Genetic engineering of Pichia pastoris to humanize N-glycosylation of proteins

The yeast Pichia pastoris is used extensively as the host cell for large-scale production of secreted recombinant proteins. Many proteins of pharmaceutical importance are N-glycosylated, and therefore require an expression host that yields N-linked oligosaccharides that are structurally and functionally identical to the human counterpart. The recent report by Choi et al. describes the use of combinatorial genetic libraries to alter the N-glycosylation pathway in P. pastoris to yield N-linked oligosaccharides with hybrid structures that are the same as the intermediates of mammalian-protein N-glycosylation. In view of recent progress in this area, the production of complex human glycans in yeasts is anticipated.