Background: Secretory production of heterologous proteins in bacterial hosts has been a
topic of interest due to its various advantages. However, it is difficult to achieve because of process
complexity and the need for selection of an appropriate signal peptide for each protein and host. IL-
11, marketed as Neumega®, is a multifunctional cytokine approved for platelet recovery in chemotherapy-
Objective: The in silico evaluation of 30 signal peptides for finding the best theoretical candidates
for the secretory production of recombinant IL-11 in Escherichia coli.
Methods: The prediction of signal peptide presence and location of cleavage sites were done by SignalP
4.1. Five signal peptides (ompT, npr, TorA, caf1M, and phoA) were excluded from further
evaluations due to cleavage issues. Different physicochemical properties of signal peptides, which
may affect protein secretion, were studied by ProtParam and PROSO II servers.
Results/Conclusion: Computational analysis of the influencing factors identified TorT, sfmC, and
ompC, respectively, as the best theoretical candidates for the secretory production of IL-11 in E. coli.
However, in the experimental investigation, other influencing factors and a system biology approach
should be considered.