Background: Granulocyte colony-stimulating factor (G-CSF) expressed in engineered
Escherichia coli (E. coli) as a recombinant protein is utilized as an adjunct to chemotherapy
for improving neutropenia. Recombinant proteins overexpression may lead to the creation
of inclusion bodies whose recovery is a tedious and costly process. To overcome the problem
of inclusion bodies, secretory production might be used. To achieve a mature secretory protein
product, suitable signal peptide (SP) selection is a vital step.
Objective: In the present study, we aimed at in silico evaluation of proper SPs for secretory production
of recombinant G-CSF in E. coli.
Methods: Signal peptide website and UniProt were used to collect the SPs and G-CSF sequences.
Then, SignalP were utilized in order to predict the SPs and location of their cleavage site.
Physicochemical features and solubility were investigated by ProtParam and Protein-sol tools.
Fusion proteins sub-cellular localization was predicted by ProtCompB.
Results: LPP, ELBP, TSH, HST3, ELBH, AIDA and PET were excluded according to SignalP.
The highest aliphatic index belonged to OMPC, TORT and THIB and PPA. Also, the highest
GRAVY belonged to OMPC, ELAP, TORT, BLAT, THIB, and PSPE. Furthermore, G-CSF
fused with all SPs were predicted as soluble fusion proteins except three SPs. Finally, we found
OMPT, OMPF, PHOE, LAMB, SAT, and OMPP can translocate G-CSF into extracellular space.
Conclusion: Six SPs were suitable for translocating G-CSF into the extracellular media. Although
growing data indicate that the bioinformatics approaches can improve the precision and accuracy
of studies, further experimental investigations and recent patents explaining several inventions
associated to the clinical aspects of SPs for secretory production of recombinant GCSF
in E. coli are required for final validation.