Alternative secretory signal sequences for recombinant protein production in Pichia pastoris

Extracellular protein production is primarily preferred to facilitate the downstream processes in recombinant protein production. Secretion of recombinant proteins is mediated by the processing of signal peptides in their N -terminal portion by the secretory mechanism of host expression systems. These molecular elements involved in secretion are functionally interchangeable between different species and secretion sequence screening is one of the widely used approaches to improve extracellular protein production. In this study, alpha-mating and protein internal repeats (PIR) secretion sequences isolated from different yeasts (Kluyveromyces lactis, Kluyveromyces marxianus and Hansenula polymorpha) were tested in Pichia pastoris for the production of two different proteins (alpha-amylase and xylanase) and compared with the well-known secretory signals, S. cerevisiae alpha-mating factor (Sc-MF) and P. pastoris protein internal repeats PIR (PpPIR). The results obtained showed the potential of signal sequences tested. Among the tested peptides, the highest yields were achieved with H. polymorpha protein in-ternal repeats (HpPIR) and K. lactis alpha-mating factor (Kl-MF) for xylanase and K. marxianus protein internal re-peats (KmPIR) and K. lactis alpha-mating factor (Kl-MF) for amylase. In further studies, these sequences can be evaluated as alternatives in the production of different proteins in P. pastoris and in the production of recom-binant proteins in different expression systems.

Automated summary

Extracellular protein production is crucial for downstream processes in recombinant protein production. Signal peptide processing plays a key role in protein secretion, and different yeast-derived secretion sequences were tested in Pichia pastoris to improve protein production. Among the tested sequences, H. polymorpha protein internal repeats (HpPIR) and K. lactis alpha-mating factor (Kl-MF) showed the highest yields for xylanase and amylase, respectively. These sequences can be considered as alternatives for protein production in various expression systems.