[Objective] This study aimed to obtain recombinant alpha-bungarotoxin （a-BG-0 gene fusion protein with biological activity and investiagte its fusion expression. [Method] The plasmid pGEX-a-BGT was transformed into E...[Objective] This study aimed to obtain recombinant alpha-bungarotoxin （a-BG-0 gene fusion protein with biological activity and investiagte its fusion expression. [Method] The plasmid pGEX-a-BGT was transformed into E coil BL21 （DE3） and BL21 （DE3） plysS host bacteria to identify the optimal engineering strain. Fusion expression of the optimal engineering strain was induced, in order to optimize the induced expression conditions of the soluble fusion protein. [Result] JP-a-BGT was identified as the optimal engineering strain, which could express fusion protein after induced by IPTG. The optimal induced expression conditions of the soluble fusion protein were investigatect JP-a-BGT was incubated at 37 ℃ for 2.5 h and induced with 0.50 mmol4. IPTG for 4 h at 22 ℃, and the expression level of the soluble fusion protein reached 18.42%. [Conclusion] This study laid a solid foundation for the subsequent purification of fusion proteins and the separation and purification of a-BGT.展开更多
AIM:To investigate whether human acyl-CoA synthetase 5(ACSL5) is sensitive to the ACSL inhibitor triacsin C.METHODS:The ACSL isoforms ACSL1 and ACSL5 from rat as well as human ACSL5 were cloned and recombinantly expre...AIM:To investigate whether human acyl-CoA synthetase 5(ACSL5) is sensitive to the ACSL inhibitor triacsin C.METHODS:The ACSL isoforms ACSL1 and ACSL5 from rat as well as human ACSL5 were cloned and recombinantly expressed as 6xHis-tagged enzymes.Ni 2+-affinity purified recombinant enzymes were assayed at pH 7.5 or pH 9.5 in the presence or absence of triacsin C.In addition,ACSL5 transfected CaCo2 cells and intestinal human mucosa were monitored.ACSL5 expression in cellular systems was verified using Western blot and immunofluorescence.The ACSL assay mix included TrisHCl(pH 7.4),ATP,CoA,EDTA,DTT,MgCl 2,[9,103 H] palmitic acid,and triton X-100.The 200 μL reaction was initiated with the addition of solubilized,purified recombinant proteins or cellular lysates.Reactions were terminated after 10,30 or 60 min of incubation with Doles medium.RESULTS:Expression of soluble recombinant ACSL proteins was found after incubation with isopropyl betaD-1-thiogalactopyranoside and after ultracentrifugation these were further purified to near homogeneity with Ni 2+-affinity chromatography.Triacsin C selectively and strongly inhibited recombinant human ACSL5 protein at pH 7.5 and pH 9.5,as well as recombinant rat ACSL1(sensitive control),but not recombinant rat ACSL5(insensitive control).The IC50 for human ACSL5 was about 10 μmol/L.The inhibitory triacsin C effect was similar for different incubation times(10,30 and 60 min) and was not modified by the N-or C-terminal location of the 6xHis-tag.In order to evaluate ACSL5 sensitivity to triacsin C in a cellular environment,stable human ACSL5 CaCo2 transfectants and mechanically dissected normal human intestinal mucosa with high physiological expression of ACSL5 were analyzed.In both models,ACSL5 peak activity was found at pH 7.5 and pH 9.5,corresponding to the properties of recombinant human ACSL5 protein.In the presence of triacsin C(25 μmol/L),total ACSL activity was dramatically diminished in human ACSL5 transfectants as well as in ACSL5-rich human intestinal mucosa.CONCLUSION:The data strongly indicate that human ACSL5 is sensitive to triacsin C and does not compensate for other triacsin C-sensitive ACSL isoforms.展开更多
Objective:To express the soluble recombinant hemangiopoietin protein in E.coli BL21(DE3).Methods:Using human fetal live cDNA as a template,a partial cDNA fragment of HAPO coding N-terminal region was subcloned into pl...Objective:To express the soluble recombinant hemangiopoietin protein in E.coli BL21(DE3).Methods:Using human fetal live cDNA as a template,a partial cDNA fragment of HAPO coding N-terminal region was subcloned into plasmids pTrc99,pQE60 and pET32c to construct different recombinant prokaryotic expression systems.After selecting,the soluble rhHAPO fusion protein was expressed stably in E.coli BL21(DE3) by vector pET32c-HAPO and further isolated by nickelnitrilotriacetic acid(NTA) affinity chromatography.After cleavage with enterokinase,the rhHAPO protein was applied to Fast Flow SP sepharose column.Results:The rhHAPO protein had a purity of more than 95% and a good bioactivity based on the cell adhesion assay in ECV304 cells.Conclusion:We have established a protein engineering system to produce rhHAPO which may provide the possibility for clinical application.展开更多
Objective.To explore the expression characteristic of fibronectin gene in hypertr ophic scars and diabetic ul-cer tissues.Methods.The biopsies from normal skins,hypertrophic scars and diabetic foot ulc ers were taken....Objective.To explore the expression characteristic of fibronectin gene in hypertr ophic scars and diabetic ul-cer tissues.Methods.The biopsies from normal skins,hypertrophic scars and diabetic foot ulc ers were taken.The tech-nique of quantitative polymerase ch ain reaction(PCR)was used to evaluate the gene express ion of fibronectin in the above biopsies.Results.Fibronectin gene expression was enhanced in hypertrophic scars and decreased in diabetic foot ul-cers compared with that in normal ski ns.Quantitative comparison showed about 2-fold increase of fibronectin mR-NA level in hypertrophic scars and ab out 3-fold decrease of fibronectin mRNA level in diabetic ulcers as com-pared with that in normal skins.Conclusions.Fibronectin gene expression is influenced by the tissue environment.Di fferent expression and synthesis of fibronectin may cause d ifferent outcomes in wound healing.展开更多
Lectins play a crucial role in the innate immunity of invertebrates and vertebrates by recognizing and disposing of pathogens. We obtained the complete cDNA of a C-type lectin （EALecl） from Epinephelus akaara using ...Lectins play a crucial role in the innate immunity of invertebrates and vertebrates by recognizing and disposing of pathogens. We obtained the complete cDNA of a C-type lectin （EALecl） from Epinephelus akaara using RACE. The complete EALecl cDNA sequence was 827 bp. The 5-UTR and 3-UTR were 28 bp and 151 bp, respectively, in length. The sequence also contained a polyadenylation signal AATAAA and a poly（A） tail. The EALecl cDNA encodes polypeptides with 215 amino acids, including a signal peptide of 31 amino acids. The protein has a cysteine-rich region at the N terminal, a collagenous region characterized by G-X-Y repeats, a neck region, and a typical carbohydrate-recognition domain （CRD）, indicating that EALecl is a collectin. The key recognition positions of this CRD are EPD, isolated for the first time in fish. These are likely the interim types, between mannan-binding lectin and galactose-binding lectin. We evaluated the expression pattern of EALecl in 12 different tissues using RT-PCR. EALecl was expressed in all tissues, though at different levels. In addition, we inserted EALecl into an expression vector （pET-28a） for transformation into the BL21 engineering bacteria. Based on enzyme digestion and sequencing of the positive clone, we successfully constructed the EALecl recombinant expression vector.展开更多
Thymidylate synthase （TS, E.C.2.1.1.45） catalyzes a critical reaction in the only pathway of de novo synthesis of thymidylate （dTMP） in human cells, and is an important target of chemotherapy. To evaluate the inhi...Thymidylate synthase （TS, E.C.2.1.1.45） catalyzes a critical reaction in the only pathway of de novo synthesis of thymidylate （dTMP） in human cells, and is an important target of chemotherapy. To evaluate the inhibitory activities of novel compounds to TS, a convenient method of activity assay using 6x His-tagged recombinant human TS （rhTS） was established and 49 novel synthetic folate analogues were screened to discover potential TS inhibitors. During the process, 4 novel compounds were found to effectively inhibit TS, while the IC 50 of a positive control raltitrexed was 3.4 μM in this assay.展开更多
Increasing the self-resistance levels of Streptomyces is an effective strategy to improve the production of antibiotics.To increase the oxytetracycline(OTC) production in Streptomyces rimosus,we investigated the coope...Increasing the self-resistance levels of Streptomyces is an effective strategy to improve the production of antibiotics.To increase the oxytetracycline(OTC) production in Streptomyces rimosus,we investigated the cooperative effect of three co-overexpressing OTC resistance genes:one gene encodes a ribosomal protection protein(otrA) and the other two express efflux proteins(otrB and otrC).Results indicated that combinational overexpression of otrA,otrB,and otrC(MKABC) exerted a synergetic effect.OTC production increased by 179%in the recombinant strain compared with that of the wild-type strain M4018.The resistance level to OTC was increased by approximately two-fold relative to the parental strain,thereby indicating that applying the cooperative effect of self-resistance genes is useful to improve OTC production.Furthermore,the previously identified cluster-situated activator OtcR was overexpressed in MKABC in constructing the recombinant strain MKRABC;such strain can produce OTC of approximately7.49 g L^((-1)),which represents an increase of 19%in comparison with that of the OtcR-overexpressing strain alone.Our work showed that the cooperative overexpression of self-resistance genes is a promising strategy to enhance the antibiotics production in Streptomyces.展开更多
文摘[Objective] This study aimed to obtain recombinant alpha-bungarotoxin （a-BG-0 gene fusion protein with biological activity and investiagte its fusion expression. [Method] The plasmid pGEX-a-BGT was transformed into E coil BL21 （DE3） and BL21 （DE3） plysS host bacteria to identify the optimal engineering strain. Fusion expression of the optimal engineering strain was induced, in order to optimize the induced expression conditions of the soluble fusion protein. [Result] JP-a-BGT was identified as the optimal engineering strain, which could express fusion protein after induced by IPTG. The optimal induced expression conditions of the soluble fusion protein were investigatect JP-a-BGT was incubated at 37 ℃ for 2.5 h and induced with 0.50 mmol4. IPTG for 4 h at 22 ℃, and the expression level of the soluble fusion protein reached 18.42%. [Conclusion] This study laid a solid foundation for the subsequent purification of fusion proteins and the separation and purification of a-BGT.
基金Supported by Deutsche Forschungsgemeinschaft, No. GA785/6-1Deutsche Krebshilfe, No. 109313the Rotationsprogramm of the Medical Faculty RWTH Aachen University (to Kaemmerer E)
文摘AIM:To investigate whether human acyl-CoA synthetase 5(ACSL5) is sensitive to the ACSL inhibitor triacsin C.METHODS:The ACSL isoforms ACSL1 and ACSL5 from rat as well as human ACSL5 were cloned and recombinantly expressed as 6xHis-tagged enzymes.Ni 2+-affinity purified recombinant enzymes were assayed at pH 7.5 or pH 9.5 in the presence or absence of triacsin C.In addition,ACSL5 transfected CaCo2 cells and intestinal human mucosa were monitored.ACSL5 expression in cellular systems was verified using Western blot and immunofluorescence.The ACSL assay mix included TrisHCl(pH 7.4),ATP,CoA,EDTA,DTT,MgCl 2,[9,103 H] palmitic acid,and triton X-100.The 200 μL reaction was initiated with the addition of solubilized,purified recombinant proteins or cellular lysates.Reactions were terminated after 10,30 or 60 min of incubation with Doles medium.RESULTS:Expression of soluble recombinant ACSL proteins was found after incubation with isopropyl betaD-1-thiogalactopyranoside and after ultracentrifugation these were further purified to near homogeneity with Ni 2+-affinity chromatography.Triacsin C selectively and strongly inhibited recombinant human ACSL5 protein at pH 7.5 and pH 9.5,as well as recombinant rat ACSL1(sensitive control),but not recombinant rat ACSL5(insensitive control).The IC50 for human ACSL5 was about 10 μmol/L.The inhibitory triacsin C effect was similar for different incubation times(10,30 and 60 min) and was not modified by the N-or C-terminal location of the 6xHis-tag.In order to evaluate ACSL5 sensitivity to triacsin C in a cellular environment,stable human ACSL5 CaCo2 transfectants and mechanically dissected normal human intestinal mucosa with high physiological expression of ACSL5 were analyzed.In both models,ACSL5 peak activity was found at pH 7.5 and pH 9.5,corresponding to the properties of recombinant human ACSL5 protein.In the presence of triacsin C(25 μmol/L),total ACSL activity was dramatically diminished in human ACSL5 transfectants as well as in ACSL5-rich human intestinal mucosa.CONCLUSION:The data strongly indicate that human ACSL5 is sensitive to triacsin C and does not compensate for other triacsin C-sensitive ACSL isoforms.
基金the Natural Science Foundation of China (30300186)the Grant of 863 projects from the Ministry of Science & Technology of China (2002AA223354)
文摘Objective:To express the soluble recombinant hemangiopoietin protein in E.coli BL21(DE3).Methods:Using human fetal live cDNA as a template,a partial cDNA fragment of HAPO coding N-terminal region was subcloned into plasmids pTrc99,pQE60 and pET32c to construct different recombinant prokaryotic expression systems.After selecting,the soluble rhHAPO fusion protein was expressed stably in E.coli BL21(DE3) by vector pET32c-HAPO and further isolated by nickelnitrilotriacetic acid(NTA) affinity chromatography.After cleavage with enterokinase,the rhHAPO protein was applied to Fast Flow SP sepharose column.Results:The rhHAPO protein had a purity of more than 95% and a good bioactivity based on the cell adhesion assay in ECV304 cells.Conclusion:We have established a protein engineering system to produce rhHAPO which may provide the possibility for clinical application.
文摘Objective.To explore the expression characteristic of fibronectin gene in hypertr ophic scars and diabetic ul-cer tissues.Methods.The biopsies from normal skins,hypertrophic scars and diabetic foot ulc ers were taken.The tech-nique of quantitative polymerase ch ain reaction(PCR)was used to evaluate the gene express ion of fibronectin in the above biopsies.Results.Fibronectin gene expression was enhanced in hypertrophic scars and decreased in diabetic foot ul-cers compared with that in normal ski ns.Quantitative comparison showed about 2-fold increase of fibronectin mR-NA level in hypertrophic scars and ab out 3-fold decrease of fibronectin mRNA level in diabetic ulcers as com-pared with that in normal skins.Conclusions.Fibronectin gene expression is influenced by the tissue environment.Di fferent expression and synthesis of fibronectin may cause d ifferent outcomes in wound healing.
基金Supported by the Natural Science Foundation of Fujian Province of China (No 2060203)New Century Excellent Talents supporting funding of Fujian Province
文摘Lectins play a crucial role in the innate immunity of invertebrates and vertebrates by recognizing and disposing of pathogens. We obtained the complete cDNA of a C-type lectin （EALecl） from Epinephelus akaara using RACE. The complete EALecl cDNA sequence was 827 bp. The 5-UTR and 3-UTR were 28 bp and 151 bp, respectively, in length. The sequence also contained a polyadenylation signal AATAAA and a poly（A） tail. The EALecl cDNA encodes polypeptides with 215 amino acids, including a signal peptide of 31 amino acids. The protein has a cysteine-rich region at the N terminal, a collagenous region characterized by G-X-Y repeats, a neck region, and a typical carbohydrate-recognition domain （CRD）, indicating that EALecl is a collectin. The key recognition positions of this CRD are EPD, isolated for the first time in fish. These are likely the interim types, between mannan-binding lectin and galactose-binding lectin. We evaluated the expression pattern of EALecl in 12 different tissues using RT-PCR. EALecl was expressed in all tissues, though at different levels. In addition, we inserted EALecl into an expression vector （pET-28a） for transformation into the BL21 engineering bacteria. Based on enzyme digestion and sequencing of the positive clone, we successfully constructed the EALecl recombinant expression vector.
基金supported by National Natural Science Foundation of China(Grant No.20972011,21042009,21172014)
文摘Thymidylate synthase （TS, E.C.2.1.1.45） catalyzes a critical reaction in the only pathway of de novo synthesis of thymidylate （dTMP） in human cells, and is an important target of chemotherapy. To evaluate the inhibitory activities of novel compounds to TS, a convenient method of activity assay using 6x His-tagged recombinant human TS （rhTS） was established and 49 novel synthetic folate analogues were screened to discover potential TS inhibitors. During the process, 4 novel compounds were found to effectively inhibit TS, while the IC 50 of a positive control raltitrexed was 3.4 μM in this assay.
基金supported by funding from Shengxue Dacheng Pharmaceutical Co.,Ltd,National Natural Science Foundation of China(31400034 and 31570031)the Ministry of Science and Technology of China(2013CB734001)
文摘Increasing the self-resistance levels of Streptomyces is an effective strategy to improve the production of antibiotics.To increase the oxytetracycline(OTC) production in Streptomyces rimosus,we investigated the cooperative effect of three co-overexpressing OTC resistance genes:one gene encodes a ribosomal protection protein(otrA) and the other two express efflux proteins(otrB and otrC).Results indicated that combinational overexpression of otrA,otrB,and otrC(MKABC) exerted a synergetic effect.OTC production increased by 179%in the recombinant strain compared with that of the wild-type strain M4018.The resistance level to OTC was increased by approximately two-fold relative to the parental strain,thereby indicating that applying the cooperative effect of self-resistance genes is useful to improve OTC production.Furthermore,the previously identified cluster-situated activator OtcR was overexpressed in MKABC in constructing the recombinant strain MKRABC;such strain can produce OTC of approximately7.49 g L^((-1)),which represents an increase of 19%in comparison with that of the OtcR-overexpressing strain alone.Our work showed that the cooperative overexpression of self-resistance genes is a promising strategy to enhance the antibiotics production in Streptomyces.
