The design of any antagonist or inhibitor for any enzyme requires the knowledge of structure- function relationship of the protein and the optimum conformational states for maximum and minimum activities. Furthermore,...The design of any antagonist or inhibitor for any enzyme requires the knowledge of structure- function relationship of the protein and the optimum conformational states for maximum and minimum activities. Furthermore, designing of the inhibitors or drugs against an enzyme becomes easier if there is information available about various well characterized intermediate conformation of the molecule. In vivo folding pathway of any recombinant protein is an important parameter for understanding its ability to fold by itself inside the cell, which always dictates the downstream processing for the purification. In the present manuscript we have discussed about the in vivo and in vitro folding, and structure-function relationship of Dihydrofolate reductase enzyme. This is an important enzyme involved in the cell growth and hence inhibition or inactivation of the enzyme may reduce the cell growth. It was observed that the equilibrium unfolding transition of DHFR proceeds through the formation of intermediates having higher exposed surface hydrophobicity, unchanged enzymatic activity and minimum changes in the secondary structural elements. Because of enhanced surface hydrophobicity, and unchanged enzymatic activity, these intermediates could be a nice target for designing drugs against DHFR.展开更多
Objective: To prepare secretary recombinant human neutrophil peptidel (HNP1)and test its antimicrobial activity. Methods: The eukaryotic expression vector pcDNA3. 1/V5-His-TOPO-HNP1 was cotransfected with plasmid pDCH...Objective: To prepare secretary recombinant human neutrophil peptidel (HNP1)and test its antimicrobial activity. Methods: The eukaryotic expression vector pcDNA3. 1/V5-His-TOPO-HNP1 was cotransfected with plasmid pDCH1P11 carrying dhfr gene into dhfr- negative CHO (CHO-dhfr- ) cells and recombinant protein was verified by ELISA; G418 selective medium was used to screen the stably expressing cell clones followed by serial passages in 5×10-8 mol/L and 5×10 mol/L methotrexate (MTX) for gene amplification. Finally 4 cell clones with high expression level were obtained and confirmed by ELISA, RT-PCR and IFA. The bacteriastatic activity of concentrated supernatants was tested in vitro as well. Results: The expression level of recombinant HNPl ranged from 18.85 mg/L·48 h to 47.46 mg/L·48 h per 106 cells that was almost 200-fold increase than that in G418 selective medium. 303 bp segments were amplified from 4 stably tranfec tant clones which matched the length of HNPl cDNA by RT-PCR. Strong fluorescence was visible in cell plasma in the sta blly transfectant cells by IFA. K-B disc agar diffusion test showed obvious bacteriastatic diffusion on MH plate of E. coli. Conclusion: HNP1cDNA can be strongly expressed in CHO-dhfr- cells, which supernatants exhibited high inhibitive effect against bacteria.展开更多
文摘The design of any antagonist or inhibitor for any enzyme requires the knowledge of structure- function relationship of the protein and the optimum conformational states for maximum and minimum activities. Furthermore, designing of the inhibitors or drugs against an enzyme becomes easier if there is information available about various well characterized intermediate conformation of the molecule. In vivo folding pathway of any recombinant protein is an important parameter for understanding its ability to fold by itself inside the cell, which always dictates the downstream processing for the purification. In the present manuscript we have discussed about the in vivo and in vitro folding, and structure-function relationship of Dihydrofolate reductase enzyme. This is an important enzyme involved in the cell growth and hence inhibition or inactivation of the enzyme may reduce the cell growth. It was observed that the equilibrium unfolding transition of DHFR proceeds through the formation of intermediates having higher exposed surface hydrophobicity, unchanged enzymatic activity and minimum changes in the secondary structural elements. Because of enhanced surface hydrophobicity, and unchanged enzymatic activity, these intermediates could be a nice target for designing drugs against DHFR.
文摘Objective: To prepare secretary recombinant human neutrophil peptidel (HNP1)and test its antimicrobial activity. Methods: The eukaryotic expression vector pcDNA3. 1/V5-His-TOPO-HNP1 was cotransfected with plasmid pDCH1P11 carrying dhfr gene into dhfr- negative CHO (CHO-dhfr- ) cells and recombinant protein was verified by ELISA; G418 selective medium was used to screen the stably expressing cell clones followed by serial passages in 5×10-8 mol/L and 5×10 mol/L methotrexate (MTX) for gene amplification. Finally 4 cell clones with high expression level were obtained and confirmed by ELISA, RT-PCR and IFA. The bacteriastatic activity of concentrated supernatants was tested in vitro as well. Results: The expression level of recombinant HNPl ranged from 18.85 mg/L·48 h to 47.46 mg/L·48 h per 106 cells that was almost 200-fold increase than that in G418 selective medium. 303 bp segments were amplified from 4 stably tranfec tant clones which matched the length of HNPl cDNA by RT-PCR. Strong fluorescence was visible in cell plasma in the sta blly transfectant cells by IFA. K-B disc agar diffusion test showed obvious bacteriastatic diffusion on MH plate of E. coli. Conclusion: HNP1cDNA can be strongly expressed in CHO-dhfr- cells, which supernatants exhibited high inhibitive effect against bacteria.
