Humanization of Yeast to Produce Complex Terminally Sialylated Glycoproteins

TLDR

Yeast is a widely used recombinant protein expression system. The study engineered Pichia pastoris to secrete human glycoproteins with fully complex terminally sialylated N‑glycans. The authors knocked out four genes to eliminate yeast‑specific glycosylation and introduced 14 heterologous genes to replicate the sequential steps of human glycosylation. The engineered cell lines produce complex glycoproteins with >90% terminal sialylation and successfully produced functional recombinant erythropoietin.

Abstract

Yeast is a widely used recombinant protein expression system. We expanded its utility by engineering the yeast Pichia pastoris to secrete human glycoproteins with fully complex terminally sialylated N-glycans. After the knockout of four genes to eliminate yeast-specific glycosylation, we introduced 14 heterologous genes, allowing us to replicate the sequential steps of human glycosylation. The reported cell lines produce complex glycoproteins with greater than 90% terminal sialylation. Finally, to demonstrate the utility of these yeast strains, functional recombinant erythropoietin was produced.