1753,and 1843 K,respectively.Meanwhile,rate determining steps were discussed and it was concluded that the evaporation rate of Al is mainly controlled by liquid phase mass transfer.

关键词： Al evaporation Kinetics Liquid U-Al alloys Mass tr

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Inhalable metal–organic framework-mediated cuproptosis combined with PD-L1 checkpoint blockade for lung metastasis synergistic immunotherapy

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Acta Pharmaceutica Sinica B 2024年第5期14卷 2281-2297页

作者： yan C. Liu Y. Zhao G. yang H. Lv H. Li G. Li y. Fu y. Sun F. Feng y. Zhao Z. Department of Pharmaceutics Key Laboratory of Chemical Biology of Ministry of Education School of Pharmaceutical Sciences Cheelloo College of Medicine Shandong University Jinan 250012 China Key University Laboratory of Pharmaceutics & Drug Delivery Systems of Shandong Province School of Pharmaceutical Sciences Cheeloo College of Medicine Shandong University Jinan 250012 China

Cuproptosis shows enormous application prospects in lung metastasis treatment. However, the glycolysis, Cu+ efflux mechanisms, and insufficient lung drug accumulation severely restrict cuproptosis efficacy. Herein, an inhalable poly (2-(N-oxide-N,N-diethylamino)ethyl methacrylate) (OPDEA)-coated copper-based metal–organic framework encapsulating pyruvate dehydrogenase kinase 1 siRNA (siPDK) is constructed for mediating cuproptosis and subsequently promoting lung metastasis immunotherapy, namely OMP. After inhalation, OMP shows highly efficient lung accumulation and long-term retention, ascribing to the OPDEA-mediated pulmonary mucosa penetration. Within tumor cells, OMP is degraded to release Cu2+ under acidic condition, which will be reduced to toxic Cu+ to induce cuproptosis under glutathione (GSH) regulation. Meanwhile, siPDK released from OMP inhibits intracellular glycolysis and adenosine-5ʹ-triphosphate (ATP) production, then blocking the Cu+ efflux protein ATP7B, thereby rendering tumor cells more sensitive to OMP-mediated cuproptosis. Moreover, OMP-mediated cuproptosis triggers immunogenic cell death (ICD) to promote dendritic cells (DCs) maturation and CD8+ T cells infiltration. Notably, OMP-induced cuproptosis up-regulates membrane-associated programmed cell death-ligand 1 (PD-L1) expression and induces soluble PD-L1 secretion, and thus synergizes with anti-PD-L1 antibodies (aPD-L1) to reprogram immunosuppressive tumor microenvironment, finally yielding improved immunotherapy efficacy. Overall, OMP may serve as an efficient inhalable nanoplatform and afford preferable efficacy against lung metastasis through inducing cuproptosis and combining with aPD-L1. © 2024 The Authors

关键词： Copper-based metal-organic framework Cuproptosis Immunogenic cell death Immunotherapy Lung metastasis PD-L1 checkpoint blockade Transmucosal delivery Tumor microenvironment

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