Objective:To investigate the multienzyine complex formation of human malaria parasite Plasmodium falciparum[P.falciparum)orotate phosphoribosyltransferase(OPRT)and orotidine5'-monophosphate decarboxylase(OMPDC),th...Objective:To investigate the multienzyine complex formation of human malaria parasite Plasmodium falciparum[P.falciparum)orotate phosphoribosyltransferase(OPRT)and orotidine5'-monophosphate decarboxylase(OMPDC),the fifth and sixth enzyme of the de novo pyrimidine biosynthetic palhway.Previously,we have clearly established that the two enzymes in the malaria parasite exist physically as a heterotetrameric(OPRT)_2(OMPDG)_2 complex containing two subunits each of OPRT and OMPDC.and that the complex have catalytic kinetic advantages over the monofunetional enzyme.Methods:Both enzymes were cloned and expressed as recombinant proteins.The protein-protein interaction in the enzyme complex was identified using bifunctionul chemical cross-linker,liquid chromatography-mass spectrometric analysis and homology modeling,Results:The unique insertions of low complexity region at the a 2 and a 5 helices of the parasite OMPDC,characterized by single amino acid repeat sequence which was not found in homologous proteins from other organisms,was located on the OPRT-OMPDC interface.The structural models for the protein-prolein interaction of the helerotetrameric(OPRT)_2(OMPDC)_2multienzyme complex were proposed.Conclusions:Based on the proteomic data and structural modeling,it is surmised that the human malaria parasite low complexity region is responsible for the OPRT-OMPDC interaction.The structural complex of the parasite enzymes,thus,represents an efficient functional kinetic advantage,which in line with co-localization principles of evolutional origin,and allosteric control in protein-protein-interactions.展开更多
Microstructure and phase transformation of disodium guanosine 5′-monophosphate(5′-GMPNa_2) are extremely important for controlling the process and understanding the mechanism of crystallization. In this work, the th...Microstructure and phase transformation of disodium guanosine 5′-monophosphate(5′-GMPNa_2) are extremely important for controlling the process and understanding the mechanism of crystallization. In this work, the thermodynamic properties of polymorphous 5′-GMPNa_2 especially the solubility were studied, the solubility results show that 5′-GMPNa_2 is more soluble in ethanol–water(E–W) than in isopropanol–water(I–W). The amorphous form of 5′-GMPNa_2 is more soluble than the crystalline form at the same mole fraction and temperature. Meanwhile, the crystalline forms and morphologies of the residual solids were characterized by PXRD and SEM. The results indicate that solid forms of 5′-GMPNa_2 transformed spontaneously from amorphous to crystalline when the ethanol proportion is ≥20%. In addition, increasing the pH facilitates the dissolution of 5′-GMPNa_2 and helps to maintain the crystalline form. The associated Gibbs free energy values were calculated to verify the trend of transformation from amorphous to crystalline 5′-GMPNa_2. These results should help to guide the industrial crystallization process and to obtain the crystalline form of 5′-GMPNa_2.展开更多
Objective：To investigate the effect of Dan-gua Fang（丹瓜方） on adenosine 5’-monophosphate（AMP） activated protein kinase（AMPK） α expression in liver and subsequent improvement of glucose and lipid metabolism.M...Objective：To investigate the effect of Dan-gua Fang（丹瓜方） on adenosine 5’-monophosphate（AMP） activated protein kinase（AMPK） α expression in liver and subsequent improvement of glucose and lipid metabolism.Methods：Forty 13-week-old diabetic Goto-Kakizaki（GK） rats were randomly divided into model,Dan-gua Fang,metformin and simvastatin groups（n=10 for each）,and fed high-fat diet ad libitum.Ten Wistar rats were used as normal group and fed normal diet.After 24 weeks,liver expression of AMPK α mRNA was assessed by real-time PCR.AMPK α and phospho-AMPK α protein expression in liver was evaluated by Western blot.Liver histomorphology was carried out after hematoxylin-eosin staining,and blood glucose（BG）,glycosylated hemoglobin A1c（HbA1c）,food intake and body weight recorded.Results：Similar AMPK α mRNA levels were found in the Dan-gua Fang group and normal group,slightly higher than the values obtained for the remaining groups（P〈0.05）.AMPK α protein expression in the Dan-gua Fang group animals was similar to other diabetic rats,whereas phospho-AMPK α（Thr-172） protein levels were markedly higher than in the metformin group and simvastatin group（P〈0.05）,respectively.However,phosphor-AMPKa/AMPK α ratios were similar in all groups.Dan-gua Fang reduced fasting blood glucose with similar strength to metformin,and was superior in reducing cholesterol,triglycerides,high-density lipoprotein cholesterol as well as improving low-density lipoprotein cholesterol in comparison with simvastatin and metformin.Dan-gua Fang decreases plasma alanine aminotransferase（ALT） significantly.Conclusion：Dan-gua Fang,while treating phlegm-stasis,could decrease BG and lipid in type 2 diabetic GK rats fed with high-fat diet,and effectively protect liver histomorphology and function.This may be partly explained by increased AMPK expression in liver.Therefore,Dan-gua Fang might be an ideal drug for comprehensive Intervention for glucose and lipid metabolism disorders in type 2 diabetes mellitus.展开更多
基金supported in part by Faculty of Graduate School(to W.L)Faculty of Medicine(contract no. RAH/54(1) to J.K.),Chulalongkorn University
文摘Objective:To investigate the multienzyine complex formation of human malaria parasite Plasmodium falciparum[P.falciparum)orotate phosphoribosyltransferase(OPRT)and orotidine5'-monophosphate decarboxylase(OMPDC),the fifth and sixth enzyme of the de novo pyrimidine biosynthetic palhway.Previously,we have clearly established that the two enzymes in the malaria parasite exist physically as a heterotetrameric(OPRT)_2(OMPDG)_2 complex containing two subunits each of OPRT and OMPDC.and that the complex have catalytic kinetic advantages over the monofunetional enzyme.Methods:Both enzymes were cloned and expressed as recombinant proteins.The protein-protein interaction in the enzyme complex was identified using bifunctionul chemical cross-linker,liquid chromatography-mass spectrometric analysis and homology modeling,Results:The unique insertions of low complexity region at the a 2 and a 5 helices of the parasite OMPDC,characterized by single amino acid repeat sequence which was not found in homologous proteins from other organisms,was located on the OPRT-OMPDC interface.The structural models for the protein-prolein interaction of the helerotetrameric(OPRT)_2(OMPDC)_2multienzyme complex were proposed.Conclusions:Based on the proteomic data and structural modeling,it is surmised that the human malaria parasite low complexity region is responsible for the OPRT-OMPDC interaction.The structural complex of the parasite enzymes,thus,represents an efficient functional kinetic advantage,which in line with co-localization principles of evolutional origin,and allosteric control in protein-protein-interactions.
基金Supported by the Program for Changjiang Scholars and Innovative Research Team in University(IRT_14R28)the National Basic Research Program of China(2013CB733602)+4 种基金the Major Research Plan of the National Natural Science Foundation of China(21390204)the National Natural Science Foundation of China(21636003,21506090)Open Fund by Jiangsu Key Lab of Biomass-based Green Fuels and Chemicals(JSBGFC14005)Jiangsu National Synergetic Innovation Center for Advanced Materials(SICAM)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘Microstructure and phase transformation of disodium guanosine 5′-monophosphate(5′-GMPNa_2) are extremely important for controlling the process and understanding the mechanism of crystallization. In this work, the thermodynamic properties of polymorphous 5′-GMPNa_2 especially the solubility were studied, the solubility results show that 5′-GMPNa_2 is more soluble in ethanol–water(E–W) than in isopropanol–water(I–W). The amorphous form of 5′-GMPNa_2 is more soluble than the crystalline form at the same mole fraction and temperature. Meanwhile, the crystalline forms and morphologies of the residual solids were characterized by PXRD and SEM. The results indicate that solid forms of 5′-GMPNa_2 transformed spontaneously from amorphous to crystalline when the ethanol proportion is ≥20%. In addition, increasing the pH facilitates the dissolution of 5′-GMPNa_2 and helps to maintain the crystalline form. The associated Gibbs free energy values were calculated to verify the trend of transformation from amorphous to crystalline 5′-GMPNa_2. These results should help to guide the industrial crystallization process and to obtain the crystalline form of 5′-GMPNa_2.
基金Supported by the National Natural Science Foundation of China(No.81173179)the Natural Science Foundation of Fujian Province(No.2011J01198)+5 种基金the Fujian Medical Innovation Project(No.2009-CX-19)the Research Foundation of Fujian Health Department(No.Zlcnfm02)the Fujian Provincial Department of Education Category A Projects(No.JA09131)the Fujian Health Department of Traditional Chinese Medicine Research(No.WZY0920)the CHEN Ke-ji Integrative Medicine Development Fund(No.CKJ2008047,CKJ2009004)the Integrative Medicine of Fujian Key Laboratory of Age-related Diseases Funded Projects(No.2008J1004-10)
文摘Objective：To investigate the effect of Dan-gua Fang（丹瓜方） on adenosine 5’-monophosphate（AMP） activated protein kinase（AMPK） α expression in liver and subsequent improvement of glucose and lipid metabolism.Methods：Forty 13-week-old diabetic Goto-Kakizaki（GK） rats were randomly divided into model,Dan-gua Fang,metformin and simvastatin groups（n=10 for each）,and fed high-fat diet ad libitum.Ten Wistar rats were used as normal group and fed normal diet.After 24 weeks,liver expression of AMPK α mRNA was assessed by real-time PCR.AMPK α and phospho-AMPK α protein expression in liver was evaluated by Western blot.Liver histomorphology was carried out after hematoxylin-eosin staining,and blood glucose（BG）,glycosylated hemoglobin A1c（HbA1c）,food intake and body weight recorded.Results：Similar AMPK α mRNA levels were found in the Dan-gua Fang group and normal group,slightly higher than the values obtained for the remaining groups（P〈0.05）.AMPK α protein expression in the Dan-gua Fang group animals was similar to other diabetic rats,whereas phospho-AMPK α（Thr-172） protein levels were markedly higher than in the metformin group and simvastatin group（P〈0.05）,respectively.However,phosphor-AMPKa/AMPK α ratios were similar in all groups.Dan-gua Fang reduced fasting blood glucose with similar strength to metformin,and was superior in reducing cholesterol,triglycerides,high-density lipoprotein cholesterol as well as improving low-density lipoprotein cholesterol in comparison with simvastatin and metformin.Dan-gua Fang decreases plasma alanine aminotransferase（ALT） significantly.Conclusion：Dan-gua Fang,while treating phlegm-stasis,could decrease BG and lipid in type 2 diabetic GK rats fed with high-fat diet,and effectively protect liver histomorphology and function.This may be partly explained by increased AMPK expression in liver.Therefore,Dan-gua Fang might be an ideal drug for comprehensive Intervention for glucose and lipid metabolism disorders in type 2 diabetes mellitus.
