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| 1 | Serial deletion reveals structural basis and stability for the core enzyme activity of human glutaminase 1 isoforms:relevance to excitotoxic neurodegeneration显示文摘Background:Glutaminase 1 is a phosphate-activated metabolic enzyme that catalyzes the first step of glutaminolysis,which converts glutamine into glutamate.Glutamate is the major neurotransmitter of excitatory synapses,executing important physiological functions in the central nervous system.There are two isoforms of glutaminase 1,KGA and GAC,both of which are generated through alternative splicing from the same gene.KGA and GAC both transcribe 1–14 exons in the N-terminal,but each has its unique C-terminal in the coding sequence.We have previously identified that KGA and GAC are differentially regulated during inflammatory stimulation and HIV infection.Furthermore,glutaminase 1 has been linked to brain diseases such as amyotrophic lateral sclerosis,Alzheimer’s disease,and hepatic encephalopathy.Core enzyme structure of KGA and GAC has been published recently.However,how other coding sequences affect their functional enzyme activity remains unclear.Methods:We cloned and performed serial deletions of human full-length KGA and GAC from the N-terminal and the C-terminal at an interval of approximately 100 amino acids(AAs).Prokaryotic expressions of the mutant glutaminase 1 protein and a glutaminase enzyme activity assay were used to determine if KGA and GAC have similar efficiency and efficacy to convert glutamine into glutamate.Results:When 110 AAs or 218 AAs were deleted from the N-terminal or when the unique portions of KGA and GAC that are beyond the 550 AA were deleted from the C-terminal,KGA and GAC retained enzyme activity comparable to the full length proteins.In contrast,deletion of 310 AAs or more from N-terminal or deletion of 450 AAs or more from C-terminal resulted in complete loss of enzyme activity for KGA/GAC.Consistently,when both Nand C-terminal of the KGA and GAC were removed,creating a truncated protein that expressed the central 219 AA-550 AA,the protein retained enzyme activity.Furthermore,expression of the core 219 AA-550 AA coding sequence in cells increased extracellular glutamate concentrations to levels comparable to those of full-length KGA and GAC expressions,suggesting that the core enzyme activity of the protein lies within the central 219 AA-550 AA.Full-length KGA and GAC retained enzyme activities when kept at 4°C.In contrast,219 AA-550 AA truncated protein lost glutaminase activities more readily compared with full-length KGA and GAC,suggesting that the Nterminal and C-terminal coding regions are required for the stability KGA and GAC.Conclusions:Glutaminase isoforms KGA and GAC have similar efficacy to catalyze the conversion of glutamine to glutamate.The core enzyme activity of glutaminase 1 protein is within the central 219 AA-550 AA.The N-terminal and C-terminal coding regions of KGA and GAC help maintain the long-term activities of the enzymes. | Yuju Li Justin Peer Runze Zhao Yinghua Xu Beiqing Wu Yi Wang Changhai Tian Yunlong Huang Jialin Zheng | 2017 | Translational Neurodegeneration2017，6，1： | 1 |
| 2 | Studies of syntheses and adsorption properties of chelating resin from thiourea and formaldehyde 显示文摘 | Ni Caihua Yi Changhai Feng Zhiyun | 2001 | Journal of Applied Polymer Science2001，82，13： | 1 |
| 3 | On the isomerization and dissociation of nitramide encapsulated inside an armchair(5,5) single-walled carbon nanotube显示文摘 | Luoxin Wang Changhai Yi Hantao Zou | | 0，，： | 1 |
| 4 | Adsorption of insensitive explosive TATB on single-walled carbon nanotubes显示文摘 | Luoxin Wang Changhai Yi Hantao Zou Houlei Gan Jie Xu Weilin Xu | | 0，，： | 1 |
| 5 | MoSi2-ZrO2 composites-fabrication,microstructures and properties显示文摘 | Danqing Yi Changhai Li | 1999 | Materials Science and Engineering1999，261，： | 1 |
| 6 | Recent progress of waterless technologies for Jeans washing in denim industry显示文摘This review focuses on the current situation of sustainable development of denim industry and analyzes the water consumption in the production process of denim.In the washing process of jeans,the dry treatment or near-anhydrous treatment is becoming a sustainable trend to replace the traditional wet treatment.From the perspective of environmental protection,this review summarizes the recent research frontiers of water-saving technologies such as recycling and utilization of printing and dyeing wastewater,foam finishing technology,ozone washing technology and laser washing technology in denim industry.With the upgrading of textile industry and the implementation of national environmental protection laws and regulations,technologies such as foam finishing,ozone washing and laser engraving have been well-developed in the field of denim garment washing processing.In the future,the denim industry will be revolutionized by the water-free manufacturing. | Xuejiao Fang Sheng Li Bihan Bie Changhai Yi | 2020 | 服饰导刊2020，9，3： | 0 |
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