scholarly journals Constitutive Optimized Production of Streptokinase inSaccharomyces cerevisiaeUtilizing Glyceraldehyde 3-Phosphate Dehydrogenase Promoter ofPichia pastoris

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Ravi N. Vellanki ◽  
Ravichandra Potumarthi ◽  
Kiran K. Doddapaneni ◽  
Naveen Anubrolu ◽  
Lakshmi N. Mangamoori

A novel expression vector constructed from genes ofPichia pastoriswas applied for heterologous gene expression inSaccharomyces cerevisiae. Recombinant streptokinase (SK) was synthesized by cloning the region encoding mature SK under the control of glyceraldehyde 3-phosphate dehydrogenase (GAP) promoter ofPichia pastorisinSaccharomyces cerevisiae. SK was intracellularly expressed constitutively, as evidenced by lyticase-nitroanilide and caseinolytic assays. The functional activity was confirmed by plasminogen activation assay andin vitroclot lysis assay. Stability and absence of toxicity to the host with the recombinant expression vector as evidenced by southern analysis and growth profile indicate the application of this expression system for large-scale production of SK. Two-stage statistical approach, Plackett-Burman (PB) design and response surface methodology (RSM) was used for SK production medium optimization. In the first stage, carbon and organic nitrogen sources were qualitatively screened by PB design and in the second stage there was quantitative optimization of four process variables, yeast extract, dextrose, pH, and temperature, by RSM. PB design resulted in dextrose and peptone as best carbon and nitrogen sources for SK production. RSM method, proved as an efficient technique for optimizing process conditions which resulted in 110% increase in SK production, 2352 IU/mL, than for unoptimized conditions.

Author(s):  
Rafid A. Abdulkareem

The main goal of the current study was cloning and expression of the human insulin gene in Pichia pastoris expression system, using genetic engineering techniques and its treatment application. Total RNA was purified from fresh normal human pancreatic tissue. RNA of good quality was chosen to obtain a first single strand cDNA. Human preproinsulin gene was amplified from cDNA strand, by using two sets of specific primers contain EcoR1 and Notl restriction sites. The amplified preproinsulin gene fragment was double digested with EcoRI and Not 1 restriction enzymes, then inserted into pPIC9K expression vector. The new pPIC9K-hpi constructive expression vector was transformed by the heat-shock method into the E.coli DH5α competent cells. pPic9k –hpi, which was propagated in the positive transformant E. coli cells, was isolated from cells and then linearised by restriction enzyme SalI, then transformed into Pichia pastoris GS115 using electroporation method. Genomic DNA of His+ transformants cell was extracted and used as a template for PCR analysis. The results showed, that the pPic9k – hpi was successfully integrated into the P. pastoris genome, for selected His+ transformants clones on the anticipated band at 330 bp, which is corresponded to the theoretical molecular size of the human insulin gene. To follow the insulin expression in transformans, Tricine–SDS gel electrophoresis and Western blot analysis were conducted. The results showed a successful expression of recombinant protein was detected by the presence of a single major band with about (5.8 KDa) on the gel. These bands correspond well with the size of human insulin with the theoretical molecular weight (5.8 KDa).


Author(s):  
Arnis Strods ◽  
Dagnija Argule ◽  
Indulis Cielens ◽  
Ludmila Jackeviča ◽  
Regīna Renhofa

Our previous research showed that the best yield of virus-like particles (VLPs) formed by RNA bacteriophage GA coat protein was obtained by expression in yeast Pichia pastoris, while other used expression systems in Saccharomyces cerevisiae gave much lower amounts of capsids. The main reasons to attempt further studies in Saccharomyces cerevisiae were to improve the yield of GA-based VLPs using constructs with optimised nucleotide triplets in coding sequences, and to exploit the possibilities of the two-promoter Gal1/Gal10 system of expression vector pESC-URA for production of the desired mosaic VLPs and for packaging of mRNAs into VLPs in vivo


2013 ◽  
Vol 798-799 ◽  
pp. 1007-1012
Author(s):  
Wen He Zhu ◽  
Wei Zhang ◽  
Yan Li ◽  
Jun Jie Xu ◽  
Shi Jie Lv

Melittin is a novel peptide of biological activity isolated from bee venom. It has potential application value in medicine and agriculture. Here we encoded melittin gene with the EK recognition sequence in the N-terminus into expression vector pGEX-2T.The expressed fusion protein, which is about 29KDa, identified by Western Blot. To facilitate large-scale production of recombinant GST-fusion protein, we optimized different expression conditions to increase the overall production of the fusion protein. The production of the protein had increased about 10-fold when we used an auto-inducing medium. The GST fusion protein showed an equivalent activity with the natural melittin after digested by EK and can inhibited the proliferations of several human cancer lines. The expression system described in this study provides a feasible way for producing melittin in further studies.


1999 ◽  
Vol 22 (3) ◽  
pp. 273-283 ◽  
Author(s):  
C Sen Gupta ◽  
RR Dighe

Human chorionic gonadotropin (hCG), a heterodimeric glycoprotein hormone, is composed of an alpha subunit noncovalently associated with the hormone-specific beta subunit. The objective of the present study was recombinant expression of properly folded, biologically active hCG and its subunits using an expression system that could be used for structure-function studies while providing adequate quantities of the hormone for immunocontraceptive studies. We report here expression of biologically active hCG and its subunits using a yeast expression system, Pichia pastoris. The recombinant hCGalpha and hCGbeta subunits were secreted into the medium and the levels of expression achieved at shake culture level were 24 and 2.7-3 mg/l secretory medium respectively. Co-expression of both subunits in the same cell resulted in secretion of heterodimeric hCG into the medium. The pichia-expressed hCG was immunologically similar to the native hormone, capable of binding to the LH receptors and stimulating a biological response in vitro. Surprisingly, the maximal response obtained was twice that obtained with the native hCG. The level of expression of hCG achieved was 12-16 mg/l secretory medium and is expected to increase several-fold in a fermentor. Thus the Pichia expression system is capable of hyperexpressing properly folded, biologically active hCG and is suitable for structure-function studies of the hormone.


1995 ◽  
Vol 6 (1) ◽  
pp. 72-78 ◽  
Author(s):  
G.F. Herrmann ◽  
C. Krezdorn ◽  
M. Malissard ◽  
R. Kleene ◽  
H. Paschold ◽  
...  

Author(s):  
Bin Cheng ◽  
Di Wu ◽  
Ke Wu ◽  
Xiao-Ping Huang ◽  
Jian-Min Lv ◽  
...  

Abstract C-reactive protein (CRP) is a circulating marker of inflammation yet with ill-defined biological functions. This is partly due to the uncharacterized activities of endogenous CRP in mice, the major animal model used to define protein function. The hurdles for purification and characterization of mouse CRP are its low circulating levels and the lack of specific antibodies. To clear these hurdles, here we developed an efficient expression system by constructing recombinant Pichia pastoris cells for secretion of native conformation mouse CRP. The recombinant expression of mouse CRP in Escherichia coli failed to yield sufficient amount of native protein, reflecting the importance of post-translational modification of glycosylation in aiding proper folding. By contrast, sufficient amount of native mouse CRP was successfully purified from P. pastoris. Preliminary purification was performed by Nickel Chelating Sepharose Fast-Flow affinity chromatography with 6 × His tags attached to the protein. Subsequently, p-Aminophenyl Phosphoryl Choline Agarose resin affinity chromatography was used for tandem purification. The purified mouse CRP showed native pentamer and capabilities of PC binding. Moreover, the 6 × His tag provides a convenient tool for detecting the interactions of mouse CRP with ligands.


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