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Volume 7 Pharmaceutical Regulatory Affairs: Open Access
ISSN: 2167-7689 Pharma Europe 2018
May 07-09, 2018
May 07-09, 2018 | Frankfurt, Germany
15th Annual European Pharma Congress
In silico analyses of several signal peptides for the excretory production of phenylalanine ammonia-
lyase in Escherichia coli
Hajar Owji and Shiva Hemmati
Shiraz University of Medical Sciences, Iran
Statement of the Problem: Day by day, the demand for biotherapeutics and recombinant proteins is increasing. Herein,
cytoplasmic expression in prokaryotic and eukaryotic hosts has been widely accepted. However, there are several obstacles
in the large-scale production of recombinant proteins. Recombinant proteins might form inclusion bodies or be degraded by
proteases. Endogenous proteins might also interfere with the folding of a recombinant secretory protein. These factors, as well
as the complicated downstream purification process, will result in loss of protein yield. Moreover, the yield of recombinant
protein is not only related to expression levels, but also to translocation efficiency. Thus, the translocation efficiency could
be increased by using signal peptides. Phenylalanine ammonialyase (PAL), involved in the first step of the phenylpropanoid
pathway, catalyzes the deamination of phenylalanine to cinnamate and ammonia. PALs are ubiquitous in plants and also
commonly found in fungi; however, animal lacks it. They are of special interest in several medical and industrial applications,
including preparation of low phenylalanine diet, treatment of phenylketonuria and certain neoplastic tumors. Although
several methods have been applied in the production of PAL, the final titers of PAL are still low, thereby impeding considerable
industrialization of this enzyme.
Objective: This study aims to evaluate a vast number of signal peptides, previously deposited in databases (1168 signal
peptides), in order to select the most appropriate ones for secretory production of PAL.
Methodology & Theoretical Orientation: Herein, the SignalP tool was applied to determine the secretion efficiency as well
as cleavage sites. Moreover, various physiochemical properties of signal peptides linked to the protein as well as secretory
pathways were identified. Effects of signal peptide addition on antigenicity, allergenicity, and mRNA secondary structure of
PAL were evaluated.
Findings: The appropriate candidates for high yield and efficient production of phenylalanine ammonia-lyse in E. coli were
identified.
Recent Publications
1. Tsirigotaki A, De Geyter J, Šoštaric N, Economou A and Karamanou S (2017) Protein export through the bacterial sec
pathway. Nature Reviews Microbiology 15(1):21–36.
2. Kong J-Q (2015) Phenylalanine ammonia-lyase, a key component used for phenylpropanoids production by metabolic
engineering. RSC Advances 5(77):62587–603.
3. Cui J D, Qiu J Q, Fan X W, Jia S R and Tan Z L (2014) Biotechnological production and applications of microbial
phenylalanine ammonia-lyase: a recent review. Critical Reviews in Biotechnology 34(3):258–68.
4. Ivankov D N, Payne S H, Galperin M Y, Bonissone S, Pevzner P A, et al. (2013) How many signal peptides are there in
bacteria? Environmental Microbiology 15(4):983–90.
5. Low K O, Mahadi N M and Illias R M (2013) Optimisation of signal peptide for recombinant protein secretion in
bacterial hosts. Applied Microbiology and Biotechnology 97(9):3811–26.
Biography
Hajar Owji completed her PharmD from Shiraz University of Medical Sciences. She is now working as a Research Pharmacist affiliated to the Department of
Pharmaceutical Biotechnology. Her research interests are focused on Bioinformatics, Molecular Biology, and Biomolecular Pharmaceutical Sciences.
Hajar Owji et al., Pharmaceut Reg Affairs 2018, Volume 7
DOI: 10.4172/2167-7689-C1-031