N-glycan modification in Aspergillus species.
Kainz E., Gallmetzer A., Hatzl C., Nett J.H., Li H., Schinko T., Pachlinger R., Berger H., Reyes-Dominguez Y., Bernreiter A., Gerngross T., Wildt S., Strauss J.
The production by filamentous fungi of therapeutic glycoproteins intended for use in mammals is held back by the inherent difference in protein N-glycosylation and by the inability of the fungal cell to modify proteins with mammalian glycosylation structures. Here, we report protein N-glycan engineering in two Aspergillus species. We functionally expressed in the fungal hosts heterologous chimeric fusion proteins containing different localization peptides and catalytic domains. This strategy allowed the isolation of a strain with a functional alpha-1,2-mannosidase producing increased amounts of N-glycans of the Man5GlcNAc2 type. This strain was further engineered by the introduction of a functional GlcNAc transferase I construct yielding GlcNAcMan5GlcNac2 N-glycans. Additionally, we deleted algC genes coding for an enzyme involved in an early step of the fungal glycosylation pathway yielding Man3GlcNAc2 N-glycans. This modification of fungal glycosylation is a step toward the ability to produce humanized complex N-glycans on therapeutic proteins in filamentous fungi.
Appl. Environ. Microbiol. 74:1076-1086(2008) [ PubMed | SRS | CiteXplore ]
