جستجوی مقالات مرتبط با کلیدواژه « Signal peptide » در نشریات گروه « زیست شناسی »

Recombinant AgB8/1 as the most evaluated antigen for serological diagnosis of Cystic Echinococcosis (CE) can provide early and accurate diagnosis for proper management and treatment of the disease. Thus, the secretory production of this recombinant protein is the main goal and the application of signal peptides at the N terminus of the desired protein can help to achieve this goal. The present study applied few bioinformatics tools to evaluate several signal peptides to offer the best candidate for extracellular production of AgB8/1 of Echinococcus granulosus in Escherichia coli. The sequences related to signal peptides were obtained from “Signal Peptide Website” and were checked by “UniProt”. In addition, UniProt was employed to retrieve the sequence of AgB8/1. Then, the probable signal peptide sequences and their cleavage site locations were determined by SignalP 4.1 followed by evaluation of their physicochemical features, using ProtParam. The solubility of the target recombinant proteins was accessed by SOLpro. Finally, PRED-TAT and ProtCompB were implemented to predict protein secretion pathways and final destinations. Among the 39 candidate signal peptides, ENTC2_STAAU and ENTC1_STAAU are the best ones which are stable and soluble in connection with AgB8/1 and can secrete target protein through Sec pathway. The signal peptides recommended in this investigation are valuable for rational designing of secretory stable and soluble AgB8/1. Such information is useful for future experimental production of the mentioned antigen.

An elevated cholesterol level might lead to cardiovascular disease (CVD). Statins block the cholesterol synthesis pathway in the liver. Atorvastatin is the most widespread statin worldwide and, its chemical synthesis requires toxic catalysts, resulting in environmental pollution. Hence, enzymatic synthesis of atorvastatin is desirable. This process could be done by Lactobacillus kefir alcohol dehydrogenase (LKADH). Therefore, recombinant enzyme secretion by Escherichia coli using signal peptides (SPs) might result in easy production and purification. To achieve this objective, we used some online bioinformatics web servers to evaluate the suitable SPs for translocation of LKADH into extracellular spaces. “Signal Peptide Website” and “UniProt” were utilized to retrieve the SPs and LKADH sequences. “SignalP 4.1” was used to determine SPs and their cleavage site location and the results were rechecked by “Philius”. Physicochemical features of SPs were evaluated by “ProtParam”, then solubility of their fusion with LKADH was assessed by “Protein-sol”. Finally, secretion pathway and sub-cellular localization of the selected stable and soluble LKADH fusions were predicted by “PRED-TAT” and “ProtCompB”. Amongst the 41 evaluated SPs, only LPTA_ECOLI, SUBF_BACSU, CHIS_BACSU, SACB_BACAM, CDGT_BACST and AMY_BACLI could translocate LKADH out of cytoplasm. The six selected SPs in the result section were suitable to design a soluble secretory LKADH that accelerate its scale-up production and might be useful in future experimental researches.

Keratinocyte Growth Factor (KGF) is a paracrine-acting and epithelium-specific growth factor produced by cells of mesenchymal origin. Based on preclinical data, recombinant KGF plays a critical role in protecting and repairing of damaged epithelial tissues. Despite great efforts to express recombinant human KG (rhKGF) in different organisms, attempts for finding appropriate protein expression system with the ability of producing a properly folded and processed KGF needs further investigation. Pichia pastoris has been used successfully and extensively for production of industrial enzymes and pharmaceutical proteins. Herein, we investigated the affect of pro-region-α-factor early deletion on production and secretion of rhKGF in Pichia pastoris. Initially, expression of human KGF induced in MCF-7 cell line treated with 1, 25-Dihydroxy vitamin D3. The coding sequence of full length rhKGF194 was then cloned into the yeast integrative expression vector, downstream of α-factor and was integrated into P. pastoris genome. KGF protein was expressed in P. pastoris x33 cells, usingα-factor signal peptide for translocation of KGF to ER. An internal human signal peptide was also arranged after α-factorfor early removal of the pro-region in ER. RT-PCR results demonstrated that KGF mRNA was expressed successfully after induction by methanol. Recombinant KGF protein expression was detected by Western blotting in cell lysats, but not in conditioned media. A molecular weight of 17 kD for rhKGF194 indicates that the α-factor and internal human signal peptideshad been removed in x33 cells. The results indicate that in the absence of pro-region-α-factor, the recombinant KGF protein was not efficiently processed and transported within the biosynthesis-secretory pathway. As KGF protein is an unstable growth factor and tend to aggregate because of some native properties, It seems that presence of a chaperon molecule fusion with KGF is necessary for efficient secretion of the recombinant protein.